Magnetoelastic torque sensor with extended interference field compensation

Abstract

The invention relates to a magnetoelastic torque sensor (10) having an evaluation unit (6) and at least three magnetic field sensors. The evaluation unit (6) is configured to detect at least one measurement signal of a first magnetic field sensor (1), at least one measurement signal of a second magnetic field sensor (2) and at least one third measurement signal of a third magnetic field sensor (3) of the magnetoelastic torque sensor (10) and to determine a torque applied to the shaft (5) by means of the at least one measurement signal of the first magnetic field sensor, the at least one measurement signal of the second magnetic field sensor, the at least one measurement signal of the fourth magnetic field sensor and the ratio of the distance (23) in the axial direction (111) between the second magnetic field sensor (2) and the third magnetic field sensor (3) to the distance (12) in the axial direction (111) between the first magnetic field sensor (1) and the second magnetic field sensor (2). The invention also relates to a method for determining a torque using such a magnetoelastic torque sensor (10).

Description

Background Technology

[0001] This invention relates to a magnetoelastic torque sensor and a vehicle, particularly a vehicle capable of being electrically and / or manually driven, said vehicle having a magnetoelastic torque sensor. The invention also relates to a method for determining torque when using a magnetoelastic torque sensor.

[0002] For several years, magnetostrictive torque sensors with partially magnetized shafts have been known. When a shaft is subjected to a torque load, a magnetic field is generated in a region outside the shaft. This magnetic field is proportional to the torque applied to the shaft at each location and can be measured by a magnetic field sensor of the torque sensor. Therefore, measuring the magnetic field enables the determination of the torque. However, ideal torque measurement is only possible in the absence of an additional magnetic field not generated by the torque. In this regard, the prior art recognizes magnetostrictive torque sensors that have shafts with two magnetized regions for compensating for uniform magnetic interference fields or three magnetized regions for compensating for linear magnetic interference fields. Summary of the Invention

[0003] The magnetostrictive torque sensor according to the invention has the advantage of enabling space-saving flux measurement or torque measurement that compensates for interference fields. This is achieved by considering distance, and in particular the distance ratio of the magnetic field sensors, in the flux measurement or torque measurement in a magnetostrictive torque sensor having at least three magnetic field sensors. By considering the distances of the magnetic field sensors relative to each other and the corresponding weighting or scaling of the measurement signals of the magnetic field sensors, the measurement signals can be combined to eliminate uniform interference fields and linear interference field gradients when calculating torque. For this purpose, the magnetostrictive torque sensor includes a shaft having at least one magnetized region, at least three magnetic field sensors, and an analysis and processing unit, wherein the shaft has an axial direction and a radial direction, and the magnetic field sensors each have at least one measurement axis and are configured to detect the component of the magnetic flux density of the magnetic field in the direction of the at least one measurement axis. The at least three magnetic field sensors include a first magnetic field sensor, a second magnetic field sensor, and a third magnetic field sensor. Here, the second magnetic field sensor is arranged between the first and third magnetic field sensors in the axial direction. At least one of the at least three magnetic field sensors is arranged relative to the at least one magnetized region such that the magnetic field sensor is configured to detect the component of the magnetic flux density of the magnetic field in the direction of the corresponding at least one measurement axis, the magnetic field being generated by the at least one magnetized region when the shaft is subjected to torque stress. The analysis and processing unit is configured to: detect at least one measurement signal from the first magnetic field sensor, at least one measurement signal from the second magnetic field sensor, and at least one measurement signal from the third magnetic field sensor, and determine the torque applied to the shaft based on the at least one measurement signal from the first magnetic field sensor, the at least one measurement signal from the second magnetic field sensor, at least one third measurement signal, and the ratio of the distance between the second and third magnetic field sensors in the axial direction to the distance between the first and second magnetic field sensors in the axial direction. With the proposed magnetoelastic torque sensor, especially by considering the described distance ratio when determining the torque, the measurement signals of the at least three magnetic field sensors can be verified such that uniform interference fields and linear interference field gradients in the axial direction can be compensated, in particular. Thus, it is possible to calculate a torque largely cleared of interference fields, which has neither a uniform interference field component nor a linear interference field gradient in the axial direction. Furthermore, an advantage of this invention is that no approximation is required when calculating torque in order to eliminate / compensate for gradients in uniform and linear interference fields. Since no approximation is needed, accurate torque determination is possible.A key advantage of this invention is that interference field cancellation / compensation can be achieved using a magnetostrictive torque sensor with an axis having only one or two magnetized regions. Since a magnetized region must have a minimum width to be magnetized stably and reproducibly, and the transition from one magnetized region to another must never be abrupt, omitting one or two additional magnetized regions results in a significant reduction in the axial dimensions of the magnetostrictive torque sensor. Another advantage of the proposed magnetostrictive torque sensor is its ability to calculate and monitor uniform and linear interference field gradients in the axial direction. Using at least four sensors provides another advantage: eliminating certain nonlinear interference field gradients in the axial direction or reducing the errors they produce.

[0004] The dependent claims illustrate preferred extensions of the invention.

[0005] Preferably, at least two of the at least three magnetic field sensors, and especially the at least three magnetic field sensors, are arranged relative to the at least one magnetized region such that the at least two magnetic field sensors, and especially the at least three magnetic field sensors, are configured to detect the magnetic flux density component of the magnetic field in the direction of the respective at least one measuring axis, the magnetic field being generated by the at least one magnetized region when the shaft is subjected to torsional stress.

[0006] The shaft can be constructed, in particular, as a hollow shaft.

[0007] When the shaft is subjected to a torque load, the magnetic flux density of the magnetic field generated by at least one magnetized region of the shaft is proportional at each location to the torque applied to the shaft. This magnetic field can also be referred to as a useful field within the scope of this invention.

[0008] In the presence of a magnetic interference field in the environment surrounding the shaft or the magnetostrictive magnetic sensor, the magnetic flux density detectable by the at least three magnetic field sensors includes the magnetic field (useful field) generated by the at least one magnetized region when the shaft is under torque load, and the magnetic interference field. Here, the measurement signal of the respective magnetic field sensor includes the useful field magnetic flux density at the location of the respective magnetic field sensor, proportional to the torque applied to the shaft, and the magnetic flux density of the superimposed magnetic interference field. If no magnetic interference field exists in the environment surrounding the shaft or the magnetostrictive magnetic sensor, the measurement signal of the respective magnetic field sensor when the shaft is under torque stress includes only the torque-proportional magnetic flux density of the useful field generated at the location of the respective magnetic field sensor.

[0009] In particular, the at least one measurement signal from the first magnetic field sensor, the at least one measurement signal from the second magnetic field sensor, and the at least one measurement signal from the third magnetic field sensor are offset-cleared measurement signals. Offset clearing is advantageously performed in a state of no torque and no interference field.

[0010] The aforementioned interference field compensation characteristics (for torque calculation) are fully obtained, remaining independent of the initial positioning tolerances of the entire / assembly of the at least three magnetic field sensors relative to the shaft, and therefore also independent of the initial magnetization tolerances of the at least one magnetized region of the shaft. The reason for this is explained in the present invention. It allows all sensors to see arbitrary (and therefore different) (but torque-proportional) useful fields, and not two sensors must see the same useful field to achieve the purpose.

[0011] It should be noted that, within the scope of this invention, the magnetoelastic torque sensor can also be referred to as a magnetoelastic torque sensor arrangement. Correspondingly, within the scope of this invention, the magnetic field sensor can also be referred to as a magnetic field sensor element.

[0012] Within the scope of this invention, the shaft can also be referred to as a magnetoelastic shaft. "Magnetoelastic" means that the mechanical tension generated within the shaft due to mechanical stress causes a change in its magnetization. In other words, the magnetoelastic torque sensor is based on the inverse magnetostrictive effect.

[0013] The statement "the shaft has an axial direction" specifically means that the shaft extends in the axial direction.

[0014] The magnetoelastic torque sensor can preferably be constructed or manufactured as a single unit, wherein all components of the torque sensor, or magnetic field sensor, shaft, and analysis and processing unit, are arranged in a single housing. Alternatively, at least three magnetic field sensors, a shaft having at least one magnetized region (magnetoelastic shaft), and the previously described analysis and processing unit can be combined with each other to function as a magnetoelastic torque sensor according to the invention without introducing these components into a single housing.

[0015] According to a preferred embodiment of the present invention, the at least one measuring axis of the first magnetic field sensor and / or the at least one measuring axis of the second magnetic field sensor and / or the at least one measuring axis of the third magnetic field sensor can respectively include measuring axes parallel in the axial direction or radial direction of the shaft. Here, the at least one measuring signal of the first magnetic field sensor includes a first measuring signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the first magnetic field sensor in the axial direction or radial direction of the shaft, and / or, the at least one measuring signal of the second magnetic field sensor includes a second measuring signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the second magnetic field sensor in the axial direction or radial direction of the shaft, and / or, the at least one measuring signal of the third magnetic field sensor includes a third measuring signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the third magnetic field sensor in the axial direction or radial direction of the shaft.

[0016] According to an alternative configuration of the invention, the at least one measuring axis of the first magnetic field sensor and / or the at least one measuring axis of the second magnetic field sensor and / or the at least one measuring axis of the third magnetic field sensor can each include two or three measuring axes orthogonally oriented relative to each other. Here, the at least one measuring signal of the first magnetic field sensor can include two or three measuring signals, and / or, the at least one measuring signal of the second magnetic field sensor can include two or three measuring signals, and / or, the at least one measuring signal of the third magnetic field sensor can include two or three measuring signals, wherein the component of the magnetic flux density at the corresponding position of the magnetic field sensor in the axial or radial direction of the axis can be determined by the two or three measuring signals of the respective magnetic field sensor. The determination of the component of the magnetic flux density at the corresponding position of the magnetic field sensor in the axial or radial direction of the axis can preferably be achieved by means of an analysis and processing unit.

