DE102014218712A1 - Rotation angle detection device based on polarization effect - Google Patents

Abstract

The invention relates to a rotation angle detection device (42) for detecting a rotation angle (28) based on a transmitter radiation (45), comprising: - a radiation source (44) arranged radially from the rotation axis (29) for emitting the transmitter radiation (45) at least in the axial direction parallel to the axis of rotation (29), - a polarization element (46) arranged radially from the rotation axis (29), which is set up, based on the transmitter radiation (45) radiation (49) with a polarization dependent to generate the angle of rotation (28) to be detected, and - a sensor (51) for outputting a measurement signal (50) dependent on the angle of rotation (28) to be detected based on the polarized radiation (49), wherein the radiation source (44) and the Polarization element (46) are arranged to be detected rotation angle (28) against each other movable.

Description

The invention relates to a rotation angle detection device for detecting a rotation angle of an object about a rotation axis and an electric motor with the rotation angle detection device.

From the DE 10 2009 005 536 a rotation angle detecting device for detecting a rotation angle of an object about an axis of rotation is known, comprising an optical radiation source and a detector, wherein in the beam path between the radiation source and the detector, a shading structure connected to the object is arranged, which the beam path in dependence on the to be detected Shading angle. The detector performs an evaluation of the shading pattern and determines the angle of rotation to be detected based thereon.

It is an object of the invention to improve the known structure.

The object is solved by the features of the independent claims. Preferred developments are the subject of the dependent claims.

• – ein radial von der Rotationsachse beabstandet angeordnetes, mit dem drehbaren Objekt mechanisch verbindbares Polarisationselement, das eingerichtet ist, basierend auf der Geberstrahlung eine Strahlung mit einer drehwinkelabhängigen Polarisation zu erzeugen, und
• – einen Messaufnehmer zur Ausgabe eines vom zu erfassenden Drehwinkel abhängigen Messsignals basierend auf der polarisierten Strahlung,
• – wobei die Strahlenquelle und das Polarisationselement um den zu erfassenden Drehwinkel gegeneinander beweglich angeordnet sind.

According to one aspect of the invention, a rotation angle detecting device based on the polarization effect for detecting a rotation angle of an object about a rotation axis comprises a radiation source radially spaced from the rotation axis for emitting the sensor radiation in the axial direction parallel to the rotation axis.

• - A radially spaced from the axis of rotation arranged, with the rotatable object mechanically connectable polarization element, which is adapted to generate based on the encoder radiation radiation with a rotation angle-dependent polarization, and
• A sensor for outputting a measurement signal dependent on the angle of rotation to be detected, based on the polarized radiation,
• - Wherein the radiation source and the polarization element are arranged so as to be movable relative to one another about the angle of rotation to be detected.

A disadvantage of the rotational angle detection device specified at the outset as prior art is that the brightness evaluation can be influenced by brightness fluctuations of the optical radiation source as a matter of principle, which can lead to correspondingly high inaccuracies in the detection of the rotational angle.

The specified rotation angle detection device attacks this finding with the consideration of not changing the brightness of the radiation for detecting the angle of rotation but rather its polarization, because it can not be influenced by fluctuations in the emission of the radiation from the radiation source. Therefore, by detecting the rotation angle based on the polarization of the radiation, a robust sensor can be easily provided.

In a development of the specified rotation angle detection device, the radiation source is an optical radiation source which emits light waves which can be described as electromagnetic transversal waves, wherein each wave is associated with a direction of polarization orthogonal to the direction of propagation. Optical radiation is not affected by other donor fields, such as magnetic fields, so that the sensor can hardly be disturbed even in the vicinity of other sensors. In addition, it is advantageous that light waves do not generate any donor fields which disturb the other sensors.

