WO2018001411A1

WO2018001411A1 - Method and device for measuring an angular position for a clutch release system having a sensor having different measurement ranges

Info

Publication number: WO2018001411A1
Application number: PCT/DE2017/100521
Authority: WO
Inventors: Ömer Kochan; Wolfgang Käshammer; Jie Zhou
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2016-06-27
Filing date: 2017-06-21
Publication date: 2018-01-04
Also published as: DE102016211448A1; DE112017003182A5

Abstract

The invention relates to a method for measuring the angular position of a rotor (4) relative to a stator (3) of a clutch release system (2) of a motor vehicle, wherein an electric sensor (6) for detecting at least one magnet present on the rotor (4) is used in such a way that the angular position of the rotor (4) to the stator (3) is detected, wherein the sensor (6) has different measurement ranges, of which one measurement region is pre-set in a targeted manner onto the magnetic field (5) acting on the sensor (6). The invention further relates to a rotor position sensor assembly (1) for a clutch release system (2), having a rotor (4) that is rotatable relative to a stator (3), wherein on the stator (3), an electric sensor (6) is mounted, which is prepared for detecting a magnetic field generated by the at least one magnet (5). The electric sensor (6) has different, specific selectable measurement ranges, of which one is selected as a function of the magnetic field acting on the sensor. The invention further relates to a clutch release system (2) having a rotor position sensor assembly (1) according to the invention.

Description

Method and device for measuring an angular position for a clutch release system with a sensor with different measuring ranges

The present invention relates to a method for measuring an angular position of a rotor relative to a stator for a clutch release system of a motor vehicle, wherein an electrical sensor for detecting at least one magnet present on the rotor is used so that the angular position of the rotor is detected to the stator and a Rotor bearing sensor assembly for a Kupplungsausrückungs- system, with a relative to a startable rotor, wherein at the start of an electric sensor is mounted, which is prepared for detecting a caused by the at least one magnet magnetic field. The invention also relates to a clutch release system.

A rotor position sensor of an electronically central disengager is used as a basic measuring device in the commutation of an engine or the positioning of a clutch. This essentially comprises a magnet ring / magnetic encoder ring with several pole pairs as well as two analogue Hall sensors and three Switch Hall sensors. DE 10 2014 218 544 A1 discloses a sensor unit for determining a rotor position of an electric motor and an electric motor, preferably for a clutch actuator of a clutch actuation system of a motor vehicle, which relates to a sensor unit for determining a rotor position of an electric motor which comprises at least one magnetic field sensor. which is fastened on a carrier element. In the case of a sensor unit in which the sensor system is easily exchangeable, the carrier element is positioned in a sensor housing which is open on one side and has a sensitive surface of the at least one magnetic field sensor in the direction of the open-form side of the sensor housing. From DE 10 2013 203 388 B3 a rotor position sensor for an electronically commutated electrical machine with a reference encoder is known. It relates to a rotor position sensor for a stator and a rotor having electronically commutated electrical machine comprising a stator rotatably mounted on the stator motor rotor position sensor for detecting the rotational position of the rotor relative to the magnetic field of the stator and a rotatably mounted on the rotor signal generator. The rotor position sensor disclosed therein is characterized in that it has a reference transmitter for detecting reference values of the magnetic flux density of the rotor field, the reference values serving for determining an angular offset between the signal generator and the position of the rotor.

In an older sensor assembly, five sensors are mounted on one side of a board and stabilized by a steel body. The assembly can be done only from the actuator side due to the small installation space. Since the analog sensors have a narrow measuring range and the axial tolerance between the sensitive elements and the magnet surface is very large, the sensor has been mechanically compensated by an additional spacer disk.

A problem with this is that after inserting the sensor into the stator, it can no longer be removed without destroying it. Once a sensor or connection is broken, the entire clutch release system is no longer functional. Therefore, a solution must be found to provide an exchangeable and a small space requiring sensor assembly. Furthermore, a further adaptation of the sensor assembly has hitherto been difficult due to the mounting direction and the seal required thereby relative to the transmission side.