[0017] In particular, the at least three magnetic field sensors are preferably uniaxial or multiaxial, especially triaxial, wherein the at least three magnetic field sensors are advantageously placed on a straight line parallel to the axial direction, wherein at least one measuring axis of the respective magnetic field sensor is oriented in the axial direction. Alternatively, at least one measuring axis of the respective magnetic field sensor is oriented in the radial direction. Alternatively, two measuring axes of the respective magnetic field sensor are orthogonal to each other and orthogonal to the radial direction, such that they can be used to determine the component of the magnetic flux density in the axial direction of the magnetic field. Alternatively, three measuring axes of the respective magnetic field sensor are orthogonal to each other, such that they can be used to determine the component of the magnetic flux density in the axial and / or radial directions of the magnetic field, wherein the orientation of the respective magnetic field sensor is freely selectable. It should be noted that a uniaxial magnetic field sensor is sufficient to eliminate uniform interference fields and linear interference field gradients. By implementing the use of a uniaxial magnetic field sensor, a magnetostrictive torque sensor with a low overall cost can be realized. For example, the magnetic field sensor can be constructed as a fluxgate coil, which is extremely cost-effective. The monitoring function of the magnetostrictive torque sensor is supplemented by the use of a multi-axis magnetic field sensor, which has the advantage of providing multiple pieces of information. Preferably, the analysis and processing unit is configured to additionally use the sensitivity of the magnetostrictive torque sensor to determine the torque applied to the shaft. In other words, the analysis and processing unit is configured to determine the torque applied to the shaft by means of at least one measurement signal from the first magnetic field sensor, at least one measurement signal from the second magnetic field sensor, at least one measurement signal from the third magnetic field sensor, the ratio of the distance in the axial direction between the second and third magnetic field sensors to the distance in the axial direction between the first and second magnetic field sensors, and the sensitivity of the magnetostrictive torque sensor. "Sensitivity of the magnetostrictive torque sensor" is understood as the change in the value of the output parameter (i.e., torque) relative to the change in the value of the input parameter (i.e., magnetic flux density) that causes it. Within the scope of the invention, the sensitivity of the magnetostrictive torque sensor can also be referred to as the total sensitivity.

[0018] Preferably, the analysis and processing unit is configured to determine the torque applied to the shaft using the following formula: Here: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density at the location of the first magnetic field sensor, expressed in μT, along the axial or radial direction. • B SE2It is the component of the magnetic flux density at the location of the second magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • B SE3 It is the component of the magnetic flux density at the location of the third magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • s 13 This is the sensitivity of a magnetostrictive torque sensor, measured in Nm / μT.

[0019] The proposed formula (1), and especially the difference it contains, can eliminate the gradients of uniform and linear interference fields, thereby enabling accurate determination of torque based on the measurement signals of the first, second, and third magnetic field sensors.

[0020] According to another preferred embodiment of the invention, the analysis processing unit is configured to determine the torque applied to the shaft using the following formula: Where k≠1, In particular, 0.9 ≤ k < l or l < k ≤ 1.1. Here: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density at the location of the first magnetic field sensor, expressed in μT, along the axial or radial direction. • B SE2 It is the component of the magnetic flux density at the location of the second magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • B SE3 It is the component of the magnetic flux density at the location of the third magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • s 13The sensitivity of the magnetostrictive torque sensor is measured in Nm / μT, ​​and • k is a predetermined weighting factor that, when determining torque, can reduce the error caused by the nonlinear interference field share, even when there is a nonlinear interference field share caused by the gradient of a nonlinear interference field with the same structure in the environment surrounding the shaft or magnetoelastic torque sensor.

[0021] In other words, by incorporating the weighting factor "k" into the torque determination according to the proposed formula (2), it is possible to correlate it with the distance ratio d. 23 / d 12 The deviation allows for a reduction in errors caused by the nonlinear interference field proportion when a nonlinear interference field exists in the environment surrounding the axis, or the magnetoelastic torque sensor. This is particularly true in target applications where the nonlinear interference field gradient in the region of the magnetoelastic torque sensor has a consistently consistent structure. Conversely, in applications where the assumption of a consistently consistent nonlinear interference field gradient may lead to errors in torque calculations due to the possibility of variable structures in the interference field gradient, and in inappropriate locations and environments, the errors may be larger than those in Equation (1), allowing for a further reduction in the maximum possible error in such applications using Equation (2).

[0022] The weighting factor k can be selected or predetermined / selected or predetermined based on the application.

[0023] What can be achieved here is: through mathematical optimization. dMSE(k) / dk = 0 The weighting factor k is finely adjusted to minimize the mean squared error (MSE). Therefore, for example, the point "0 Nm" can be optimized to minimize the error by some choice of scenarios with different disturbance effects, or it can be optimized only for a single disturbance field scenario.

[0024] If only a uniform disturbance field and / or a disturbance field with a linear share and / or only a negligible nonlinear disturbance field share exists in the region of the magnetoelastic torque sensor, or if only such a disturbance field is expected in the application, then in order to determine the torque acting on the shaft of the magnetoelastic torque sensor, formula (1) is preferred over formula (2), as in applications where the location and environment are variable, where the nonlinear disturbance field gradient of the same construction cannot be guaranteed at all times.

[0025] However, it should be noted that the torque acting on the shaft can also be determined with sufficient accuracy in Equation (1), even in the presence of a disturbance field with a nonlinear component in the surrounding environment. The advantage of Equation (1) is that it fully compensates for the linear disturbance field component, independent of the application and operating environment. Since the nonlinear component is generally small compared to a uniform and linear component, the error in Equation (1) caused by the nonlinear component is so small that the torque can be determined with sufficient / high accuracy.

[0026] In particular, unlike Equation (1), Equation (2) no longer aims to compensate for all interference field scenarios (uniform and linear fractions) as completely as possible, but instead achieves optimization for one or more similar interference field scenarios, which can be compensated better than using Equation (1) because the nonlinear fraction is also partially compensated. Here, interference field scenarios that are different from those optimized interference field scenarios will result in larger errors than when using Equation (1). All interference field scenarios “without” a nonlinear fraction can also be compensated without error using Equation (1) in a favorable manner.

[0027] In applications of magnetoelastic torque sensors in vehicles, particularly electric and / or human-powered vehicles, especially electric bicycles, various significantly different interference field scenarios arise during operation simply due to changes in location during travel (without maintaining the same operating environment). This diversity leads to optimization resulting in k=1 (as in Equation (1)) or k≠1 when weighting optimization for each interference field scenario, where the maximum possible error thus increases using Equation (2). For this reason, Equation (1) is more advantageous for the applications already described. In applications with similar or less drastically different interference field scenarios, Equation (2) can be more advantageous.

[0028] In a favorable manner, the sensitivity of the magnetoelastic torque sensor is determined by means of two-point calibration in the absence of a disturbance field and after offset clearance. In particular, the sensitivity of Equation (1) is obtained according to the following formula: In particular, the sensitivity of formula (2) is obtained according to the following formula: Here: • M1 is the torque in Nm at the first point of the two-point calibration. • M2 is the torque measured in Nm at the second point of the two-point calibration. • B SEa (Mb The measurement signal is measured by a magnetic sensor at point "b" with two-point calibration, in units of "μT". Wherein, for the first magnetic field sensor, a=1; for the second magnetic field sensor, a=2; and for the third magnetic field sensor, a=3; and For the first point of the two-point calibration, b=1; and for the second point of the two-point calibration, b=2. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • k is a predetermined weighting factor that, when determining torque, can reduce the error caused by the nonlinear interference field share, even when there is a nonlinear interference field share caused by the gradient of a nonlinear interference field with the same structure in the environment surrounding the shaft or magnetoelastic torque sensor.

[0029] It should be noted that the notation "..." in the formula above indicates that the formula continues on the next line. Within the scope of this invention, this applies to all formulas containing the notation "...". Here, the standard order of operators applies to arithmetic operations.

[0030] The following formulas (1b) and (1c) are equivalent to formula (1) and are derived from formula (1) by transformation: ,in, (1b) ,in, (1c) Preferably, the first magnetic field sensor, the second magnetic field sensor, and the third magnetic field sensor are arranged relative to each other and relative to the at least one magnetized region such that one of the following two conditions is satisfied: ,in, (4a) ,in, (4b).

[0031] In particular, the first magnetic field sensor, the second magnetic field sensor, and the third magnetic field sensor are arranged relative to each other, and the at least one magnetized region is arranged such that one of the following two conditions is satisfied: ,in, (5a) ,in, (5b).

[0032] Here: • N SE1 It is a predetermined component, in μT, of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the first magnetic field sensor, caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE2 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the second magnetic field sensor, in units of "μT," caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE3 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the third magnetic field sensor, in units of "μT", caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor.

[0033] exist( d 23 / d 12 )≤1 and ( d 12 / d 23 The distinction between cases with values ​​less than 1 ensures that the effective total sensitivity is considered to be without artificial amplification.

[0034] Advantageously, the predetermined magnetic flux density mentioned above is a magnetic flux density that has been offset-cleared and is free of interference fields. Preferably, the sum of the axial distance between the first and second magnetic field sensors and the axial distance between the second and third magnetic field sensors is greater than or equal to 4 mm and less than 20 mm. In other words, the axial distance between the first and third magnetic field sensors is preferably greater than or equal to 4 mm and less than 20 mm. Thus, the magnetostrictive torque sensor can be compactly constructed in the axial direction. Here, the at least three magnetic field sensors can particularly include exactly the first, second, and third magnetic field sensors.