In another development of the specified rotation angle detection device, the polarization element can be set up to emit polarized radiation with a rotation angle-dependent preferred direction when it is exposed to a transmitter radiation. Preferably unpolarized donor radiation is used, which means that waves of all polarization directions are represented in the donor radiation. A preferred direction should be understood as the most frequently occurring direction of polarization of the waves emitted. An ideal polarizer would only emit waves that swing exactly in one direction, real polarizers emit a mixture of waves with a preferential direction. If the polarization element rotates about the angle of rotation to be detected, then the preferred direction of the emitted radiation also rotates, in which case only this preferred direction must be detected in order to determine the angle of rotation.

In order to detect the preferred direction of the radiation emitted by the polarization direction, the rotation angle detection device according to the invention comprises a sensor with preferably a plurality of detectors which are adapted to respond to different polarization directions with different sensitivity.

To concretize the formation of the polarization element different approaches are possible. For example, it would be conceivable to use a polarizing beam splitter. In a preferred embodiment of the specified rotation angle detection device, the polarization element is a polarizing filter disk for generating the polarized radiation by filtering the Donors radiation. Such a polarizing filter disk is inexpensive, easy and failsafe usable in the specified rotation angle detecting device.

In an additional development, the specified rotation angle detection device comprises a reflection element which, starting from the radiation source, is arranged behind the polarization filter disk and is set up to reflect back the filtered transmitter radiation. In this way, the radiation source and the measuring devices can be arranged axially on the same side and thus on the same carrier, whereby the mechanical and also the electrical connection in the rotation angle detecting device can be simplified.

In a further development of the specified rotation angle detection device, the sensor comprises at least one light intensity detector which is set up to output its measurement signal as a function of the intensity of the radiation incident on it. For example, the light intensity detector could be made sensitive in a particular polarization direction. Then rotates the above-mentioned preferred direction relative to the polarization direction in which the light intensity detector is designed sensitive, detects the light intensity detector depending on the angular position between the preferred direction of the polarized radiation and the polarization direction of the light intensity detector, a different light intensity and thus outputs the rotation angle-dependent measurement signal.

Alternatively, in a particular embodiment of the disclosed rotation angle detecting apparatus, the polarization direction sensitive light intensity detector could be formed of a transmission polarization filter and a non-polarization direction sensitive light intensity detector, so that a simpler light intensity detector could be used.

In an additional development, the specified rotation angle detection device comprises a further light intensity detector in the sensor and a further transmission polarization filter between the polarization element and the further light intensity detector, wherein the transmission polarization filter and the further transmission polarization filter are arranged to pass the polarized radiation in different radiation planes. The use of a further light intensity detector in conjunction with a further transmission polarization filter makes it possible to detect not only the angle of rotation itself but also the change in the angle of rotation, such as the direction of rotation.

Therefore, the sensor should expediently be set up to determine the measurement signal based on a light intensity, determined by the light intensity detector and the further light intensity detector, of the polarized radiation filtered by the transmission polarization filters.

In principle, any number of transmission polarization filters and light intensity detectors for detecting the polarized radiation can be used in the sensor, but the individual transmission polarization filters should allow all the polarized radiation to pass through in different radiation planes. The use of a plurality of transmission polarization filters and light intensity detectors has the advantage that the rotation angle can be detected with sufficient precision even if the light intensity detectors used have a different photosensitivity.

• – einen Stator,
• – einen relativ zum Stator drehbar angeordneten Rotor,
• – eine Antriebseinrichtung zum Erzeugen eines elektromagnetischen Drehfeldes zur Erzeugung eines zwischen Rotor und Stator wirkenden Drehmoments basierend auf einem Drehwinkel des Rotors relativ zum Stator, und
• – eine der angegebenen Drehwinkelerfassungsvorrichtungen zum Erfassen des Drehwinkels für die Antriebseinrichtung.

