DE102017222574A1 - Sensor system for determining at least one rotational property of a rotating element - Google Patents

Abstract

A sensor system (110) for determining at least one rotational property of an element (112) rotating about at least one axis of rotation A is proposed. The sensor system (110) comprises: - at least one first sender wheel (112), wherein the first sender wheel (112) is connectable to at least a first part (116) of a rotating element (112), wherein the first sender wheel (112) at least two first electrically conductive segments (148) and at least two first electrically non-conductive segments (150), which are each arranged radially about the axis of rotation A, - at least one second encoder wheel (124), wherein the second encoder wheel (124) with at least a second part (118) of the rotating element (112) is connectable, - at least one torsion element (120), wherein the first part (116) and the second part (118) are rotatably coupled to each other by the torsion element (120), - at least one sensor element ( 134), wherein the sensor element (134) is arranged, a relative rotation of the first encoder wheel (112) and the second encoder wheel (124) to each other depending on a Überdeckungsmaß the first electrically conductive Segmen te (148) and the second electrically conductive segments (138) to determine; characterized in that the second encoder wheel comprises at least two second electrically non-conductive segments (140) and at least two second electrically conductive segments (138), each disposed radially about the axis of rotation A, the second electrically conductive segments (138) each at least one electrically conductive sub-segment (160) and at least electrically non-conductive sub-segment (162).

Description

State of the art

Numerous sensors are known from the prior art which detect at least one rotational property of rotating elements. Examples of such sensors are described in Konrad Reif (ed.): Sensors in motor vehicles, 2nd edition, 2012, pages 63-74 and 120-129. For example, a position of a camshaft of an internal combustion engine can be determined relative to a crankshaft with a so-called phase encoder by means of a Hall sensor.

Typically, a donor wheel is mounted on the rotating axle. There may be teeth on the sender wheel that are sensed by the Hall sensor as the camshaft rotates. So will in the DE 10 2012 213 539 A1 a method for determining a phase angle of an adjustable camshaft of an internal combustion engine, which comprises a transmitter wheel and a camshaft adjuster is described. The phase angle of the camshaft is determined on the basis of triggered by the encoder wheel phase edge interrupts and a model that is dependent on at least one operating characteristic of the camshaft adjuster.

In DE 10 2004 019 379 A1 For example, a method and apparatus for determining a differential angle will be described. Torque in a powertrain should be easier and better recorded. For this purpose, it is provided to determine a differential angle at two measuring points by subtracting the rotational angles at the two measuring points in each case applied with a corresponding transmission ratio. From the differential angle can be closed directly to a transmitted torque without detouring over the rotational speed.

Despite the improvements made by such sensor devices, there is still room for improvement. A challenge in many known methods is still to allow a simultaneous determination of a rotation angle of a shaft and a torque.

Disclosure of the invention

In the context of the present invention, therefore, a sensor system for determining at least one rotational property of a rotating element is proposed.

The sensor system comprises at least a first sender wheel. The first encoder wheel is connectable to at least a first part of a rotating element. The first encoder wheel comprises at least two first electrically conductive segments and at least two first electrically non-conductive segments, which are each arranged radially around the axis of rotation. The sensor system comprises at least one second sender wheel. The second encoder wheel is connectable to at least a second part of the rotating element. The second encoder wheel comprises at least two second electrically non-conductive segments, which are each arranged radially around the axis of rotation. The sensor system further comprises at least one torsion element, wherein the first part and the second part are rotatably coupled to each other by the torsion element and at least one sensor element. The second encoder wheel further comprises at least two electrically conductive segments, which are each arranged radially around the axis of rotation. The electrically conductive segments each have at least one electrically conductive sub-segment and at least electrically non-conductive sub-segment. The electrically non-conductive sub-segment can be within a radius r ₁ be arranged about the axis of rotation and the electrically conductive sub-segment may be disposed within a radius r ₂ about the axis of rotation, wherein r ₁ <r ₂ .

In the context of the present invention, a "sensor system" is basically understood to mean any device which is suitable for detecting at least one measured variable. Accordingly, a sensor system for determining at least one rotation property is understood to mean a sensor system which is set up to detect, for example measure, the at least one rotation property and which can generate, for example, at least one electrical signal corresponding to the detected property, such as a voltage or a Electricity. Combinations of properties can also be detected.

In the context of the present invention, a "rotation property" is basically understood to mean a property which at least partially describes the rotation of the rotating element. This may, for example, be an angular velocity, a rotational speed, an angular acceleration, an angular position or another property which may at least partially characterize a continuous or discontinuous, uniform or non-uniform rotation or rotation of the rotating element. For example, the rotation property may be a position, in particular an angular position, an angular acceleration or a combination of at least two of these variables. Other properties and / or other combinations of properties may also be detectable.