[0035] Particularly preferred is that the at least three magnetic field sensors include a first magnetic field sensor, a second magnetic field sensor, a third magnetic field sensor, and a fourth magnetic field sensor. Here, the third magnetic field sensor is arranged axially between the second and fourth magnetic field sensors. The analysis and processing unit is configured to: detect at least one measurement signal from the fourth magnetic field sensor, and additionally use the at least one measurement signal from the fourth magnetic field sensor, and the ratio of the axial distance between the second and third magnetic field sensors to the axial distance between the third and fourth magnetic field sensors, in order to determine the torque applied to the shaft. In other words, the analysis and processing unit is configured to: detect at least one measurement signal from the fourth magnetic field sensor, determine the torque applied to the shaft by means of the at least one measurement signal from the first magnetic field sensor, the at least one measurement signal from the second magnetic field sensor, the at least one measurement signal from the third magnetic field sensor, the at least one measurement signal from the fourth magnetic field sensor, and the ratio of the axial distance between the second and third magnetic field sensors to the axial distance between the first and second magnetic field sensors, and by means of the ratio of the axial distance between the second and third magnetic field sensors to the axial distance between the third and fourth magnetic field sensors. By taking into account the distance between the magnetic field sensors relative to each other and the corresponding weighting or scaling of the measurement signals of the magnetic field sensors, the measurement signals can be combined to eliminate uniform and linear interference field gradients and eliminate or minimize nonlinear interference field gradients when calculating torque. This is also true in applications where the location and environment are variable, where the nonlinear interference field gradients in the environment surrounding the shaft or magnetoelastic torque sensor cannot be guaranteed to be consistently the same.

[0036] In particular, the measurement signal from the fourth magnetic field sensor is a offset-cleared measurement signal. Offset clearing is performed advantageously in a state of no torque and no interfering field.

[0037] The at least one measuring axis of the fourth magnetic field sensor preferably includes a measuring axis parallel to the axial or radial direction of the shaft, wherein the at least one measuring signal of the fourth magnetic field sensor includes a fourth measuring signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the fourth magnetic field sensor in the axial or radial direction of the shaft.

[0038] According to an alternative configuration of the invention, the at least one measurement axis of the fourth magnetic field sensor comprises two or three measurement axes orthogonally oriented relative to each other, wherein the at least one measurement axis of the fourth magnetic field sensor comprises two or three measurement signals, which can determine the component of the magnetic flux density of the magnetic field at the location of the fourth magnetic field sensor in the axial or radial direction of the axis. The component of the magnetic flux density of the magnetic field at the location of the fourth magnetic field sensor in the axial or radial direction of the axis can preferably be determined by means of an analysis and processing unit.

[0039] Preferably, the analysis and processing unit is configured to determine the torque applied to the shaft using the following formula: Where 0 ≤ k ≤ l. Here: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density at the location of the first magnetic field sensor, expressed in μT, along the axial or radial direction. • B SE2 It is the component of the magnetic flux density at the location of the second magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • B SE3 It is the component of the magnetic flux density at the location of the third magnetic field sensor, expressed in μT, along the axial or radial direction of the magnetic field. • B SE4 It is the fourth measurement signal, measured in μT. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • d 34 It is the distance between the third and fourth magnetic field sensors, measured in mm. • s 14 The sensitivity of the magnetostrictive torque sensor is measured in Nm / μT, ​​and • k is a weighting factor that optimizes the compensation characteristics (complete elimination) of the nonlinear interference field share for an application-specific purpose, or in general, minimizes the worst-case error caused by the nonlinear interference field share.

[0040] By using formula (6) and the subtraction it contains, the portion of the interference field caused by the uniform interference field and the superimposed linear interference field gradient can be eliminated when calculating the torque. Specifically, regardless of the value of the chosen weighting factor k, as long as 0 ≤ k ≤ 1. The error caused by the nonlinear interference field gradient can be eliminated or minimized according to the chosen k. Therefore, based on the measurement signals of the first, second, third, and fourth magnetic field sensors, even in the presence of a nonlinear interference field gradient in the environment surrounding the magnetoelastic torque sensor, the torque can be determined more accurately.

[0041] Advantageously, the sensitivity of the magnetoelastic torque sensor is determined by means of two-point calibration in the absence of a disturbance field and after offset clearance. Specifically, the sensitivity is obtained according to the following formula: Here: • M1 is the torque in Nm at the first point of the two-point calibration. • M2 is the torque measured in Nm at the second point of the two-point calibration. • B SEa (M b The measurement signal is measured by the magnetic sensor "a" at point "b" which is calibrated at two points, in μT. Wherein, for the first magnetic field sensor, a=1; for the second magnetic field sensor, a=2; for the third magnetic field sensor, a=3; and for the fourth magnetic field sensor, a=4; and For the first point of the two-point calibration, b=1; and for the second point of the two-point calibration, b=2. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • d 34 It is the distance between the third and fourth magnetic field sensors, measured in mm. • k is the weighting factor described in the previous reference formula (6).

[0042] Preferably, the first magnetic field sensor, the second magnetic field sensor, the third magnetic field sensor, and the fourth magnetic field sensor are arranged relative to each other and relative to the at least one magnetized region, such that the following condition is satisfied: Where 0≤k≤1.

[0043] In particular, the first magnetic field sensor, the second magnetic field sensor, the third magnetic field sensor, and the fourth magnetic field sensor are arranged relative to each other and relative to the at least one magnetized region such that the following condition is satisfied: Where 0≤k≤1.

[0044] Here: • N SE1 It is a predetermined component, in μT, of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the first magnetic field sensor, caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE2 It is a predetermined component, in μT, of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the second magnetic field sensor, caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE3 It is a predetermined component, in μT, of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the third magnetic field sensor, caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE4 It is a predetermined component, in μT, of the magnetic flux density of the magnetic field generated by the at least one magnetized region at the location of the fourth magnetic field sensor, caused by the stress on the shaft due to the maximum torque that can be measured by the magnetoelastic torque sensor. • d 12 It is the distance between the first magnetic field sensor and the second magnetic field sensor, measured in mm. • d 23 It is the distance between the second and third magnetic field sensors, measured in mm. • d 34 It is the distance between the third and fourth magnetic field sensors, measured in mm. • k is the weighting factor described in the previous reference formula (6).

[0045] In particular, the predetermined magnetic flux density mentioned above is a magnetic flux density that has been offset-cleared and is free of interference fields.

[0046] Preferably, the sum of the axial distance between the first and second magnetic field sensors, the axial distance between the second and third magnetic field sensors, and the distance between the third and fourth magnetic field sensors is greater than or equal to 6 mm and less than 20 mm. In other words, the axial distance between the first and fourth magnetic field sensors is preferably greater than or equal to 6 mm and less than 20 mm. Therefore, the magnetostrictive torque sensor is compactly constructed in the axial direction. Here, the at least three magnetic field sensors can specifically include the first, second, third, and fourth magnetic field sensors.

[0047] According to an advantageous configuration of the invention, the shaft has only one magnetized region to which the at least three magnetic field sensors are associated. Specifically, a first, second, and third magnetic field sensor, or a first, second, third, and fourth magnetic field sensor, are associated with the magnetized region.

[0048] According to an alternative advantageous configuration of the invention, the shaft has only a first magnetized region and a second magnetized region, wherein the first magnetized region and the second magnetized region have opposite magnetizations. In other words, the shaft preferably has only two magnetized regions with opposite magnetizations. The first magnetized region and the second magnetized region can have the same magnetization numerically. However, it is possible that the magnetization values ​​of the first magnetized region and the second magnetized region are different.

[0049] Preferably, the first and second magnetic field sensors are located within the first magnetization region, and the third magnetic field sensor is located within the second magnetization region. Alternatively, preferably, the first and second magnetic field sensors can be located within the first magnetization region, and the third and fourth magnetic field sensors can be located within the second magnetization region.

[0050] The statement “a magnetic field sensor is associated with a magnetization region” specifically means that the magnetic field sensor is configured to detect one or more components of the magnetic flux density of the magnetic field generated by the magnetization region when the shaft is subjected to torque stress.

[0051] The first magnetic field sensor and / or the second magnetic field sensor and / or the third magnetic field sensor and / or the fourth magnetic field sensor can be respectively configured as, for example, a Hall sensor, an AMR sensor (a sensor based on the AMR effect; a sensor based on the anisotropic magnetoresistive effect), a GMR sensor (a sensor based on the GMR effect; a giant magnetoresistive sensor), a fluxgate magnetometer, or a TMR sensor (a tunnel magnetoresistive sensor).

[0052] It should be noted that, within the scope of this invention, the distance between one magnetic field sensor and another magnetic field sensor is advantageously defined as the distance between a point (especially the center of the sensor) of the one magnetic field sensor and a corresponding point (especially the center of the sensor) of the other magnetic field sensor.

[0053] Within the scope of this invention, the term "magnetized region" can also be referred to as "magnetized track" or "magnetized trajectory".

[0054] The present invention also relates to a vehicle having a previously described magnetoelastic torque sensor.

[0055] The vehicle in particular is capable of being operated electrically and / or manually and has a crank drive mechanism. Here, a magnetostrictive torque sensor is advantageously arranged on the crank drive mechanism and is particularly configured to detect the torque applied to the crank drive mechanism by the driver through his manual power.