It is the object of the invention to eliminate or at least mitigate the disadvantages of the prior art and, in particular, to provide a method and a device which requires less space with good mounting capability and measures precisely. Furthermore, a method for electronically compensating an axial offset of an analog Hall sensor is to be provided. The object of the invention is achieved in a generic method in that the sensor has different / variable measuring ranges or measuring stages, from which a measuring range or a measuring stage is preset to the magnetic field acting on the sensor / preselected. By the invention Although the concept increases permissible axial tolerance between the electrical sensor / sensitive element and the magnetic surface, but it is a compact and mounted from the front side of the carrier Rotorlagesensorbaugrupe created. A further adaptation of the sensor assembly is at least better possible.

Advantageous embodiments are claimed in the subclaims and are explained below.

Any disclosure in the context of the inventive method for measuring an angular position for a clutch release system for a vehicle also applies to the inventive device for measuring an angular position for a clutch release system for a vehicle, as well as any disclosure in connection with the inventive device for measuring an angular position for a clutch release system for a vehicle also applies to the method according to the invention for measuring an angular position for a clutch release system for a vehicle.

So it is advantageous if such a measuring range is selected, which covers the magnetic field acting on the sensor to approximately or exactly 100% of its strength or approximately / exactly (120% or) 140% of its strength. As a result, the entire magnetic field can be detected and processed by the sensor without a detection area being cut off or not taken into account due to the limited detection of the magnetic field by a sensor. By covering the measuring range with a strength of 120%, the measuring signal is given a certain amount of leeway, so that the maximum amplitude of the magnetic field does not have to exploit the maximum of the measuring range. Among other things, this feature accounts for the setting of a sensor to have a manufacturer-specified diagnostic range which should not be used, i. An amplitude of a measured signal just would not lie in a measuring range of the sensor reserved as a diagnosis area.

It is also advantageous that the individual selectable and adjoining measuring ranges overlap by at least 50%. This will create a derte resolution of an output signal ensures. It can thus be switched from one measuring range to the next measuring range, in other words, the measuring range can be selectively changed without falling below a required resolution for a given strength of a magnetic field at a measuring range.

It has proved to be advantageous if a preferably analogue Hall sensor is used as the electrical sensor. Of course, the electrical sensor may also have two, three, four, and in particular five or more Hall sensors. Hall sensors are widely used, inexpensive and have a small space requirement. These Hall sensors are available in various variants and various specifications, which in the present invention are in particular in a measuring range between +/- 6 mT and +/- 200 mT. In particular, the analog Hall sensor has at least six variable measuring ranges. Of course, the measuring range of the Hall sensor can also have other measuring ranges and a different number of measuring range settings. It may, for example, also have a lower limit of +/- 1 mT and / or an upper limit of +/- 1 T. The number of measuring ranges may in particular be three, four, five, six, ten, twenty or more. It has proved to be advantageous if the measuring range or the measuring stage is selected as a function of the distance of the electrical sensor to the magnet defined in the longitudinal direction of the coupling release system. The magnetic field of a magnet decreases over the distance, usually non-linearly. An amplitude of a magnetic field measured by the sensor, in which the distance between the electrical sensor and the magnet is smaller, is therefore greater than an amplitude of a magnetic field measured by the sensor, in which the distance between the electrical sensor and the magnet is greater. A sensor with a large measuring range, for example +/- 200 mT, is therefore used with a small distance from magnet to sensor, whereas with a relatively large distance from magnet to sensor, a sensor with a small measuring range, for example + / - 6 mT is selected. The amplitude of the magnetic field becomes smaller at an increasing distance. In the present invention, a single electrical sensor can adjust the measuring range according to the magnetic field. In addition to the method for measuring an angular position for a clutch release system, the invention also relates to a device for measuring an angular position for a clutch release system with a sensor having different measurement ranges.

The object of the invention is achieved in a generic rotor position sensor assembly for a clutch release system, characterized in that the electrical sensor has different selectively selectable measuring ranges, one of which is selected depending on the magnetic field acting on the sensor.