In particular, the rotation property may be a rotation angle. The term "rotation" generally refers to a self-imaging of an object with at least one fixed point. When rotated, distances, lengths and angles of the object can remain unchanged, only one layer can change. During rotation, a point may be fixed that does not change its position. The point can be called a fixed point or center of rotation. During the rotation, in principle all points of the object are shifted by an identical angle of rotation, which can be designated as an angle between P and P '. The object basically only changes its position during rotation, its appearance remains the same. This is because the distance of the points P and P 'to the center of rotation Z remains identical. In the context of the present invention, a "rotation angle" is basically understood to mean an angle about which a geometric object is rotated. The angle of rotation is thus the same for all points of the object. Furthermore, the rotation property may be a torque. The term "torque" generally refers to a rotational action of a force on any rotatably mounted object. The torque basically indicates how strong a force acts on the rotatably mounted object. Decisive for an effect of a force on a rotatable body may be an amount of force, a direction of the force and a distance of a line of action of the force from the axis of rotation. In particular, the sensor system can be configured to determine at least one angle of rotation and at least one torque.

In the context of the present invention, a "rotating element" is basically understood to mean any element which rotates about at least one axis. For example, the rotating element may be a shaft, for example a shaft in an engine, for example a camshaft or a crankshaft. For example, an angular position of a camshaft or a rotational speed of a camshaft or an angular acceleration of a camshaft or a combination of at least two of these variables can be determined. Other properties and / or other combinations of properties may also be detectable.

The rotating element may have a first part and a second part. The terms "first part" and "second part" are to be considered as pure descriptions without indicating an order or ranking and, for example, without precluding the possibility that several types of first parts or second parts or exactly one kind may be provided. Furthermore, additional parts, for example, one or more third parts may be present.

The term "torsion element" basically refers to any element which, in the case of a load with a torque and / or a torsional moment, which acts around a longitudinal axis of the element, is deformable, in particular helically deformable. An effect of the torsion moment on the element can cause an object to twist through a twist angle and distort it by a shear angle. The torsion element can in particular be wholly or partly designed as a cylinder, in particular as a hollow cylinder. The first encoder wheel and the second encoder wheel can be rotated by a torsion angle against each other. The torsion angle can therefore correspond to a difference angle between the first encoder wheel and the second encoder wheel. The torsion angle may in particular be 0.25 to 10 °, preferably 0.5 to 5 ° and particularly preferably 1 to 3 °.

The terms "first sender wheel" and "second sender wheel" are to be regarded as pure descriptions without indicating an order or ranking and excluding, for example, without the possibility that several types of first donor wheels or second donor wheels or just one kind may be provided. Furthermore, additional donor wheels, for example, one or more third donor wheels may be present. In the context of the present invention, a "sensor wheel" can in principle be understood to be any component which can be connected to the rotating element and is designed to effect at least one measurable signal, in particular a change in magnetic field, upon connection to the rotating element per revolution of the rotating element.

As already mentioned above, the first sender wheel can be connected to the first part of the rotating element and the second sender wheel can be connected to the second part of the rotating element. First sender wheel and / or the second sender wheel, for example, permanently or reversibly connected to the rotating element or connectable or can also be integrally formed with the rotating element or integrated into the rotating element.

The second sender wheel may have a connecting element, for example a sleeve, wherein the connecting element is set up to connect the second sender wheel firmly to the second part of the rotating element and / or to the torsion element. The connecting element may in particular have a recess and the second part of the rotating element may be at least partially received in the recess. The second encoder wheel may be formed at least partially planar and the connecting element may be at least partially formed as a hollow cylinder. The torsion element may be at least partially enveloped by the connecting element.

The first sender wheel and the second sender wheel can be arranged in particular at a distance of 100 .mu.m to 1000 .mu.m, in particular from 200 .mu.m to 800 .mu.m and particularly preferably from 50 .mu.m to 150 .mu.m to each other. However, the first sender wheel and the second sender wheel can also be arranged such that the first sender wheel and the second sender wheel touch.

The first sender wheel and / or the second sender wheel may in particular be configured in a planar manner. Furthermore, the first sender wheel and / or the second sender wheel may have an at least partially circular basic shape.

The terms "first electrically conductive segment", "first electrically non-conductive segment", "second electrically conductive segment" and "second electrically non-conductive segment" are to be regarded as mere descriptions without indicating an order or ranking and without precluding, for example, that a plurality of types of first electrically conductive segments or second electrically conductive segments or in each case exactly one type can be provided. Furthermore, additional segments, for example one or more third electrically conductive segments may be present.

The first electrically conductive segments, the second electrically conductive segments, the first electrically non-conductive segments and / or the second electrically non-conductive segments may each be formed at least partially planar. The first electrically conductive segments, the second electrically conductive segments, the first electrically non-conductive segments and / or the second electrically non-conductive segments may continue to extend transversely, in particular perpendicular to the axis of rotation. In particular, the first electrically conductive segments, the second electrically conductive segments, the first electrically nonconductive segments and / or the second electrically nonconductive segments may be circular sector segments. The term "circular sector" basically denotes any partial area of a circular area which is delimited by at least one circular arc and at least two circular radii. Other forms are conceivable in principle. For example, the segments may be at least partially formed as a pin-shaped, a tooth-shaped or a serrated bulge or recess.