[0056] Furthermore, the present invention relates to a method for determining torque when using a previously described magnetoelastic torque sensor. The method includes the steps of: detecting at least one measurement signal from a first magnetic field sensor, detecting at least one measurement signal from a second magnetic field sensor, detecting at least one measurement signal from a third magnetic field sensor, and determining the torque applied to a shaft by means of the at least one measurement signal from the first magnetic field sensor, the at least one measurement signal from the second magnetic field sensor, the at least one measurement signal from the third magnetic field sensor, and the ratio of the distance in the axial direction between the second and third magnetic field sensors to the distance in the axial direction between the first and second magnetic field sensors. Here, the advantages implemented with reference to the previously described magnetoelastic torque sensor are also given.

[0057] In other words, the present invention relates to a method for determining torque, the method comprising the steps of: detecting at least one measurement signal from a first magnetic field sensor, detecting at least one measurement signal from a second magnetic field sensor, and detecting at least one measurement signal from a third magnetic field sensor, wherein the second magnetic field sensor is arranged axially between the first and third magnetic field sensors, and each magnetic field sensor has at least one measurement axis and is configured to detect a component of magnetic flux density of a magnetic field in the direction of the at least one measurement axis. At least one of the magnetic field sensors is arranged relative to at least one magnetized region of the shaft such that the magnetic field sensor is configured to detect a component of magnetic flux density of a magnetic field in the direction of the respective at least one measurement axis, the magnetic field being capable of being generated by the magnetized region when the shaft is subjected to torque stress. Furthermore, the method includes the step of determining the torque applied to the shaft by means of the at least one measurement signal from the first magnetic field sensor, the at least one measurement signal from the second magnetic field sensor, the at least one measurement signal from the third magnetic field sensor, and the ratio of the distance in the axial direction between the second and third magnetic field sensors to the distance in the axial direction between the first and second magnetic field sensors.

[0058] It should be noted that the features described above for the magnetoelastic torque sensor can also be described as methodological features.

[0059] The analysis and processing unit and the magnetic field sensor can be advantageously connected to each other in an information technology-based / digital or analog manner, depending on the type of magnetic field sensor. In other words, the interface between the analysis and processing unit and the magnetic field sensor can be implemented digitally or analogly, depending on the type of magnetic field sensor. Attached Figure Description

[0060] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein identical or functionally identical components are respectively provided with the same reference numerals. In the drawings: Figure 1 A simplified schematic diagram of a magnetoelastic torque sensor according to a first embodiment of the present invention. Figure 2 From Figure 1 A simplified schematic diagram of the shaft of the magnetostrictive torque sensor when the shaft is not under torque load. Figure 3 From Figure 2 A simplified schematic diagram of the shaft of the magnetostrictive torque sensor when the shaft is subjected to a torque load. Figure 4 A graph used to represent an example of the magnetic interference field in the environment surrounding a magnetoelastic torque sensor. Figure 5A graph showing the distribution of the axial component of the magnetic field along the shaft of an exemplary magnetoelastic torque sensor according to the first embodiment, which can be generated when the shaft is subjected to a torque load and can be detected by the magnetic field sensor of the torque sensor. Figure 6 An electric bicycle having a magnetoelastic torque sensor according to the first embodiment, Figure 7 A simplified schematic diagram of a magnetoelastic torque sensor according to a second embodiment of the present invention. Figure 8 From Figure 7 A simplified schematic diagram of the shaft of the magnetostrictive torque sensor when the shaft is not under torque load. Figure 9 A graph showing the distribution of the axial component of the magnetic field along the shaft of the first exemplary magnetoelastic torque sensor according to the second embodiment, which can be generated when the shaft is subjected to a torque load and can be detected by the magnetic field sensor of the torque sensor. Figure 10 A graph showing the distribution of the axial component of the magnetic field along the shaft of the second exemplary magnetoelastic torque sensor according to the second embodiment, which can be generated when the shaft is subjected to a torque load and can be detected by the magnetic field sensor of the torque sensor. Figure 11 A graph showing the distribution of the axial component of the magnetic field along the shaft of the third exemplary magnetoelastic torque sensor according to the second embodiment, which can be generated when the shaft is subjected to a torque load and can be detected by the magnetic field sensor of the torque sensor. Figure 12 A simplified schematic diagram of a magnetoelastic torque sensor according to a third embodiment of the present invention, and Figure 13 A simplified schematic diagram of a magnetoelastic torque sensor according to a fourth embodiment of the present invention. Detailed Implementation

[0061] The following is for reference. Figures 1 to 5 A magnetoelastic torque sensor 10 according to a first embodiment of the present invention is described in detail.

[0062] As from Figure 1 As can be seen, the magnetostrictive torque sensor 10 includes a magnetostrictive shaft 5, a first magnetic field sensor 1, a magnetic field sensor 2, a third magnetic field sensor 3, and an analysis and processing unit 6.

[0063] A magnetization region 51 is formed in a shaft 5 that is advantageously constructed into a cylindrical shape. The magnetization region 51 corresponds to the portion of the shaft 5 that has already been magnetized. However, it is also possible that the magnetization region 51 is provided by an additional magnetizing element (in particular by a magnetizing ring) surrounding the shaft 5.

[0064] It should be noted that in this embodiment, the shaft 5 only includes the magnetized region 51, and the magnetostrictive torque sensor 10 does not include any other magnetic field sensors besides the first magnetic field sensor 1, the second magnetic field sensor 2 and the third magnetic field sensor 3.

[0065] The axial direction 111, radial direction 112, and circumferential direction 113 are defined by shaft 5. Shaft 5 extends in the axial direction 111. The axial direction 111, radial direction 112, and circumferential direction 113 of shaft 5 can also be referred to as the axial direction, radial direction, and circumferential direction of the magnetoelastic torque sensor 10 within the scope of this invention.

[0066] The first magnetic field sensor 1, the second magnetic field sensor 2, and the third magnetic field sensor 3 are advantageously arranged at the same position relative to the axis 5 in both the radial direction 112 and the circumferential direction 113. Each of the three sensors has at least one measuring axis and is configured to detect the component of the magnetic flux density of the magnetic field in the direction of the at least one measuring axis. In the axial direction 111, the first magnetic field sensor 1, the second magnetic field sensor 2, and the third magnetic field sensor 3 are arranged at different positions relative to the axis 5.

[0067] If from Figure 1 As derived from this, the second magnetic field sensor 2 is positioned between the first magnetic field sensor 1 and the third magnetic field sensor 3.

[0068] Specifically, the first magnetic field sensor 1 and the second magnetic field sensor 2 are arranged at a distance of 12 from each other in the axial direction 111. Furthermore, the third magnetic field sensor 3 is arranged at a distance of 23 from the second magnetic field sensor 2 in the axial direction 111.

[0069] Here, the sum of the distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 in the axial direction 111 and the distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 in the axial direction 111 is greater than or equal to 4 mm and less than 20 mm.

[0070] The first magnetic field sensor 1, the second magnetic field sensor 2, and the third magnetic field sensor 3 are arranged relative to each other and relative to the magnetization region 51 of the axis 5, such that one of the following two conditions is satisfied: ,in, , ,in, .

[0071] Here: • N SE1It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the first magnetic field sensor 1, which is in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • N SE2 It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the second magnetic field sensor 2, in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • N SE3 It is a predetermined component of the magnetic flux density of the magnetic field 5 generated by the magnetized region 51 at the location of the third magnetic field sensor 3, which is in "μT" and is caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10.

[0072] In a favorable manner, the predetermined magnetic flux density mentioned above is an offset-bereinigt magnetic flux density without interference fields.

[0073] In particular, three magnetic field sensors 1, 2, and 3 are associated with the magnetization region 51. In other words, the three magnetic field sensors 1, 2, and 3 are arranged relative to the magnetization region 51 such that the magnetic field sensors 1, 2, and 3 are respectively configured to detect, in the axial direction 111, the component of the magnetic flux density of the magnetic field generated by the magnetization region 51 when the shaft 5 is subjected to torsional stress.

[0074] The following reference Figure 2 and 3 This will explain how the magnetic field is generated when shaft 5 is subjected to a torque load.

[0075] exist Figure 2 The figure shows the shaft 5 of the magnetostrictive torque sensor 10 when there is no torque load. As can be seen from the figure, the magnetized region 51 of the shaft 5 has closed field lines 54 that run in the circumferential direction 113 in the shaft 51.

[0076] On the other hand, Figure 3The diagram shows shaft 5 under torque loading. The torque applied to shaft 5, or magnetized region 51, results in mechanical stress in shaft 5. Through magnetoelastic interactions occurring in the magnetized region 51 of shaft 5, the force lines 54 rotate in the direction of stress. Thus, the force lines 54 spiral around shaft 5. As a result, the force lines 54 reaching the end 512 of magnetized region 51 leave shaft 5 and return to the beginning 511 of magnetized region 51. This generates a magnetic field in a region outside shaft 5, which is always oriented along shaft 5. This magnetic field is called the useful field. Precisely at the center of magnetized region 51, the useful field is parallel to shaft 5, while at the edges of magnetized region 51, the portion of the useful field perpendicular to shaft 5 increases. Figure 1 and 3 The magnetic flux density of the useful field presented by the field force line 55, or the useful field outside the axis 5, is proportional to the torque applied to the axis 5 at each location.

[0077] The magnetic flux density of the useful field outside shaft 5 can be detected by magnetic field sensors 1, 2, and 3, which are respectively configured to output measurement signals. If a magnetic interference field exists in the environment surrounding shaft 5 or the torque-elastic magnetic sensor 10, then when shaft 5 is under torque load, the measurement signal of each magnetic field sensor 1, 2, and 3 includes not only the corresponding magnetic flux density of the generated useful field, but also the magnetic flux density of the magnetic interference field superimposed at the location of the corresponding magnetic field sensor 1, 2, and 3.