In accordance with another aspect of the invention, an engine includes

• A stator,
• A rotor rotatable relative to the stator,
• A drive device for generating an electromagnetic rotary field for generating a torque acting between rotor and stator based on a rotational angle of the rotor relative to the stator, and
• - One of the specified rotation angle detecting devices for detecting the rotation angle for the drive device.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in connection with the drawings, wherein:

1 a schematic diagram of a vehicle with a service brake,

2 a schematic diagram of a pump with an attached motor in the context of a central brake pressure supply for the service brake of the vehicle 1 .

3 a schematic diagram of the engine of 2 .

4 a schematic diagram of an angle sensor in the engine of 2 in a first state,

5 a schematic diagram of an angle sensor in the engine of 2 in a second state,

6 a schematic diagram of an angle sensor in the engine of 2 in a third state,

7 a schematic diagram of an angle sensor in the engine of 2 in a fourth state, and

8th a schematic diagram of an angle sensor in the engine of 2 in a fifth state show.

In the figures, the same technical elements are provided with the same reference numerals and described only once.

The invention is exemplified below in an in 2 shown engine 1 described, which is set up in 1 shown pump 2 head for. However, this embodiment is only to be seen as an example because the invention can be used in any technical field.

It will open 1 Reference is made to a schematic diagram of a vehicle 3 with four hydraulic brake control loops shows. These hydraulic brake control circuits are in 1 Mistake.

The vehicle 3 has a chassis 4 on, on a road not shown on four wheels 5 can be driven driven by a motor, not shown. The individual wheels 5 are in the present embodiment hydraulically actuated brake effectors 6 assigned to the vehicle 3 Delay from the ride out and hold at a standstill. The brake effectors comprise friction surfaces that rotate with the wheel and non-rotatably arranged friction linings which are connected via hydraulic wheel brake cylinders 7 can be pressed against the friction surfaces.

Actuation of the brake effectors 6 is by the driver of the vehicle 3 via a brake pedal 8th initiated by the driver on the brake pedal 8th occurs. The brake pedal 8th is over a push rod 9 with a brake system pressure delivery module 10 connected to a brake system pressure via a brake system pressure line 13 gives off and that from a reservoir 11 supplied with hydraulic fluid. In addition, the brake system pressure delivery module 10 via a pump pressure line 12 with one through the electric motor 1 driven pump 2 connected. For example, the brake system pressure delivery module 10 set up via the brake system pressure line 13 to deliver a pressure composed of a pedal force component and a pump pressure component additive. Thus, a hydraulic amplification of a pedal operation and automatic braking interventions of assistance systems can be realized.

The via brake system pressure line 13 provided hydraulic fluid is an electro-hydraulic pressure control device 14 supplied, as for example, from the DE 10 2005 059 941 A1 is known. In this electrohydraulic pressure control device 14 is for each brake pressure cylinder 7 based on an individual operating pressure to be described later 15 an individual operating pressure 16 set. These are in the electro-hydraulic pressure control device 14 a common drive device 17 and for every brake pressure cylinder 7 a control valve 18 and a hydraulic pressure sensor 19 arranged. The pressure sensors 19 capture the operating pressure 16 the hydraulic fluid in each of the brake pressure cylinders 7 leading hydraulic fluid lines. The drive device 17 compares the recorded operating pressures 16 with the operating set pressures 15 for the corresponding brake pressure cylinder 7 and controls the respective control valves 18 with corresponding valve control signals 20 in the context of each control valve 18 of a deviation between his operating pressure 16 and its operating pressure 15 depend. In this way, in each brake pressure cylinder 7 the operating pressure 16 to the operating pressure 15 equalized.

The operating set pressures 15 can from a parent controller 21 be specified. This higher-level control device 21 can the operating set pressures 15 pretend that by the brake effectors 6 caused braking force suitable for the individual wheels 5 of the vehicle 3 is distributed. An example of this is in the WO 2004/022 396 A1 why this should not be described in detail.