The first encoder wheel may have at least three of the first electrically conductive segments and at least three of the first electrically non-conductive segments, in particular three of the first electrically conductive segments and three of the first electrically non-conductive segments. The second encoder wheel may have at least three of the second electrically conductive segments and at least three of the second electrically non-conductive segments, in particular three of the second electrically conductive segments and three of the second electrically non-conductive segments. In particular, a number of the first electrically non-conductive segments may be identical to a number of the first electrically conductive segments. In particular, a number of the second electrically non-conductive segments may be identical to a number of the segments.

The first electrically non-conductive segments and / or the second electrically non-conductive segments and / or the electrically conductive sub-segments may each be wholly or at least partially made of at least one electrically non-conductive material. The non-conductive material may in particular have an electrical conductivity of less than 10 ^-8 S · cm ^-1 and a resistivity of greater than 10 ⁸ Ω · cm. Furthermore, the first electrically non-conductive segments and / or the second electrically non-conductive segments and / or the electrically conductive sub-segments may be wholly or partly made of a material having poor electrical conductivity. The electrically poorly conductive material may in particular have an electrical conductivity of less than 10 ^-3 S · cm ^-1 . The first electrically non-conductive segments and / or the second electrically non-conductive segments and / or the electrically conductive sub-segments may in particular wholly or at least partially of at least one ceramic material and / or at least one flame retardant and flame retardant composite material, which at least epoxy resin and at least a glass fiber fabric. Furthermore, the first electrically non-conductive segments and / or the second electrically non-conductive segments may be formed as a circular sector-shaped recess. Other materials are also conceivable.

The first electrically conductive segments and / or the electrically conductive sub-segments may each be wholly or at least partially made of at least one material having an electrical conductivity greater than 10 ⁶ S · cm ^-1 . In particular, the first electrically conductive segments and / or the electrically conductive sub-segments may be wholly or at least partially made of at least one material selected from the group consisting of: aluminum, copper, steel. Other materials are also conceivable.

The first electrically conductive segments and the first electrically non-conductive segments may each have the same shape. The second electrically conductive segments and the second electrically non-conductive segments may each have the same shape.

The first electrically non-conductive segments may be at an angle α ₁ be spaced apart. The first electrically conductive segments can be at an angle β ₁ be spaced apart. The second electrically non-conductive segments may be at an angle α ₂ be spaced apart. The second electrically conductive segments may be at an angle β ₂ be spaced apart. The angle α ₁ and the angle α ₂ can be essentially the same size. The angle β ₁ and the angle β ₂ can be essentially the same size. Even slight deviations are tolerated. For example, deviations may be tolerated which are not more than 10%, in particular not more than 5% or even not more than 2% of the absolute value of the angle.

In particular, the first electrically conductive segments can each have a first circular-arc-shaped side, and the first electrically non-conductive segments can each have a second circular-arc-shaped side. The first circular arc-shaped side can be the angle α ₁ span to the axis of rotation and the second arcuate side can the angle β ₁ span to the axis of rotation. In particular, the second electrically conductive segments can each have a third circular-arc-shaped side, and the second electrically non-conductive segments can each have a fourth circular-arc-shaped side. The third circular arc-shaped side can be the angle α ₂ span to the axis of rotation and the fourth circular arc-shaped side can angle β ₂ span to the axis of rotation. The angle α ₁ and the angle α ₂ can be essentially the same size. The angle β ₁ and the angle α ₁ can be essentially the same size. The angle β ₂ and the angle α ₂ can be essentially the same size. The term "spaced apart at an angle" in the context of the present invention basically means that two or more objects, which extend radially from one axis, span the angle to the axis.

The first donor wheel can have a diameter d ₁ and the second encoder wheel may have a diameter d ₂ respectively. The diameter d _{2 of} the second sender wheel may preferably be 10 mm to 100 mm, preferably 20 mm to 80 mm and particularly preferably 30 mm to 50 mm. The ratio of d ₁ to d ₂ may in particular be 1: 2, preferably 1: 1.5. The first sender wheel may be arranged between the second sender wheel and the sensor element.

In the context of the present invention, the term "partial segment" is to be understood in principle to mean any part or any component of a segment, the segment having other components in addition to the partial segment, for example further partial segments. The electrically conductive sub-segment and the electrically non-conductive sub-segment can basically have any desired shape. In particular, the electrically conductive sub-segment and the electrically non-conductive sub-segment may be planar. Furthermore, the electrically conductive sub-segment and the electrically non-conductive sub-segment may be at least partially formed as circular sector segments. The electrically non-conductive sub-segment can be arranged between the axis of rotation and the electrically conductive sub-segment. The electrically conductive sub-segment may in particular be delimited by at least one outer circular-arc-shaped side and by at least one inner circular-arc-shaped side. The inner circular-arc-shaped side may face the electrically non-conductive partial segment. The outer circular arc-shaped side can be arranged at a distance from the axis of rotation which corresponds to the radius r ₂ equivalent. The inner circular arc-shaped side can be arranged at a distance to the axis of rotation which corresponds to the radius r ₁ equivalent. The inner circular arc-shaped side can adjoin the electrically non-conductive sub-segment.