[0078] Specifically, the analysis and processing unit 6 is configured to detect the first measurement signal of the first magnetic field sensor 1, the second measurement signal of the second magnetic field sensor 2, and the third measurement signal of the third magnetic field sensor 3. For this purpose, the analysis and processing unit 6 is connected to the three magnetic field sensors 1, 2, and 3, particularly in terms of information technology.

[0079] In particular, the first, second, and third measurement signals are offset-cleared measurement signals. Offset clearing is performed advantageously in a state of no torque and no interference field.

[0080] In order to determine the torque applied to the shaft 5, the analysis and processing unit 6 is configured to use the first measurement signal, the second measurement signal, the third measurement signal, the ratio of the distance 23 in the axial direction 111 between the second magnetic field sensor 23 and the third magnetic field sensor 3 to the distance 12 in the axial direction 111 between the first magnetic field sensor 1 and the second magnetic field sensor 2, and the sensitivity of the magnetostrictive torque sensor 10.

[0081] Here, the first measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the first magnetic field sensor, the second measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the second magnetic field sensor, and the third measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the third magnetic field sensor.

[0082] In particular, the analysis and processing unit 6 is configured to determine the torque applied to the shaft 5 using the following formula: Here, • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density in the axial direction at the location of the first magnetic field sensor, expressed in μT. • B SE2 It is the component of the magnetic flux density in the axial direction at the location of the second magnetic field sensor, expressed in μT. • B SE3 It is the component of the magnetic flux density along the axial direction at the location of the third magnetic field sensor, expressed in μT. • d 12 The distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 is measured in mm. • d 23 The distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 is measured in mm. • S 13 The sensitivity of the magnetostrictive torque sensor 10 is expressed in Nm / μT.

[0083] By employing the proposed arrangement of magnetic field sensors 1, 2, and 3, and by calculating the torque applied to the shaft 5 of the magnetoelastic torque sensor 10, the uniform and linear interference field gradients in the axial direction 111 can be directly and without approximation during calculation. Furthermore, these directly eliminated interference fields can be calculated without approximation and can be used for potential monitoring functions. (See below for further details.) Figure 4 The calculation of the eliminated interference field is explained in more detail.

[0084] Small, generally negligible errors in torque calculation can still occur, for example, due to nonlinear gradients, because the calculation formula previously described makes the assumption that the nonlinear disturbance field fraction is zero. However, the nonlinear fraction is numerically negligible compared to the uniform disturbance field and linear disturbance field gradient typically present in the environment surrounding the magnetoelastic torque sensor 10.

[0085] To further reduce the small error when using measurement signals from only three magnetic field sensors (i.e., magnetic field sensors 1, 2, and 3) to calculate the torque applied to the shaft 5 in the presence of a nonlinear interference field in the environment surrounding the shaft 5 of the magnetoelastic torque sensor 10, the analysis processing unit 6 can also be configured to determine the torque applied to the shaft 5 using the following formula: Where 0.9 ≤ k<1 or 1 <k ≤1.1。

[0086] The difference between the two formulas lies in the use of a predetermined weighting factor k in the second formula. By incorporating this weighting factor into the torque calculation, the error caused by the nonlinear interference field fraction in the axial direction 111 can be reduced when determining the torque, especially in the case of a nonlinear interference field fraction present in the environment surrounding shaft 5, or the magnetoelastic torque sensor 10.

[0087] In other words, by using a predetermined weighting factor k—in the case where there is a nonlinear disturbance field gradient with the same configuration in the target application in the region of the magnetoelastic torque sensor 10—the small error that would occur when using the first formula can be further reduced. However, in applications where the assumption of a nonlinear disturbance field gradient with the same configuration may lead to an inappropriate location and variable environment due to the possibility of variable configuration of the disturbance field gradient, the error in torque calculation may be larger than that of the first formula. Therefore, in such applications, the first formula without a predetermined weighting factor k is the preferred choice in order to minimize the maximum possible error.

[0088] The sensitivity of the magnetoelastic torque sensor 10 can be determined by means of two-point calibration in the absence of a disturbance field and after offset clearance. In particular, the sensitivity is determined by the general part of this specification according to Formula 3a or Formula 3b.

[0089] The first magnetic field sensor 1 and / or the second magnetic field sensor 2 and / or the third magnetic field sensor 3 can be respectively configured as, for example, a Hall sensor, an AMR sensor (a sensor based on the AMR effect; a sensor based on the anisotropic magnetoresistive effect), a GMR sensor (a sensor based on the GMR effect; a giant magnetoresistive sensor), a fluxgate magnetometer, or a TMR sensor (a tunnel magnetoresistive sensor).

[0090] Figure 4 A graph is shown to represent an example of the magnetic interference field in the environment surrounding the magnetoelastic torque sensor 10.

[0091] The x-axis 200 represents the distance along axis 5 in the axial direction 111, measured from the origin 202, in mm, while the y-axis 201 represents the component of the magnetic flux density of the disturbance field in the axial direction (111), in μT. The zero value at the origin 202 in the x-axis 200 corresponds to the beginning of axis 5.

[0092] from Figure 4 As can be seen, the magnetic interference field between the first magnetic field sensor 1 and the third magnetic field sensor 3 has a uniform share 203, which is defined with respect to the magnetic field sensor 1. That is, this uniform share 203 exists in the axial direction 111 at the positions of the first magnetic field sensor 1, the second magnetic field sensor 2, and the third magnetic field sensor 3.

[0093] By defining a uniform fraction 203 as a reference for the first magnetic field sensor 1, only the uniform fraction 203 exists at the location of the first magnetic field sensor 1. A linear interference field gradient also exists between the first magnetic field sensor 1 and the third magnetic field sensor 3, such that at the location of the second magnetic field sensor 2, there are a uniform fraction 203 and a linear fraction 204 in the axial direction 111, and at the location of the third magnetic field sensor 3, there are a uniform fraction 203, a linear fraction 204, and another linear fraction 205 in the axial direction 111.

[0094] As from Figure 4 It is also found that there is another portion 206 of the interference field gradient between the second magnetic field sensor 2 and the third magnetic field sensor 3, such that a nonlinear interference field gradient exists between the first magnetic field sensor 1 and the third magnetic field sensor 3 in an aggregate manner. By defining the measurable gradient between the first magnetic field sensor 1 and the second magnetic field sensor 2 as purely linear, in order to map the nonlinear interference gradient between the first magnetic field sensor 1 and the third magnetic field sensor 3 to the linear portion 205 between the second magnetic field sensor 2 and the third magnetic field sensor 3, a portion 206 should be added at the location of the third magnetic field sensor 3. Therefore, at the location of the third magnetic field sensor 3, a nonlinear portion 206 also exists in the axial direction 111.

[0095] It should be noted that the previously described formula for calculating the torque applied to the shaft 5 of the magnetoelastic torque sensor 10 achieves the elimination or compensation of the interference field in the shaft 5 or the surrounding environment of the magnetoelastic torque sensor 10 in an accurate process (Ablauf) independent of the interference field in the axial direction 111.

[0096] From Figure 4 The various components of the interference field can be obtained using the following formula: in: and Here: • ΔS lin (d 23 ) It is a linear fraction of 205, measured in μT. • ΔS lin (d 12 ) It is a linear fraction of 204, measured in μT. • ΔS lin (d 13 ) It is the total linear fraction of the magnetic interference field at the location of the third magnetic field sensor 3, and this total linear fraction corresponds to the sum of linear fractions 205 and 204, and • ΔS n.l. It is a non-linear share of 206.

[0097] Useful fields in μT N Sea (M 2 ) (Where, for the first magnetic field sensor 1, a=1; for the second magnetic field sensor 2, a=2; and for the third magnetic field sensor 3, a=3) should be determined during calibration (without interference fields and after offset clearing), where torque must be applied. M 2 ≫ 0 Nm.

[0098] In the formula described above for determining the proportion of the interference field, it is necessary to assume that there is no nonlinear interference field gradient, or that the nonlinear interference field gradient is negligible. ΔS x,n.l= 0. The linear disturbance field gradient can be monitored at runtime so that the calculated torque can be declared invalid if a defined limit is exceeded. This is particularly advantageous because as the measured linear disturbance field gradient increases, the maximum possible error in the calculated torque caused by the nonlinear disturbance gradient also increases.

[0099] From Figure 4 The uniform fraction 203 of the interference field can be obtained using the following formula: for N SE2 ≠ N SE3 for N x, SE1 ≠ N x , SE2 By analyzing from Figure 4 The calculated interference field fractions at the locations of magnetic field sensors 1, 2, and 3 are summed accordingly, thus determining the total interference field component at the location of the magnetic field sensor. The aforementioned fractions of the interference field and the corresponding total interference field component can be calculated using the analysis and processing unit 6.

[0100] Figure 5 A graph showing the magnetic flux density of the magnetic field in the axial direction 111 is shown. This magnetic field can be generated when the shaft 52 of the exemplary magnetoelastic torque sensor 10 according to the first embodiment is subjected to a torque load and can be detected by the three magnetic field sensors 1, 2, and 3 of the torque sensor 10.

[0101] The x-axis 207 represents the distance along axis 5 in the axial direction 111, measured from the origin 209, in mm, while the y-axis 208 represents the component of magnetic flux density in the axial direction 111, in μT. The zero value at the origin 209 in the x-axis 207 corresponds to the beginning of axis 5.