Alternatively or additionally, the operating set pressures 15 are also specified in the context of a superimposed speed control loop, such as anti-lock braking system (see DE 16 554 32 A ) and / or as driving dynamics control (see DE 10 2011 080 789 A1 ) is known. In the context of this superimposed speed control loop, the higher-level control device receives 21 of wheel speed sensors 22 Istraddrehzahlen 23 with which the individual wheels 5 of the vehicle 3 rotate. Within the parent control device 21 could then be based on the actual wheel speeds 23 determines a suitable control variable, which then by specifying the operating set pressures 15 could be adjusted as a manipulated variable to a corresponding desired size. In the case of the antilock braking system could be a controlled variable, for example Slippage of the wheels 5 and in the case of vehicle dynamics control, the yaw rate of the vehicle 3 to get voted. Since this is known from the publications cited above, a detailed explanation thereof for the sake of brevity should be omitted.

It will open 2 and 3 Referred to the engine 1 and the pump connected to it 2 show in a schematic view.

The motor 1 includes a stator 24 and one rotatable in the stator 24 recorded rotor 25 with a shaft to which axially a first clutch disc 26 followed. In the first clutch disc 26 axially engages a second clutch disc 27 a, then a rotation of the rotor 25 with a rotation angle 28 around a rotation axis 29 on a machine, here in the form of the pump 2 can transfer.

In the present embodiment, the engine is 1 designed as electronically commutated electric motor.

In the context of an electronically commutated electric motor, an electromagnetic rotating field, not further described, is used as the exciting field between the stator 24 and the rotor 25 of the motor 1 based on the angle of rotation 28 of the rotor 25 opposite the stator 24 of the motor 1 generated. In the context of the present embodiment, this excitation field is generated by a drive device which has a commutation device 31 and in 3 illustrated motor windings 32 includes. The commutation device 31 controls phase currents 33 the motor windings 32 , for example, in a manner known per se stationary on the stator 24 can be arranged. The motor windings 32 then generate in a conventional manner based on the phase currents 33 the exciter field.

If the exciter field stationary in the stator 24 generated, then should be stationary on the rotor 25 present a further magnetic field, for example via a permanent magnet with a north pole 34 and a south pole 35 , It can poles 34 . 35 over a sleeve 36 held together. When the magnetic fields of the rotor and stator are at an angle to each other, a magnetic moment acts between the two bodies and the rotor 25 is opposite the stator 24 driven. Thus, the phase currents have to generate a present not only in the current angle of rotation drive torque 33 from the commutation device 31 be excited so that that of the motor windings 32 at the stator 24 induced excitation field always (ie at arbitrary angles of rotation) at an angle to that of the poles 34 . 35 excited magnetic field stands. Therefore, the commutation must 31 for generating the phase currents 33 the angle of rotation 28 of the rotor 25 relative to the stator 24 know about the phase currents 33 set in accordance with the previously explained specification.

Based on the rotation angle 28 can be a control device 37 in the commutation device 31 with suitable control signals 38 switch 39 trigger a known bridge circuit to a supply voltage 40 to the motor windings 32 to create and thus coil currents 41 to control the generation of the exciter field.

The angle of rotation 28 is used in the present embodiment with an angle sensor below 42 said rotation angle detecting device detects, which in a radial distance 43 to the axis of rotation 29 is arranged and with a radiation source in the form of a light source 44 axially in the direction of the first clutch disc 26 a donor radiation in the form of unpolarized light 45 emits. The angle sensor 42 further includes a rotationally fixed with the first clutch disc 26 and thus with the rotor 25 connected polarization element 46 in the form of a polarization filter ring. The Polfilterreflexionsring can from a polarizing filter 47 and one axially between the clutch disc 26 and the polarizing filter 47 arranged reflection element 48 be constructed.

For detecting the angle of rotation 28 becomes the unpolarized light 45 from the polarization element 46 as polarized radiation in the form of polarized light 49 thrown back. Since the polarization element 46 with the rotor 25 is a preferred direction of polarization of the reflected polarized light 49 from the angle of rotation 28 dependent. By detecting the preferred direction of the polarization of the reflected light, the angle sensor 42 Therefore, a dependent of the rotation angle measurement signal 50 output.