In this case, it has proved to be advantageous that the electrical sensor is fastened from an end face of a carrier on the carrier or a stator-fixed component, engages in or passes through in order to come into operative contact with the at least one magnet and the rotor from an opposite Front side of the carrier / carrier component statornah and sensornah arranged / mounted. Although this increases the axial tolerance between the sensitive element / electrical sensor and the magnet surface, this arrangement allows mounting from one end face of a carrier, wherein the rotor is arranged on the opposite end face of the carrier. Replacement in the event of a defect or maintenance is thus easier. In addition, a complete seal against the rotor space can be achieved.

An advantageous embodiment provides that a plurality of magnets arranged distributed in the circumferential direction are used, which preferably form a magnetic ring / magnetic encoder ring, for example with an alternating polarity in the circumferential direction. As a result, continuous reference values can be made available during operation of the electric motor. Similarly, an angular offset can be determined, which can be taken into account in a commutation. It is advantageous that the electrical sensor has a circuit board, wherein on a side facing the rotor of the board a plurality (in particular two, three, four, five or more) digital switch Hall sensors are arranged and / or on one of Rotor remote side of the board a plurality (in particular two, three, four or more) Hall sensors are arranged.

The plane of the board here represents a normal to the axis of rotation of the rotor. The mounted on the board Hall sensors therefore detect the best possible magnetic field of the magnet ring. The board of the sensor assembly has a sensor Endumspritzung, which also serves as a seal against the side of the rotor and the board against the environment fluid-tight manner. Due to the final encapsulation of the electrical sensor, a desired distance to the magnet can also be set (co-).

It is advantageous to provide a Kupplungsausrücksystem with a rotor position sensor assembly. This rotor position sensor assembly requires little space in the clutch release system and precisely measures an angular position. In particular, the rotor position sensor assembly is used in an electrical central release (EZA) of a clutch release system.

In other words, the invention relates to a method for electronically compensating an axial offset of an analog Hall sensor and a corresponding device. In a rotor position sensor system for use in an electronic clutch release system, a distance between an analog Hall sensor and a magnetic ring within a first predetermined range, in particular in a range of about 3.3 mm +/- 1 mm, resulting in a corresponding strength of a Magnetic field within a second predetermined range, in particular in a range of about 22 - 60 mT leads. In order to allow measurement of a rotor position with sufficient accuracy over the entire second predetermined range, an analogue Hall sensor with a variable measuring range is used. More specifically, the variable measuring range has a plurality of measuring stages, wherein adjacent measuring stages overlap each other by a predetermined height.

So it is a solution sought to electronically compensate for a sensor. The invention will be explained in more detail below with reference to preferred embodiments with the aid of figures. Show it:

1 shows a rotor position sensor assembly in an electrical central release

(EZA) of a clutch release system,

2 shows a rotor position sensor assembly for a clutch release system,

FIG. 3 shows a rotor position sensor assembly with final encapsulation of the electrical sensor, FIG.

4 shows a diagram of a magnetic field as a function of the distance from a magnet to the sensor, FIG. 5 shows a table of the sensor with a variable measuring range, and FIG

6 is a diagram illustrating an output signal versus the angle of a rotor position sensor assembly. The figures are schematic in nature and are intended only to aid understanding of the invention. Like elements are provided with the same reference numerals.

1 shows a rotor position sensor assembly 1 according to the invention for a clutch release system 2, which is incorporated in an electrical central release (EZA), with a rotatable relative to a stator 3 rotor 4, wherein the rotor 4 has a magnetic ring 5, in operative contact with the on Stator 3 introduced electrical sensor 6 of the rotor position sensor assembly 1 is.

In contrast to the previously known state of the art, the electrical sensor 6 has a changeable measuring range. A final encapsulation 7 of the sensor made of plastic, such as thermoset, and a sensor seal 8, such as a circumferential rubber seal, serve as a seal and area separation relative to the rotor side of the EZA. On the (EZA) support 9, the stator 3 is arranged circumferentially. Of the Rotor 4 actuates a release system in the axial direction of the rotor 4 via its rotary motion via a ball screw drive. It can be seen from the structure that the sensor assembly 1 can be inserted from the end face of the carrier.