[0102] For this exemplary magnetoelastic torque sensor 10, the following applies: ,in, .

[0103] Illustratively, this means that the first slope 210 and the second slope 211 are different from each other. The first slope 210 is the slope of the straight line connecting the point defined by the magnetic flux density of the useful field at the location of the first magnetic field sensor 1 to the point defined by the magnetic flux density of the useful field at the location of the second magnetic field sensor 2. Correspondingly, the second slope 211 is the slope of the straight line connecting the point defined by the magnetic flux density of the useful field at the location of the second magnetic field sensor 2 to the point defined by the magnetic flux density of the useful field at the location of the third magnetic field sensor 3.

[0104] Here, in particular, the first slope 210 is positive, while the second slope 211 is negative.

[0105] Figure 6 A vehicle 100 according to the invention is shown, having a magnetoelastic torque sensor 10 according to a first embodiment.

[0106] The vehicle 100 is a vehicle, particularly an electric bicycle, that can be operated by human power and / or motor power, and is equipped with an electric drive 101 to support the rider's pedaling force. The electric drive 101 is arranged on a crank transmission mechanism 102 having a first crank 103 and a second crank 104 and is powered by a battery 105.

[0107] The magnetostrictive torque sensor 10 can be constructed or manufactured as a unit and fastened to the crank drive mechanism 102 as such a unit. Here, the magnetic field sensors 1, 2 and 3, shaft 5, and analysis and processing unit 6 are advantageously received in a single housing. Alternatively, the magnetic field sensors 1, 2 and 3, shaft 5, and analysis and processing unit 6 can be individually fastened to the vehicle 100 such that they function together as the magnetostrictive torque sensor 10 according to the invention.

[0108] Using the magnetostrictive torque sensor 10 in a vehicle, such as the previously described vehicle 100, is just one possible application of the present invention.

[0109] Figures 7 to 11 A magnetoelastic torque sensor 10 according to a second embodiment of the present invention.

[0110] The difference between the magnetoelastic torque sensor 10 according to the second embodiment and the magnetoelastic torque sensor according to the first embodiment is that a first magnetization region 51 and a second magnetization region 52 are formed in the shaft 5 of the magnetoelastic torque sensor 10 according to the second embodiment.

[0111] Furthermore, from Figure 8It can be seen that the first magnetized region 51 and the second magnetized region 52 have opposite magnetizations. The magnetizations of the first magnetized region 51 and the second magnetized region 52 can be chosen to be the same in value. However, it is also possible that the magnetizations of the magnetized regions 51 and 52 are different.

[0112] See again Figure 7 The first magnetic field sensor 1 and the second magnetic field sensor 2 are assigned to the first magnetization region 51, and the third magnetic field sensor 3 is assigned to the second magnetization region 52. That is, the first magnetic field sensor 1 and the second magnetic field sensor 2 are respectively configured to detect the magnetic flux density of the magnetic field (presented by magnetic flux lines 55) generated by the first magnetization region 51 when the shaft 5 is subjected to torque stress, and the third magnetic field sensor 3 is configured to detect the magnetic flux density of the magnetic field (presented by magnetic flux lines 56) generated by the second magnetization region 52 when the shaft 5 is subjected to torque stress.

[0113] Figure 9 A graph showing the magnetic flux density of the magnetic field in the axial direction 111 is shown. This magnetic field can be generated when the shaft 5 of the first exemplary magnetoelastic torque sensor 10 according to the second embodiment is subjected to a torque load and can be detected by the three magnetic field sensors 1, 2, and 3 of the torque sensor 10. Figure 10 A graph showing the magnetic flux density of the magnetic field in the axial direction 111 is shown. This magnetic field can be generated when the shaft 5 of the second exemplary magnetoelastic torque sensor 10 according to the second embodiment is subjected to a torque load and can be detected by the three magnetic field sensors 1, 2, and 3 of the torque sensor 10. Figure 11 A graph showing the magnetic flux density of the magnetic field in the axial direction 111 is shown. This magnetic field can be generated when the shaft 5 of the third exemplary magnetoelastic torque sensor 10 according to the second embodiment is subjected to a torque load and can be detected by the three magnetic field sensors 1, 2, and 3 of the torque sensor 10.

[0114] In each graph, the x-axis 207 represents the distance along axis 5 in the axial direction 111, measured from the origin 209, in mm, while the y-axis 208 represents the component of magnetic flux density in the axial direction 111, in μT. The zero value at the origin 209 in the x-axis 207 corresponds to the beginning of axis 5.

[0115] for Figure 9 The first exemplary magnetoelastic torque sensor 10 is applicable to: ,in, .

[0116] Magnetic field sensors 1, 2, and 3 are arranged relative to each other, relative to the first magnetization region 51, and relative to the second magnetization region 52, such that the two slopes 210 and 211 are both negative and of different magnitudes.

[0117] for Figure 10 The second exemplary magnetoelastic torque sensor 10 is applicable to: ,in, .

[0118] Here, magnetic field sensors 1, 2, and 3 are arranged relative to each other, relative to the first magnetization region 51, and relative to the second magnetization region 52, such that slopes 210 and 211 have different magnitudes, wherein the first slope 210 is zero and the second slope is negative.

[0119] from Figure 9 and Figure 10 A comparison between exemplary magnetoelastic torque sensors 10 yields results based on... Figure 10 The distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 in the magnetostrictive torque sensor 10 is greater than that in the distance according to Figure 9 This distance in the magnetoelastic torque sensor 10. On the other hand, the two magnetoelastic torque sensors 10 have the same distance between the corresponding second magnetic field sensor 2 and the corresponding third magnetic field sensor 3, such that, according to Figure 10 The ratio of distance 12 to distance 23 in the magnetoelastic torque sensor 10 is greater than that according to Figure 9 This ratio in the magnetoelastic torque sensor 10.

[0120] for Figure 11 An exemplary magnetoelastic torque sensor 10, applicable to: ,in, .

[0121] from Figure 10 and Figure 11 A comparison between exemplary magnetoelastic torque sensors 10 yields results based on... Figure 11 The distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 in the magnetostrictive torque sensor 10 is greater than that in the distance according to Figure 10 This distance is in the magnetoelastic torque sensor 10. Although according to Figure 11 The distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 in the magnetoelastic torque sensor 10 is also greater than that in the case of... Figure 10 This distance in the magnetostrictive torque sensor 10, but distances 12 and 23 are selected such that, according to Figure 11The ratio of distance 12 to distance 23 in the magnetoelastic torque sensor 10 is greater than that according to Figure 10 This ratio in the magnetoelastic torque sensor 10.

[0122] If now Figures 9 to 11 By comparing the magnetostrictive torque sensors 10 with each other, it can be determined that... Figure 9 The magnetostrictive torque sensor 10 is the most compact in the axial direction 111, wherein, Figure 11 The magnetostrictive torque sensor 10 has the lowest compactness in the axial direction 111. On the other hand, Figure 11 The magnetostrictive torque sensor 10 has the largest useful signal obtained after calculating a single signal with respect to the applied torque using formula (5b), where, Figure 9 The magnetostrictive torque sensor 10 has the lowest obtained useful signal after calculating a single signal relative to the applied torque using formula (5b).

[0123] In general, this means that, for example, at a given magnetization and a specified external sensor location, the maximization of the resulting effective useful signal is achieved after settling the single signal and relative to the applied torque of the magnetostrictive torque sensor 10 by freely choosing distances 12 and 23.

[0124] Figure 12 A magnetoelastic torque sensor 10 according to a third embodiment of the present invention is shown.

[0125] The difference between the magnetoelastic torque sensor 10 according to the third embodiment and the magnetoelastic torque sensor according to the first embodiment is that the magnetoelastic torque sensor 10 according to the third embodiment has a fourth magnetic field sensor 4 in addition to the first magnetic field sensor 1, the second magnetic field sensor 2 and the third magnetic field sensor 3.

[0126] Here, the third magnetic field sensor 3 is arranged in the axial direction 111 between the second magnetic field sensor 2 and the fourth magnetic field sensor 4, and has a distance 34 from the fourth magnetic field sensor 4 in the axial direction 111.

[0127] Furthermore, all four magnetic field sensors 1, 2, 3, and 4 are associated with the magnetization region 51. That is, the fourth magnetic field sensor 4, like the first magnetic field sensor 1, the second magnetic field sensor 2, and the third magnetic field sensor 3, has at least one measuring axis and is configured to detect the component of the magnetic flux density of the magnetic field in the direction of the at least one measuring axis, which is generated by the magnetization region 51 when the shaft 5 is subjected to a torque load.

[0128] In the magnetoelastic torque sensor 10 according to the third embodiment, the sum of the distance 12 in the axial direction 111 between the first magnetic field sensor 1 and the second magnetic field sensor 2, the distance 23 in the axial direction 111 between the second magnetic field sensor 2 and the third magnetic field sensor 3, and the distance 34 in the axial direction 1111 between the third magnetic field sensor 3 and the fourth magnetic field sensor 4 is greater than or equal to 6 mm and less than 20 mm.

[0129] The analysis and processing unit 6 is configured here to detect the fourth measurement signal from the fourth magnetic field sensor 4. For this purpose, the fourth magnetic field sensor 4 is connected to the analysis and processing unit 6, particularly in terms of information technology.

[0130] However, it is also possible that the interface between the magnetic field sensors 1, 2, 3, 4 and the analysis and processing unit 6 will be implemented in a similar manner.