This will be explained below on the basis of 3 to 10 be made clearer.

For detecting the preferred direction of the polarization of the reflected light 49 is in the angle sensor 42 a sensor 51 present to the rotor 25 opposite stationary to the stator 24 is attached.

The sensor 51 has a first light intensity detector 52 , a second light intensity detector 53 and a third light intensity detector 54 , Between the first light intensity detector 52 and the polarization element 46 is a first transmitted-light polarizing filter 55 arranged while between the second light intensity detector 53 and the polarization element 46 a second transmitted polarization filter 56 and between third light intensity detector 54 and the polarizing element 46 a third transmitted-light polarizing filter 57 is arranged.

The three transmitted-light polarizing filters 55 . 56 . 57 filter the reflected and polarized light 49 in different polarization directions. For example, the first transmitted-light polarization filter 55 the reflected and polarized light 49 in a given plane of polarization while the second transmitted polarization filter 56 the reflected and polarized light 49 in a plane of polarization of the first transmitted-light polarizing filter 55 rotated by 45 ° polarization plane and the third transmitted light polarizing filter 57 the reflected and polarized light 49 in a plane of polarization of the first transmitted-light polarizing filter 55 can filter by 90 ° rotated polarization plane.

During the first light intensity detector 52 based on the reflected and polarized light 49 after the first transmitted-light polarizing filter 55 a first intermediate signal 58 can output the second light intensity detector 53 based on the reflected and polarized light 49 after the second transmitted-light polarizing filter 56 a second intermediate signal 59 and the third light intensity detector 54 based on the reflected and polarized light 49 after the third transmitted light polarizing filter 57 a third intermediate signal 60 output.

The signal values of the individual intermediate signals 58 . 59 . 60 from the individual light intensity detectors 52 . 53 . 54 are in the 3 to 10 through small black bars 61 indicated, with a full black bar 61 a full swing for the respective intermediate signal 58 . 59 . 60 , half a black bar 61 for a half-rash for the respective intermediate signal 58 . 59 . 60 and a missing black bar 61 for no deflection of the respective intermediate signal 58 . 59 . 60 stands.

The following is from a zero position 62 for the rotor 25 and thus also the polarization element 38 be assumed, in which the polarization element 46 the reflected light 49 polarized in a preferred direction, the in 4 to 8th with the reference number 63 is indicated. The first transmitted-light polarizing filter 55 is arranged with its preferred direction in the same direction as the preferred direction 63 of the polarization element 46 in the zero position 62 and the remaining transmitted-light polarizing filters 56 . 57 in the aforementioned manner. The polarization filters 55 . 56 . 57 let through light whose polarization coincides with the direction of preferential polarization or something deviates from it, with all the more light absorbed - that is, not transmitted, the greater this angular deviation is. The polarization filter has a transmission coefficient dependent on the angular deviation, which is defined as the quotient of transmitted light intensity divided by the incident light intensity. In this connection, it should be mentioned that a real polarizing filter does not transmit light polarized exactly in its preferential polarization direction without some shadowing effect and does not completely absorb light polarized exactly perpendicular to its preferential polarization direction. However, in the former case, the transmission coefficient is maximum (slightly less than 1) and in the latter case minimal (slightly larger than 0).

In the zero position 62 becomes the unpolarized light 45 through the polarization element 46 in the plane of polarization of the first transmitted-light polarizing filter 55 polarized and so as the polarized light 49 thrown back. This happens with the polarized and reflected light 49 the first transmitted-light polarizing filter 55 with the maximum transmission coefficient, the second transmitted-light polarization filter 56 with a mean transmission coefficient and the third transmitted light polarization filter 57 with the minimum transmission coefficient, which is in 4 by the bars 61 you can see.