The electrically non-conductive sub-segment may be attached to an annular member. The annular element may be arranged for fixing the second encoder wheel to the rotating element. The electrically non-conductive sub-segment may in particular be delimited by at least one further outer circular-arc-shaped side and by at least one inner circular-arc-shaped side. The further inner circular arc-shaped side may adjoin the annular element. The further outer circular arc-shaped side can adjoin the electrically non-conductive sub-segment.

The first sender wheel may have a further annular element which is arranged to fasten the first sender wheel to the rotating element. The first electrically conductive segment may be within a radius r ₃ be arranged around the axis of rotation. The radius r ₁ and the radius r ₃ can be essentially the same size. Furthermore, the radius r ₃ smaller than the radius r ₂ his. Furthermore, the radius r ₃ and the radius r ₂ be the same size.

Under a "sensor element" in the context of the present invention is basically a to understand any device which is adapted to detect at least one property or a measured variable, in particular a physical measured variable. The sensor element may in particular be designed to generate at least one sensor signal, in particular at least one electrical sensor signal, for example an analog and / or digital sensor signal. In particular, the detected property may include a position, for example an angular position. In particular, the sensor element may be an inductive magnetic sensor. However, other embodiments are possible in principle. The sensor element can be configured in particular as a printed circuit board. The sensor element may have a passage, and the rotating element, in particular the second part of the rotating element, may be accommodated at least partially in the passage. The sensor element may be arranged below the second encoder wheel. Furthermore, the sensor element may be fixed in relation to a rotation of the rotating element.

The sensor element may comprise at least one coil arrangement. In the context of the present invention, a "coil arrangement" can in principle be understood to mean any device which comprises at least one coil. In the context of the present invention, a "coil" is fundamentally understood to mean any component which has an inductance and is suitable for generating a magnetic field during current flow and / or vice versa. For example, a coil may comprise at least one complete or partially closed conductor loop or winding.

The sensor element may have at least one exciter coil. In the context of the present invention, an "exciter coil" can basically be understood to mean a coil which generates a magnetic flux when an electrical voltage and / or an electrical current are applied. The exciter coil may have at least one exciter coil. The exciter coil can therefore also be referred to as a circulating exciter coil. The excitation coil may be configured to be charged with an AC voltage. The alternating voltage can be 1 MHz to 10 MHz, preferably 2 MHz to 5 MHz and particularly preferably 3.5 MHz. The exciter coil may thus be arranged to generate an electromagnetic alternating field. The alternating electromagnetic field may be configured to couple in the receiver coils and induce interactions.

The sensor element may have a passage and the rotating element may be at least partially received in the bushing. The sensor element may be arranged below the first encoder wheel. Furthermore, the sensor element may be fixed in relation to a rotation of the rotating element.

The sensor element may comprise at least one coil arrangement. In the context of the present invention, a "coil arrangement" can in principle be understood to mean any device which comprises at least one coil. In the context of the present invention, a "coil" is fundamentally understood to mean any component which has an inductance and is suitable for generating a magnetic field during current flow and / or vice versa. For example, a coil may comprise at least one complete or partially closed conductor loop or winding.

The sensor element may have at least one exciter coil. In the context of the present invention, an "exciter coil" can basically be understood to mean a coil which generates a magnetic flux when an electrical voltage and / or an electrical current are applied. The exciter coil may have at least one exciter coil. The exciter coil can therefore also be referred to as a circulating exciter coil. In particular, the sensor element can have at least one first receiver coil and at least two second receiver coils or at least two of the first receiver coils and at least one of the second receiver coils.

The excitation coil may be configured to be charged with an AC voltage. The alternating voltage can be 1 MHz to 10 MHz, preferably 2 MHz to 5 MHz and particularly preferably 3.5 MHz. The exciter coil may thus be arranged to generate an electromagnetic alternating field. The alternating electromagnetic field may be configured to couple in the receiver coils and induce interactions.

The first receiver coils and the second receiver coils may be constructed of interconnects electrically connected to each other so that each of the first receiver coils and the second receiver coils is constructed of counter-current-oriented partial convolutions, each in a radial direction of at least one arcuate conductor track curved to the left and at least one opposite curved to the right arcuate conductor track is limited. The circular conductor tracks of the receiver coils can each have a same radius of curvature

The receiver coils may be formed at least partially circular segment. By way of example, a course of a complete circle may be included or only part of a circle. By "at least partially circular segment-shaped" can be understood in particular that the receiver coil has at least one portion which is shaped like a circle segment. In addition, one or more sections may be included, which do not have a circular segment-shaped course, for example, straight sections. In general, slight deviations from the circular shape are possible with a circular segment-shaped course. For example, deviations can be tolerated, which are at any point not more than 20%, in particular not more than 10% or even not more than 5% of the absolute value of the circular shape.