[0131] In order to determine the torque applied to shaft 5, the analysis and processing unit 6 is configured to additionally use, in addition to the first measurement signal, the second measurement signal, the third measurement signal, and the ratio of the distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 in the axial direction 111 to the distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 in the axial direction 111, the fourth measurement signal and the ratio of the distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 in the axial direction 111 to the distance 34 between the third magnetic field sensor 3 and the fourth magnetic field sensor 4 in the axial direction 111, in addition to the first measurement signal, the second measurement signal, the third measurement signal, and the ratio of the distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 in the axial direction 111 to the distance 34 between the third magnetic field sensor 3 and the fourth magnetic field sensor 4.

[0132] In particular, the fourth measurement signal, like the first, second, and third measurement signals, is also an offset-cleared measurement signal. Offset clearing is performed advantageously in a state of no torque and no interference field.

[0133] Here, the first measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the first magnetic field sensor, the second measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the second magnetic field sensor, the third measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the third magnetic field sensor, and the fourth measurement signal corresponds to the component of the magnetic flux density of the magnetic field in the axial direction at the position of the fourth magnetic field sensor.

[0134] Preferably, the analysis and processing unit 6 is configured to determine the torque applied to the shaft 5 using the following formula: Where 0 ≤ k ≤ 1. Here: • M is the torque to be determined, expressed in "Nm". • BSE1 It is the component of the magnetic flux density in the axial direction at the location of the first magnetic field sensor, expressed in μT. • B SE2 It is the component of the magnetic flux density in the axial direction at the location of the second magnetic field sensor, expressed in μT. • B SE3 It is the component of the magnetic flux density along the axial direction at the location of the third magnetic field sensor, expressed in μT. • B SE4 It is the fourth measurement signal, measured in μT. • d 12 The distance 12 between the first magnetic field sensor 1 and the second magnetic field sensor 2 is measured in mm. • d 23 The distance 23 between the second magnetic field sensor 2 and the third magnetic field sensor 3 is measured in mm. • d 34 The distance 34 between the third magnetic field sensor 3 and the fourth magnetic field sensor 4 is measured in mm. • S 14 The sensitivity of the magnetoelastic torque sensor 10 is measured in Nm / μT, ​​and... • k is a weighting factor that optimizes the compensation characteristics (complete elimination) for the nonlinear interference field share specific to the application or, in general, minimizes the worst-case error caused by the nonlinear interference field share.

[0135] This calculation formula allows for the elimination of the interference field share caused by the uniform interference field and the superimposed linear interference field gradient when calculating torque, independent of the chosen value of the weighting factor k (as long as 0 ≤ k ≤ 1). Furthermore, the weighting factor can shield and eliminate the nonlinear share of the interference field gradient, or minimize worst-case errors when different nonlinear interference field gradients exist in the environment surrounding the shaft 5 or the magnetoelastic torque sensor 10, as is the case when used in applications with variable locations and environments, where the same nonlinear interference field gradient cannot always be guaranteed.

[0136] Advantageously, the sensitivity of the magnetoelastic torque sensor 10 is determined by means of two-point calibration in the absence of a disturbing field and after offset clearance. In particular, the sensitivity is determined according to Formula 7 from the general part of this specification.

[0137] In particular, the first magnetic field sensor 1, the second magnetic field sensor 2, the third magnetic field sensor 3, and the fourth magnetic field sensor 4 are arranged relative to each other and relative to the magnetized region 51 such that the following conditions are satisfied: Where 0≤k≤1.

[0138] Here: • N SE1 It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the first magnetic field sensor 1, which is in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • N SE2 It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the second magnetic field sensor 2, which is in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • N SE3 It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the third magnetic field sensor 3, in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • N SE4 It is a predetermined component of the magnetic flux density of the magnetic field generated by the magnetized region 51 at the location of the fourth magnetic field sensor 4, in μT, caused by the stress on the shaft 5 due to the maximum torque that can be measured by the magnetoelastic torque sensor 10. • d 12 The distance 12 between the first magnetic field sensor and the second magnetic field sensor 10 is measured in mm. • d 23 The distance 23 between the second magnetic field sensor and the third magnetic field sensor 10 is measured in mm. • d 34 The distance 34 between the third and fourth magnetic field sensors 10 is measured in mm. • k is the weighting factor described earlier.

[0139] In particular, the predetermined magnetic flux density mentioned above is a magnetic flux density that has been offset-cleared and is free of interference fields.

[0140] Figure 13 A magnetoelastic torque sensor 10 according to a fourth embodiment of the present invention is shown.

[0141] The difference between the magnetoelastic torque sensor 10 according to the fourth embodiment and the magnetoelastic torque sensor according to the third embodiment is that the magnetoelastic torque sensor 10 according to the fourth embodiment has a second magnetization region 52 in addition to the first magnetization region 51.

[0142] Here, the first magnetic field sensor 1 and the second magnetic field sensor 2 are assigned to the first magnetization region 51, while the third magnetic field sensor 3 and the fourth magnetic field sensor 4 are assigned to the second magnetization region 52.

[0143] That is, the first magnetic field sensor 1 and the second magnetic field sensor 2 are respectively configured to detect one or more (two or three) components of the magnetic flux density of the magnetic field generated by the first magnetization region 51 when the shaft 5 is subjected to a torque load, wherein the third magnetic field sensor 3 and the fourth magnetic field sensor 4 are respectively configured to detect one or more (two or three) components of the magnetic flux density of the magnetic field generated by the second magnetization region 52 when the shaft 5 is subjected to a torque load.

[0144] In particular, the first magnetized region 51 and the second magnetized region 52 have opposite, numerically identical, magnetizations. Alternatively, the magnetization values ​​of magnetized regions 51 and 52 are different.

[0145] Although the magnetoelastic torque sensor 10 according to the first embodiment has been described in conjunction with the source Figure 6 The vehicle 100, however, should be noted that the magnetoelastic torque sensor 100 according to one embodiment of the other described embodiments can also be used in the vehicle 100.

[0146] A particular advantage of the present invention is that even if the shaft 5 of the magnetostrictive torque sensor 10 has only (at most) one magnetization region 51 or only (at most) two magnetization regions 52, i.e. less than three magnetization regions, the described interference field elimination / compensation can still be achieved.

[0147] It should be noted that, however, the described interference field elimination / compensation can also be achieved using the present invention by means of an axis 5 having more than two magnetization regions.

[0148] In addition to the above written description of the invention, specific references are hereby made. Figures 1 to 13 The graphic representation of the present invention is provided for its supplementary disclosure.

Claims

1. A magnetostrictive torque sensor (10), comprising: - A shaft (5) having only a first magnetized region (51) and a second magnetized region (52), wherein the first magnetized region (51) and the second magnetized region (52) have opposite magnetizations. - Wherein, the shaft (5) has an axial direction (111) and a radial direction (112). - At least three magnetic field sensors, each having at least one measuring axis and configured to detect components of the magnetic flux density of the magnetic field in the direction of the at least one measuring axis, and - Analysis and processing unit (6). - Wherein, the at least three magnetic field sensors include a first magnetic field sensor (1), a second magnetic field sensor (2), and a third magnetic field sensor (3), wherein the second magnetic field sensor (2) is arranged in the axial direction (111) between the first magnetic field sensor (1) and the third magnetic field sensor (3). - Wherein, the first magnetic field sensor (1) and the second magnetic field sensor (2) are associated with the first magnetization region (51) and the third magnetic field sensor (3) is associated with the second magnetization region (52). - Wherein, at least one of the at least three magnetic field sensors is arranged relative to the at least one magnetized region (51; 52) such that the magnetic field sensor is configured to detect the component of the magnetic flux density of the magnetic field in the direction of the corresponding at least one measuring axis, wherein the magnetic field can be generated by the at least one magnetized region (51; 52) when the shaft (5) is subjected to torsional stress, and - The analysis and processing unit (6) is configured to: detect at least one measurement signal of the first magnetic field sensor (1), at least one measurement signal of the second magnetic field sensor (2) and at least one measurement signal of the third magnetic field sensor (3), and determine the torque applied to the shaft (5) based on the at least one measurement signal of the first magnetic field sensor (1), the at least one measurement signal of the second magnetic field sensor (2), the at least one measurement signal of the third magnetic field sensor (3), and the ratio of the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in the axial direction (111) to the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in the axial direction (111).

2. The magnetostrictive torque sensor (10) according to claim 1, wherein, The at least one measuring axis of the first magnetic field sensor (1) and / or the at least one measuring axis of the second magnetic field sensor (2) and / or the at least one measuring axis of the third magnetic field sensor (3) are respectively included as measuring axes parallel to the axial direction (111) or the radial direction (112) of the shaft (5), wherein the at least one measuring signal of the first magnetic field sensor (1) includes a first measuring signal, the first measuring signal corresponding to the magnetic flux density of the magnetic field at the position of the first magnetic field sensor (1) in the axial direction (111) or the radial direction (112) of the shaft (5). The degree component, and / or, the at least one measurement signal of the second magnetic field sensor (2) includes a second measurement signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the second magnetic field sensor (2) in the axial direction (111) or radial direction (112) of the shaft (5), and / or, the at least one measurement signal of the third magnetic field sensor (3) includes a third measurement signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the third magnetic field sensor (3) in the axial direction (111) or radial direction (112) of the shaft (5), or Wherein, the at least one measuring axis of the first magnetic field sensor (1) and / or the at least one measuring axis of the second magnetic field sensor (2) and / or the at least one measuring axis of the third magnetic field sensor (3) respectively include two or three measuring axes orthogonally oriented relative to each other, wherein the at least one measuring signal of the first magnetic field sensor (1) includes two or three measuring signals, and / or, the at least one measuring signal of the second magnetic field sensor (2) includes two or three measuring signals, and / or, the at least one measuring signal of the third magnetic field sensor (3) includes two or three measuring signals, wherein the component of the magnetic flux density of the magnetic field at the corresponding position of the magnetic field sensor in the axial direction (111) or radial direction (112) of the shaft (5) can be determined by the two or three measuring signals of the respective magnetic field sensor.