An evaluation circuit 64 can the combination of intermediate signals 58 . 59 . 60 in the 4 state then corresponding to a value for the rotation angle 28 associate, which implies that the rotor 25 exactly at the zero position 62 is, and a corresponding measurement signal 50 output in an analog or digital manner. This value for the angle of rotation 28 of the rotor 25 in the zero position 62 is usually 0 °.

Be the rotor 25 and thus the polarization element 46 , as in 5 shown to a rotation angle 28 from 45 ° to the zero position 62 turned further, then becomes the unpolarized light 45 in this first angular position 65 through the polarization element 46 in the plane of polarization of the second transmitted-light polarizing filter 56 polarized and so as the polarized light 49 thrown back. This happens with the polarized and reflected light 49 the first transmitted-light polarizing filter 55 with a mean transmission coefficient, the second transmitted-light polarization filter 56 with the maximum transmission coefficient and the third transmitted light polarization filter 57 also with a mean transmission coefficient, which is in 5 by the bars 61 you can see.

The evaluation circuit 64 can the combination of intermediate signals 58 . 59 . 60 in the 4 state then corresponding to a value for the rotation angle 28 of 45 ° and the measurement signal 50 correspondingly output from 45 °.

Be the rotor 25 and thus the polarization element 46 , as in 6 shown opposite to the zero position 46 around a rotation angle 28 rotated by 90 °, so does the unpolarized light 45 in this second angular position 66 through the polarization element 46 in the plane of polarization of the third transmitted-light polarizing filter 57 polarized and so as the polarized light 49 thrown back. This happens with the polarized and reflected light 49 the first transmitted-light polarizing filter 55 with the minimum transmission coefficient, the second transmitted-light polarization filter 56 with a mean transmission coefficient and the third transmitted light polarization filter 57 with the maximum transmission coefficient, which is in 5 by the bars 61 you can see.

The evaluation circuit 64 can the combination of intermediate signals 58 . 59 . 60 in the 6 state then corresponding to a value for the rotation angle 28 of 90 ° and the measurement signal 50 correspondingly output from 90 °.

Be the rotor 25 and thus the polarization element 46 , as in 7 shown opposite to the zero position 62 around a rotation angle 28 rotated by 135 °, so does the unpolarized light 45 in this third angular position 67 through the polarization element 46 opposite to the polarization plane of the second transmitted-light polarizing filter 56 polarized and so as the polarized light 49 thrown back. This happens with the polarized and reflected light 49 the first transmitted-light polarizing filter 55 with a mean transmission coefficient, the second transmitted-light polarization filter 56 with the minimum transmission coefficient and the third transmitted light polarization filter 57 also with a mean transmission coefficient, which is in 7 by the bars 61 you can see.

The evaluation circuit 64 can the combination of intermediate signals 58 . 59 . 60 in the 7 state then corresponding to a value for the rotation angle 28 of 135 ° and the measuring signal 50 according to output from 135 ° depending.

Be the rotor 25 and thus the polarization element 46 , as in 8th shown opposite to the zero position 62 around a rotation angle 28 rotated further by 180 °, the situation corresponds to the polarization in this fourth angular position 68 exactly the polarization in the zero position 62 so that the combination of the intermediate signals 58 . 59 . 60 in the 8th state not shown by the combination of the intermediate signals 58 . 59 . 60 in the 4 shown state can be distinguished.

Around the angle of rotation 28 Nevertheless, to be able to detect over a value range of greater than 180 ° could, for example, within the evaluation circuit 64 a counter can be used, which then at each 180 ° rotation to 1 is counted up, so that the angle of rotation 28 in the case of an even count, for example, before 180 ° and an odd count after 180 °. The rotation angle detection device is preferably used in electric motors whose excitation field has a 180 ° periodicity. In this case, no such counter is needed.

It should be noted that the polarized light 49 does not necessarily have to be linearly polarized. In principle, for example, an elliptical polarization of the unpolarized light would be 45 possible, but with the linearly polarized light 49 the highest sensitivity in the measurement signal 50 for the rotation angle 28 can achieve.