The receiver coil may in particular have several partial turns. In particular, the receiver coil may have a plurality of partial turns, which are formed as circular segments. The partial turns can be connected to one another, for example by one or more plated-through holes. The partial turns can be arranged in particular on several levels. In particular, the partial turns of a receiver coil can be oriented in opposite directions so that the partial turns intersect at least one point. In particular, the intersecting partial turns can run over one another, so that the two intersecting partial turns do not touch each other at the point of intersection.

The sensor system may be configured to detect an inductive coupling and / or a change in an inductive coupling between the exciter coil and the receiver coil. In particular, the sensor system can be set up, the inductive coupling caused by a movement and / or a position of the first sender wheel and the second sender wheel and / or the change in the inductive coupling between the exciter coil and the one caused by a movement and / or a position of the sender wheel To detect receiver coils. For this purpose, the sensor system may for example have a corresponding evaluation unit. In particular, the evaluation unit can have at least one evaluation circuit. In particular, the evaluation circuit may be configured to evaluate the signals of the position sensor. The evaluation circuit may be, for example, a processor. The evaluation unit can be arranged with the at least one coil arrangement on a common circuit carrier. The evaluation unit can also be arranged separately from the at least one coil arrangement.

A typical value range of a coupling factor may be, for example, -0.3 to +0.3. In this case, a coupling factor can be understood in particular to be an amplitude ratio between a received signal and a transmitted or exciter signal. The coupling factor can in particular run sinusoidally with the angle of rotation.

The receiver coils may be disposed within the exciter coil on a circuit board. The first receiver coils may be arranged in a first ring sector region. The first ring sector region may be defined by a first inner circle radius r _i1 around the axis of rotation and through a first outer circle radius r _a1 be defined around the axis of rotation. The second receiver coils may be arranged in a second ring sector region. The second ring sector region may be defined by a second inner circle radius r _i2 around the axis of rotation and through a second outer circle radius r _a2 be defined. It can hold: r _i1 <r _a1 <r _i2 <r _a2 .

In a further aspect of the present invention, a method is proposed for determining at least one rotational property of an element rotating about at least one axis of rotation. The method includes the use of at least one sensor system. The method according to the invention can comprise the method steps which are described below. The method steps may preferably be carried out in the predetermined order. In this case, one or even several method steps can be performed simultaneously or overlapping in time. Furthermore, one, several or all of the method steps can be carried out simply or repeatedly. The method may additionally comprise further method steps.

1. a) Aufnehmen induktiver Signale mittels des Sensorelements; und
2. b) Auswerten der induktiven Signale und Ermitteln der Rotationseigenschaft mittels der induktiven Signale.

The process steps are:

1. a) receiving inductive signals by means of the sensor element; and
2. b) evaluating the inductive signals and determining the rotation property by means of the inductive signals.

The method is carried out using a sensor system according to the present invention, ie according to one of the above-mentioned embodiments or according to one of the embodiments described in more detail below. Accordingly, for definitions and optional configurations, reference may be made largely to the description of the sensor system. However, other embodiments are possible in principle.

In particular, the inductive signals may be voltage signals, in particular in the Receiver coils generated voltages. In particular, the voltages in the receiver coils can be generated due to the inductive coupling of the receiver coils with the at least one exciter coil. In particular, the inductive coupling and / or the change in the inductive coupling in the coil arrangement may depend on a movement and / or on a position of the first encoder wheel and / or the second encoder wheel. Furthermore, the method may include determining the angular position of the rotating element and the torque using the detected, dependent on the position and / or the movement of the encoder wheels inductive coupling and / or changing the inductive coupling.

Furthermore, the method may include the processing of the inductive signals by an evaluation circuit. Furthermore, the method may include forwarding the inductive signals to a control device, for example a processor. Furthermore, the method may comprise a determination of the rotational property, for example the angular position, by means of an evaluation of the inductive signals.

Advantages of the invention

The proposed device and method have numerous advantages over known devices and methods. In particular, the device can be inexpensive, since only one sensor element is necessary. Furthermore, a sensor evaluation can basically be very simple, since a calculation effort is reduced. The sensor system can have a small installation space. Furthermore, the method can represent a simple measuring principle and have an easily implementable redundancy principle. Furthermore, the sensor system can have a very high sensitivity and the measuring principle can be independent of many external influences such as humidity, lubricants and interference fields. A sensor ASIC can basically be used here. Basically, the sensor system can be an externally robust system which, in contrast to magnetic principles, can also be used in an environment of high currents, in particular motor currents, for example in an electric vehicle. Signals and measured variables can be made plausible among one another, therefore an ASIL classification can be higher. A torque measurement can basically cause little additional costs.

list of figures

Further optional details and features of the invention will become apparent from the following description of preferred embodiments, which are shown schematically in the figures.