3. The magnetostrictive torque sensor (10) according to claim 1, wherein, The analysis and processing unit (6) is configured to additionally use the sensitivity of the magnetoelastic torque sensor (10) in order to determine the torque applied to the shaft (5).

4. The magnetostrictive torque sensor (10) according to claim 3, wherein, The analysis and processing unit is configured to determine the torque applied to the shaft (5) using the following formula: ， in: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density of the magnetic field at the location of the first magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE2 It is the component of the magnetic flux density of the magnetic field at the location of the second magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE3 It is the component of the magnetic flux density of the magnetic field at the position of the third magnetic field sensor in the axial direction or radial direction, expressed in "μT". • d 12 It is the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in mm. • d 23 It is the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in mm, and • s 13 The sensitivity of the magnetoelastic torque sensor (10) is expressed in "Nm / μT".

5. The magnetostrictive torque sensor (10) according to claim 3, wherein, The analysis and processing unit (6) is configured to determine the torque applied to the shaft (5) using the following formula: ， Where 0≤k≤l, in: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density of the magnetic field at the location of the first magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE2 It is the component of the magnetic flux density of the magnetic field at the location of the second magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE3 It is the component of the magnetic flux density of the magnetic field at the position of the third magnetic field sensor in the axial direction or radial direction, expressed in "μT". • d 12 It is the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in mm. • d 23 It is the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in mm. • s 13 The sensitivity of the magnetoelastic torque sensor (10) is expressed in Nm / μT, ​​and • k is the weighting factor.

6. The magnetostrictive torque sensor (10) according to claim 5, wherein, 0.9≤k<l or l<k≤1.

1.

7. The magnetostrictive torque sensor (10) according to any one of claims 1 to 6, wherein, The first magnetic field sensor (1), the second magnetic field sensor (2), and the third magnetic field sensor (3) are arranged relative to each other and relative only to the first magnetization region (51) and the second magnetization region (52) such that one of the following two conditions is satisfied: ,in, ,in, , in: • N SE1 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the first magnetic field sensor (1) due to the stress on the shaft (5) caused by the maximum torque that can be measured by the magnetoelastic torque sensor (10). • N SE2 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the second magnetic field sensor (2), in "μT", caused by the stress on the shaft (5) due to the maximum torque that can be measured by the magnetoelastic torque sensor (10). • N SE3 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the third magnetic field sensor (3) due to the stress on the shaft (5) caused by the maximum torque that can be measured by the magnetoelastic torque sensor (10). • d 12 It is the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in mm, and • d 23 It is the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in mm.

8. The magnetostrictive torque sensor (10) according to claim 7, wherein, The first magnetic field sensor (1), the second magnetic field sensor (2), and the third magnetic field sensor (3) are arranged relative to each other and relative only to the first magnetization region (51) and the second magnetization region (52) such that one of the following two conditions is satisfied: ,in, , ,in, .

9. The magnetostrictive torque sensor (10) according to any one of claims 1 to 6, wherein, The sum of the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in the axial direction (111) and the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in the axial direction (111) is greater than or equal to 4 mm and less than 20 mm.

10. The magnetostrictive torque sensor (10) according to any one of claims 1 to 3, wherein, The at least three magnetic field sensors include a first magnetic field sensor (1), a second magnetic field sensor (2), a third magnetic field sensor (3), and a fourth magnetic field sensor (4), wherein the third magnetic field sensor (3) is arranged in the axial direction (111) between the second magnetic field sensor (2) and the fourth magnetic field sensor (4), wherein the analysis and processing unit (6) is configured to: detect at least one measurement signal of the fourth magnetic field sensor (4), and additionally use the at least one measurement signal of the fourth magnetic field sensor (4) to determine the torque applied to the shaft (5), and the ratio of the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in the axial direction (111) to the distance (34) between the third magnetic field sensor (3) and the fourth magnetic field sensor (4) in the axial direction (111).

11. The magnetoelastic torque sensor (10) according to claim 10, wherein, The at least one measuring axis of the fourth magnetic field sensor (4) includes a measuring axis parallel to the axial direction (111) or radial direction (112) of the shaft, wherein the at least one measuring signal of the fourth magnetic field sensor (4) includes a fourth measuring signal corresponding to the component of the magnetic flux density of the magnetic field at the position of the fourth magnetic field sensor (4) in the axial direction (111) or radial direction (112) of the shaft (5), or wherein the at least one measuring axis of the fourth magnetic field sensor (4) includes two or three measuring axes orthogonally oriented relative to each other, wherein the at least one measuring axis of the fourth magnetic field sensor (4) includes two or three measuring signals, the two or three measuring signals being able to determine the component of the magnetic flux density of the magnetic field at the position of the fourth magnetic field sensor (4) in the axial direction (111) or radial direction (112) of the shaft (5).

12. The magnetoelastic torque sensor (10) according to claim 10, wherein, The analysis and processing unit (6) is configured to determine the torque applied to the shaft (5) using the following formula: Where 0≤k≤l, where: • M is the torque to be determined, expressed in "Nm". • B SE1 It is the component of the magnetic flux density of the magnetic field at the location of the first magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE2 It is the component of the magnetic flux density of the magnetic field at the location of the second magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE3 It is the component of the magnetic flux density of the magnetic field at the position of the third magnetic field sensor in the axial direction or radial direction, expressed in "μT". • B SE4 It is the component of the magnetic flux density at the position of the fourth magnetic field sensor in the axial direction or radial direction, expressed in "μT". • d 12 It is the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in mm. • d 23 It is the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in mm. • d 34 It is the distance (34) between the third magnetic field sensor (3) and the fourth magnetic field sensor (4) in mm, and • s 14 The sensitivity of the magnetoelastic torque sensor (10) is expressed in Nm / μT, ​​and • k is the weighting factor.

13. The magnetostrictive torque sensor (10) according to claim 10, wherein, The first magnetic field sensor (1), the second magnetic field sensor (2), the third magnetic field sensor (3), and the fourth magnetic field sensor (4) are arranged relative to each other and relative only to the first magnetization region (51) and the second magnetization region (52) such that the following condition is satisfied: Where 0≤k≤l, in: • N SE1 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the first magnetic field sensor (1), which is caused by the stress on the shaft (5) due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE2 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the second magnetic field sensor (2), which is caused by the stress on the shaft (5) due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE3 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the third magnetic field sensor (3), which is caused by the stress on the shaft (5) due to the maximum torque that can be measured by the magnetoelastic torque sensor. • N SE4 It is a predetermined component of the magnetic flux density of the magnetic field generated by the at least one magnetized region (51; 52) at the location of the fourth magnetic field sensor (4), which is caused by the stress on the shaft (5) due to the maximum torque that can be measured by the magnetoelastic torque sensor (10). • d 12 It is the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in mm. • d 23 It is the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in mm. • d 34 It is the distance (34) between the third magnetic field sensor (3) and the fourth magnetic field sensor (4) in mm.

14. The magnetoelastic torque sensor (10) according to claim 13, wherein, The first magnetic field sensor (1), the second magnetic field sensor (2), the third magnetic field sensor (3), and the fourth magnetic field sensor (4) are arranged relative to each other and relative only to the first magnetization region (51) and the second magnetization region (52) such that the following condition is satisfied: Where 0 ≤ k ≤ l.

15. The magnetoelastic torque sensor (10) according to claim 12, wherein, The sum of the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in the axial direction (111), the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in the axial direction (111), and the distance between the third magnetic field sensor (3) and the fourth magnetic field sensor (4) is greater than or equal to 6 mm and less than 20 mm.

16. The magnetostrictive torque sensor (10) according to claim 10, wherein, The first magnetic field sensor (1) and the second magnetic field sensor (2) are associated with the first magnetization region (51), and the third magnetic field sensor (3) and the fourth magnetic field sensor (4) are associated with the second magnetization region (52).

17. The magnetostrictive torque sensor (10) according to any one of claims 1 to 6, wherein, The magnetoelastic torque sensor (10) is configured to compensate for the uniform disturbance field and linear disturbance field gradient in the axial direction (111) of the shaft (5).

18. The magnetostrictive torque sensor (10) according to any one of claims 1 to 6, wherein, The first magnetized region (51) and the second magnetized region (52) have different magnetization values.

19. A vehicle (100) comprising a magnetostrictive torque sensor (10) according to any one of claims 1 to 18, wherein, The magnetoelastic torque sensor (10) is arranged on the crank drive mechanism (102).

20. The vehicle according to claim 19, wherein, The vehicle (100) is operable by electricity and / or by human power and has a crank transmission mechanism (102).

21. A method for determining torque when using a magnetostrictive torque sensor (10) according to any one of claims 1 to 18, wherein, The method includes the following steps: - Detect at least one measurement signal from the first magnetic field sensor (1), which includes a first measurement signal, - Detect at least one measurement signal from the second magnetic field sensor (2), which includes the second measurement signal, - Detect at least one measurement signal from the third magnetic field sensor (3), which includes a third measurement signal, and The torque applied to the shaft (5) is determined based on the first measurement signal, the second measurement signal, the third measurement signal, and the ratio of the distance (23) between the second magnetic field sensor (2) and the third magnetic field sensor (3) in the axial direction (111) to the distance (12) between the first magnetic field sensor (1) and the second magnetic field sensor (2) in the axial direction (111).

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