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 102009005536 [0002]
• DE 102005059941 A1 [0033]
• WO 2004/022396 A1 [0034]
• DE 1655432A [0035]
• DE 102011080789 A1 [0035]

Claims (10)

Rotation angle detection device ( 42 ) for detecting a rotation angle ( 28 ) based on a transmitter radiation ( 45 ), comprising: - a radially of the axis of rotation ( 29 ) ( 43 ) arranged radiation source ( 44 ) for dispensing the transmitter radiation ( 45 ) at least in the axial direction parallel to the axis of rotation ( 29 ), - radially from the axis of rotation ( 29 ) ( 43 ) arranged polarization element ( 46 ), which is set up based on the donor radiation ( 45 ) a radiation ( 49 ) with a polarization depending on the angle of rotation to be detected ( 28 ), and - a sensor ( 51 ) for outputting a rotational angle to be detected ( 28 ) dependent measurement signal ( 50 ) based on the polarized radiation ( 49 ), - whereby the radiation source ( 44 ) and the polarization element ( 46 ) about the angle of rotation to be detected ( 28 ) are arranged movable against each other. Rotation angle detection device ( 42 ) according to claim 1, wherein the radiation source ( 44 ) is an optical radiation source. Rotation angle detection device ( 42 ) according to claim 1 or 2, wherein the polarization element ( 46 ) is adapted to the polarized radiation ( 49 ) with a rotation angle-dependent preferred direction. Rotation angle detection device ( 42 ) according to one of the preceding claims, wherein the polarization element ( 46 ) a polarizing filter ( 47 ) for generating the polarized radiation ( 49 ) by filtering the donor radiation ( 45 ). Rotation angle detection device ( 42 ) according to one of the preceding claims, comprising a reflection element ( 48 ) starting from the radiation source ( 44 ) behind the polarizing filter ( 47 ) is arranged and set up, the filtered transmitter radiation ( 45 ) to throw back. Rotation angle detection device ( 42 ) according to one of the preceding claims, wherein the sensor ( 51 ) a radiation intensity detector ( 52 . 53 . 54 ), which is adapted to the measurement signal ( 50 ) as a function of the intensity of the polarized radiation ( 49 ). Rotation angle detection device ( 42 ) according to claim 6, comprising a transmission polarization filter ( 55 . 56 . 57 ) between the polarization element ( 46 ) and the radiation intensity detector ( 52 . 53 . 54 ). Rotation angle detection device ( 42 ) according to claim 7, comprising a further radiation intensity detector ( 52 . 53 . 54 ) in the sensor ( 51 ) and another transmission polarization filter ( 55 . 56 . 57 ) between the polarization element ( 46 ) and the further radiation intensity detector ( 52 . 53 . 54 ), wherein the transmission polarization filter ( 55 . 56 . 57 ) and the further transmission polarization filter ( 55 . 56 . 57 ), the polarized radiation ( 49 ) in different radiation levels. Rotation angle detection device ( 42 ) according to claim 8, wherein the sensor ( 51 ), the measuring signal ( 50 ) based on a radiation intensity detector ( 52 . 53 . 54 ) and the further radiation intensity detector ( 44 . 45 . 46 ) determined radiation intensity of the through the polarizing filters ( 55 . 56 . 57 ) filtered polarized radiation ( 49 ). Engine ( 1 ) comprising: a stator ( 24 ), - a rotor rotatably mounted relative to the stator ( 25 ), - a drive device ( 31 . 32 ) for generating an electromagnetic rotating field for generating an between rotor ( 25 ) and stator ( 24 ) acting torque based on a rotation angle ( 28 ) of the rotor ( 25 ) relative to the stator ( 24 ), and - a rotation angle detection device ( 42 ) according to one of the preceding claims for detecting the angle of rotation ( 28 ) for the drive device ( 31 ).

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