• 1 eine schematische Darstellung eines Ausführungsbeispiels eines erfindungsgemäßen Sensorsystems in einer Schnittdarstellung;
• 2A und 2B schematische Darstellungen von Ausführungsbeispielen eines ersten Geberrads (2A) und eines zweiten Geberrads (2B);
• 3A und 3B schematische Darstellung einer Basisstruktur eines Sensorelements (3A) und eines exemplarischen Ausführungsbeispiels eines Sensorelements (3B);
• 4A bis 4B drehmomentabhängige demodulierte Signale der Empfängerspulen für verschiedene Drehmomente; und
• 5A bis 5C verschiedene Ansichten des ersten Geberrads und des zweiten Geberrads in Draufsicht.

Show it:

• 1 a schematic representation of an embodiment of a sensor system according to the invention in a sectional view;
• 2A and 2 B schematic representations of embodiments of a first encoder wheel ( 2A) and a second donor wheel ( 2 B) ;
• 3A and 3B schematic representation of a basic structure of a sensor element ( 3A) and an exemplary embodiment of a sensor element ( 3B) ;
• 4A to 4B torque-dependent demodulated signals of the receiver coils for different torques; and
• 5A to 5C different views of the first encoder wheel and the second encoder wheel in plan view.

Embodiments of the invention

In 1 is an embodiment of a sensor system 110 shown. The sensor system 110 comprises a rotating element 112 , In particular, it may be in the rotating element 112 around a wave 114 act. The rotating element has a first part 116 and a second part 118 on. The first part 116 and the second part 118 are through a torsion element 120 connected with each other. The sensor system 110 also has at least one first sender wheel 122 and at least one second sender wheel 124 on. The first donor wheel 122 can with the first part 116 of the rotating element 112 be rigidly connected. The second donor wheel 124 can be a connecting element 126 For example, a sleeve 128 , and the connecting element 126 can the second donor wheel 124 stuck with the second part 118 of the rotating element 112 connect. The connecting element 126 in particular, a recess 130 and the second part 118 of the rotating element 112 can be at least partially in the recess 130 be included. Furthermore, the sensor system 110 a sensor element 134 on. The sensor element 134 can be an implementation 136 and the rotating element 112 Can be at least partially in the implementation 136 be included. The sensor element 134 can be below the first sender wheel 122 be arranged. Furthermore, the sensor element 134 stationary with respect to a rotation of the rotating element 112 to be appropriate.

2A and 2 B show schematic representations of embodiments of a first encoder wheel 122 ( 2A) and a second one phonic wheel 124 ( 2 B) , The first donor wheel 122 and the second donor wheel 124 can at least partially the first donor wheel 122 and the second donor wheel 124 according to 1 correspond to the description of the 1 can be referenced.

The first donor wheel 122 according to 2A can have a circular basic shape. The first donor wheel 122 may be at least two first electrically conductive segments 148 and at least two first electrically non-conductive segments 150 respectively. The first electrically conductive segments 148 and / or the first electrically non-conductive segments 150 may be formed in particular planar and transversely, in particular perpendicular to the axis of rotation A extend. The first electrically conductive segments 148 and the first electrically non-conductive segments 150 can be configured as circular sector segments. The first electrically non-conductive segments 150 can as a recess 142 be formed, in particular as a circular sector-shaped recess 142 , The first electrically conductive segments 148 and the first electrically non-conductive segments 150 can each have the same shape. The first electrically conductive segments 148 can each have a first arcuate side 152 and the second electrically non-conductive segments 150 can each have a second arcuate side 154 respectively. The first circular arc-shaped side 152 can be an angle α ₁ span to the rotation axis A and the second circular arc-shaped side 154 can be an angle β ₁ to the axis of rotation A span.

The second donor wheel 124 according to 2 B can have at least two electrically conductive segments 138 and at least two second electrically non-conductive segments 140 respectively. The second electrically conductive segments 138 and the second electrically non-conductive segments 140 can in particular be planar and extend transversely, in particular perpendicular to the axis of rotation A. The second electrically conductive segments 138 and the second electrically non-conductive segments 140 can be configured as circular sector segments. The second electrically non-conductive segments 140 can as a recess 142 be formed, in particular as a circular sector-shaped recess 142 , The segments 138 and the second electrically non-conductive segments 140 can each have the same shape. The second electrically conductive segments 138 can each have a third arcuate side 144 and the second electrically non-conductive segments 140 can each have a fourth arcuate side 146 respectively. The third circular arc-shaped side 144 can be an angle α ₂ to the axis of rotation A span and the fourth arcuate side 146 can be an angle β ₂ to the axis of rotation A span. The second electrically conductive segments 138 and the second electrically non-conductive segments 140 can be within a radius r ₂ be arranged around the axis of rotation. The angle α ₁ and the angle α ₂ can be essentially the same size. The angle β ₁ and the angle α ₁ can be essentially the same size. The angle β ₂ and the angle α ₂ can be essentially the same size.