2 shows an illustration of the construction of a rotor position sensor assembly 1 for a clutch release system 2, without Endumspritzung 7 of the electrical sensor 6. One recognizes the curved board 10, on whose top side (or the rotor side facing) three digital switch Hall Sensors 1 1 are applied, as well as on the underside of the board (or the side facing away from the rotor) two analog Hall sensors 12 are. It can be seen in the bent board 10, the bending point of the board 14, whereby these, in particular by substantially 90 °, angled / can be bent. The curved board 10 has a pluggable connection 17, which can be connected / connected to the sensor cable 16 in the sensor carrier 13. On the left and right of the sensor carrier 13 one sees in each case insert bushes for screws 15 with which, as can be seen in FIG. 1, the rotor position sensor assembly 1 can be fastened in the carrier 9.

FIG. 3 shows the rotor position sensor assembly 1 with a final sensor encapsulation 7. The circumferential sensor seal 8, in particular a rubber seal, seals the sensor assembly from the rotor side.

In Fig. 4 shows a diagram of a magnetic field characteristic M. This shows the magnetic field strength as a function of the distance magnet to electric sensor. On the basis of the curve M, which shows the corresponding correlation, the (non-linear) decrease of the magnetic field strength B over the distance A can be clearly seen. Based on a distance, a correspondingly occurring amplitude of the magnetic field can be predetermined. Alternatively, a distance from the sensor to the magnet can also be estimated on the basis of a magnetic field. The present embodiment of the rotor position sensor assembly for a clutch release system has a distance of in particular 3.3 mm with a tolerance of +/- 1 mm. Based on the magnetic field characteristic M of the diagram in FIG. 4, the corresponding magnetic field strength between 22 mT and 60 mT can be read. The measuring range of the sensor can be adjusted according to the magnetic field or according to the distance. Fig. 5 shows a table for a variable-range sensor used in the embodiment. As an electrical sensor, the Hall sensor micronas company called Hal2455 is used. This sensor has six possible settings S1, whereby the measuring range S2 can be varied between +/- 6 mT and +/- 200 mT. The sensor works internally with 16 bit S3, whose high bit S3.1 and low bit S3.2 are selected for processing according to the table. The output in the form of pulse width modulation (PWM) uses 12 bits (PWM) S4. For output, the high bit S4.1 and low bit S4.2 are set accordingly. The resolution can be read in S4.3 and the accuracy in S4.4. In order to ensure the function of the sensor or the requested resolution for all magnet strengths between 20 mT and 60 mT, an overlap of a valid measuring range to the next stage must be greater than 50% under all conditions.

The measured signals are also calibrated in a Digital Signal Process (DSP), whereby a resolution of the angle detection of 0.5 ° is a prerequisite for such a calibration. This means that the number of values A_erf must be at least 512 (9 bits) (A_erf = 8Bit / 0.5el ° = 9Bit). It follows that the amplitude of the signals A_S must be greater than 6.25% of the PWM signal (A_S = 9 bits / 12 bits ^* 100% / 2 = 6.25%). This means that an area of low resolution AU is symmetrical to 50% PWM, with an extension of 6.25% each of the PWM signal, ie a total of 12.5% of the PWM signal.

6 shows a diagram of the PWM signal over the angle Θ, or at a constant angular velocity of the rotor, over the time t. The 50% PWM signal corresponds to the magnetic field strength of B = 0 mT. Symmetrical to the 50% PWM signal, the amplitudes of the evaluated positive and negative (or direction-dependent north-south or south-north of the magnetic field) are magnetic fields, which are converted into a corresponding PWM signal. A signal S, with a correspondingly adjusted measuring range of the sensor, is shown as an example over the angle. One can odic / sinusoidal course over the angle (or at a constant angular velocity over the time t), which oscillates by 50% of the PWM signal. Furthermore, a diagnostic range D can be seen in the range of 90 to 100% PWM or from 0 to 10% PWM.