The second electrically conductive segment 138 may be at least one electrically conductive sub-segment 160 and at least one electrically non-conductive sub-segment 162 respectively. In particular, the electrically conductive sub-segment 160 and the electrically non-conductive sub-segment 162 be formed planar. Furthermore, the electrically conductive sub-segment 160 and the electrically non-conductive sub-segment 162 be at least partially formed as circular sector segments. The electrically non-conductive sub-segment 162 can between the axis of rotation A and the electrically conductive sub-segment 160 be arranged. The electrically non-conductive sub-segment 162 can be within a radius r ₁ around the axis of rotation A be arranged and the electrically conductive sub-segment 160 can be within a radius r ₂ be arranged around the axis of rotation. The electrically conductive subsegment 260 can in particular by at least one outer circular arc-shaped side 164 and 166 limited by at least one inner circular arc-shaped side. The inner circular arc-shaped side 166 may be the electrically non-conductive sub-segment 162 to be facing. The outer circular arc-shaped side 164 can be at a distance to the axis of rotation A be arranged, which is the radius r ₂ equivalent. The inner circular arc-shaped side 166 can be arranged at a distance from the axis of rotation, which is the radius r ₁ equivalent. The inner circular arc-shaped side 166 can to the electrically non-conductive sub-segment 162 adjoin.

In 3A is a schematic representation of a basic structure 172 a sensor element 134 ( 3A) and an exemplary embodiment of a sensor element 134 ( 3B) represents. The sensor element 134 at least largely corresponds to the sensor element 134 as it is in 1 is shown so that at least largely referenced above discussion.

The basic structure 172 , what a 3A is shown, shows an excitation coil 174 , The exciter coil 174 can be configured circumferentially. For clarity, the exciter coil 174 shown as a short circuit without connections. The exciter coil 174 may be configured to be charged with an alternating voltage, which preferably has a frequency of 3.5 MHz.

The basic structure 172 can still have two receiver coils 176 respectively. For clarity, the receiver coils 176 also shown as a short circuit without connections. The receiver coils 176 can be formed at least partially circular segment. In particular, the receiver coils 176 several circle segments 172 include. The basic structure 172 can be a first receiver coil 180 and a second receiver coil 182 include

In principle, each of the illustrated receiver coils 176 circular segments 178 Identify each with an identical radius. This can be made up of a base arc through the points P _a1 . P _m1 and P _i1 or. P _a2 . P _m2 and P _i2 , which by a measuring range δ as well as radii r _a1 . r _i1 and r _m1 (where r _m1 = (r _i1 + r _a1 ) / 2)) as well as r _a2 . r _i2 and r _m2 (where r _m2 = (r _i2 + r _a2 ) / 2)) is defined. Subsequently, this base structure can be rotated by δ / 2 in both directions and limited so that the area defined by δ is not swept over. Conductors in the second plane can be obtained by mirroring the base arc at the bisector of the range defined by δ and re-applying rotation and confinement. Whenever the circular arcs on the radius r _a1 or r _i1 or. r _a2 or r _i2 coincide, a via can be used. In addition, vias may be in the range of the beginning and end of the area defined by δ on the radius r _m1 and r _m2 are located.

For a measurement of the torque and a double angle of rotation, a first additional receiver coil 184 and a second additional receiver coil 186 are used, which each have a rotated by δ / 4 copy of the first receiver coil 180 or the second receiver coil 182 represents, as in 3B shown. Alternatively, three receiver coils can be used, which are then arranged rotated by δ / 3 to each other.

4A to 4B show torque-dependent demodulated signals of the two first receiver coils 180 and the second receiver coils 182 of the sensor system 110 according to 4 , In each case, signals S are shown as a function of the angle W / 360 °.

By crossing over with the first donor wheel 122 and with the second donor wheel 124 can be a coupling between the exciter coil 174 and the receiver coils 180 . 182 . 184 . 186 Depending on the angle of rotation can be influenced. A typical value range of the coupling factor can be between -0.3 and +0.3. By demodulating one in the receiver coils 180 . 182 . 184 . 186 induced signal with a carrier signal (signal of the exciter coil 174 ) can be closed to an amount and a phase of the coupling. The amount can vary continuously with the angle of rotation. The phase angle can ideally be 0 ° or 180 °. By multiplying the magnitude by the cosine of the phase, a substantially offset-free sine / cosine system can be formed, particularly when using two receiver coils with a 90 ° phase shift relative to the measurement range δ. By dividing the two signals and subsequent arctangent calculation, the angle of rotation can be determined. From each two related signals can be calculated by division and ArcTan calculation each an angle. An angular difference can be linear from the torque and thus from a rotation of the first encoder wheel 122 and the second encoder wheel 124 depend. Let the measured angle of the second receiver coils 182 α and the measured angle of the first receiver coils 180 β, then applies to the torque: M = k * (α-β) with k = 1-1000 Nm. In an alternative embodiment, the sensor element 134 each one of the first receiver coils 180 and one of the second receiver coils 182 respectively. Then, with a coil system, the angle of a sensor wheel can be calculated and the phase offset of the corresponding second receiver coil 182 in a relation to the first receiver coil 180 the torque can be calculated (see dashed lines in 4A and 4B) , With relatively small twist angles, it is also possible to recalculate using an ArcSin or ArcCos function knowing the angle. A missing uniqueness of the sinusoidal or cosinusoidal signals can be compensated here by a "sector recognition". In order for such signal forms as well as phase offsets to arise, the first sender wheel and the second sender wheel can be mounted so that they are congruent without the action of a torque in plan view from the direction of the rotating element.

5A to 5C show different views of the first donor wheel 122 and the second encoder wheel 124 in plan view. In 5A No relative rotation is shown in 5B a mean relative twist and in 5C a large relative twist. For maximum sensitivity of the sensor element 134 can be the first donor wheel 122 and the second donor wheel 124 be positioned so rotated relative to each other that they are congruent in the plan view without the action of torque, as in 5A shown. Now it comes to the action of a torque and a relative rotation of the first encoder wheel 122 and the second encoder wheel 124 , In a plan view, a phase shift between the first encoder wheel 122 and the second donor wheel 124 arise, as in 5A and 5B shown. A size of the offset can influence the angular difference and thus the phase offset of the signals, from which the torque can then be derived.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012213539 A1 [0002]
• DE 102004019379 A1 [0003]

Claims (10)

Sensor system (110) for determining at least one rotational property of an element (112) rotating about at least one axis of rotation A, wherein the sensor system (110) comprises: - at least one first encoder wheel (112), the first encoder wheel (112) having at least one first part (116) of a rotating element (112) is connectable, wherein the first encoder wheel (112) at least two first electrically conductive segments (148) and at least two first electrically non-conductive segments (150), which are each arranged radially about the axis of rotation A. ; - At least a second encoder wheel (124), wherein the second encoder wheel (124) with at least a second part (118) of the rotating element (112) is connectable; - At least one torsion element (120), wherein the first part (116) and the second part (118) by the torsion element (120) are rotatably coupled to each other; - At least one sensor element (134), wherein the sensor element (134) is arranged, a relative rotation of the first encoder wheel (112) and the second encoder wheel (124) to each other depending on a Überdeckungsmaß the first electrically conductive segments (148) and the second electrically determine conductive segments (138); characterized in that the second encoder wheel at least two second electrically non-conductive segments (140) and at least two second electrically conductive segments (138), which are each arranged radially about the axis of rotation A, wherein the second electrically conductive segments (138) each at least an electrically conductive sub-segment (160) and at least electrically non-conductive sub-segment (162). Sensor system (110) according to the preceding claim, wherein the electrically non-conductive sub-segment (162) is arranged within a radius r ₁ about the axis of rotation A, wherein the electrically conductive sub-segment (160) is arranged within a radius r ₂ about the axis of rotation A, where r ₁ <r ₂ . Sensor system (110) according to the preceding claim, wherein the first electrically conductive segments (148) are arranged within a radius r ₃ about the axis of rotation A, wherein r ₁ and r ₃ are substantially equal in size. Sensor system (110) according to the preceding claim, wherein: r ₃ ≤ r ₂ . The sensor system (110) of any one of the preceding claims, wherein at least one segment selected from the group consisting of the second electrically conductive segments (138), the first electrically conductive segments (148), the second electrically non-conductive segments (140), the first electrically non-conductive segments (150), at least partially formed as a circular sector segment. Sensor system (110) according to one of the preceding claims, wherein the first electrically non-conductive segments (150) at an angle α ₁ are spaced from each other, wherein the second electrically non-conductive segments (140) at an angle α ₂ are spaced from each other, wherein α ₁ and α ₁ are substantially equal. A sensor system (110) according to any one of the preceding claims, wherein the first electrically conductive segments (148) are spaced apart at an angle β ₁ , the second electrically conductive segments (138) being spaced apart at an angle β ₂ , wherein in β ₁ and β ₂ are substantially equal. Sensor system (110) according to one of the preceding claims, wherein the first encoder wheel (112) has a diameter d ₁ , wherein the second encoder wheel (124) has a diameter d ₂ , wherein d ₂ > d ₁ . A sensor system (110) according to any one of the preceding claims, wherein the sensor element (134) comprises at least one excitation coil (174), at least one first receiver coil (180) and at least two second receiver coils (182) or at least two of the first receiver coils (180) and at least one the second receiver coils (182). Method for determining at least one rotational property of an element (112) rotating about at least one axis of rotation A, the method comprising using at least one sensor system (110) according to one of the preceding claims, the method further comprising the following steps: a) receiving inductive signals by means of the sensor element (134); and b) evaluating the inductive signals and determining the rotation property by means of the inductive signals.

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