These two diagnostic areas D are reserved by the manufacturer for diagnostic purposes and can not be used to measure an angular position. Balanced to 50% of the PWM signal, a range extends to low resolution AU. In this range of 12.5% of the PWM signal, the resolution of the angle detection is too poor. If the amplitude of a corresponding PWM signal lies within this range, then the measuring range of the electrical sensor must be changed over to a next measuring range, until the amplitude is above, or below, the too low resolution AU. The valid measuring ranges ME lie between the diagnosis ranges D and the too low resolution AU. These valid measuring ranges ME are to be used for the angle evaluation, i. H. all maxima of the signal should be in the upper green range, while all minima of the signal are in the lower green range. The 50% overlap should be understood as meaning that the sum of all valid ranges should be greater than 40% of the PWM signal. The sum of the valid measuring ranges is equal to 50% less the diagnostic range D.

In the present invention, the following technical influences must be taken into account, which further reduce the valid measuring ranges ME. Approximately proportional to the remanence and independent of the magnetization type and shape of the magnet, the magnetic field changes reversibly with the temperature (about 15%). This reversible change is, to a first approximation, linear and corresponds to a constant increase and decrease per degree Celsius. Furthermore, in the case of rare earth magnets under elevated temperature and in the case of ferrites at low temperature, partial demagnetization may occur (approx. 15%). This leads to a change in the magnetic field when the temperature is first reached. The loss is no longer compensated by the return of the temperature and is therefore irreversible. Furthermore, an offset of the signal may occur due to a mechanical-electrical conversion of the sensor signal (approx. 4%). A tumbling motion of the rotor would also cause signal degradation (about 8%). These technical influences described above This can cause the 40% limit to be exceeded quickly, and the system will provide a worse signal or resolution. To counter this, the following measures should be used. In order to reduce or prevent the reversible or irreversible magnetic loss, a proportion of additional dysprosium (Dy) or cobalt (Co) can be added to the magnetic material (about 5%). Likewise, a pre-aging process can be performed to stabilize the magnetic field (about 10%). A delayed thermal demagnetization follows in the so-called Arrhenius law, ie the progression proceeds logarithmically over the aging time. This means that further changes over days and months only have a very small impact. It is also advantageous if the bearing concept of the rotor is optimized in order to suppress or reduce tumbling (about 4%).

LIST OF REFERENCE NUMBERS

1 sensor module

clutch release

3 stators

rotor

5 magnet ring

6 electrical sensor

7 final sensor injection

8 sensor seal

9 carriers

10 curved board

1 1 Digital Switch Hall Sensor

12 Analog Hall sensor

13 sensor carrier

14 Bend of the board

15 bushings for screws

16 sensor cables

M magnetic field characteristic

S1 setting

S2 measuring range

S3 16-bit (sensor-internal)

S3.1 High bit

S3.2 low bit

S4 12 bit (PWM)

S4.1 High bit

S4.2 Low bit

S4.3 resolution

S4.4 accuracy

ME valid measuring range

D Diagnostic area

AU too low resolution A distance B magnetic field t time

Θ angular position

Claims

claims

1 . Method for measuring the angular position of a rotor (4) relative to a stator (3) for a clutch release system (2) of a motor vehicle, wherein an electrical sensor (6) for detecting at least one magnet (5) present on the rotor (4) is inserted in this way is that the angular position of the rotor (4) to the stator (3) is detected, characterized in that the sensor (6) has different measuring ranges, of which a measuring range targeted to the force acting on the sensor (6) magnetic field (5) becomes.

2. The method according to claim 1, characterized in that such

Measuring range is selected, which covers the magnetic field acting on the sensor (6) to about 100% of its strength or about 140% of its strength.

3. The method of claim 1 or 2, characterized in that the individual selectable and adjacent measuring ranges overlap at least by about 50%

4. The method according to any one of claims 1 to 3, characterized in that as electrical sensor, a Hall sensor (1 1, 12) is used.

5. The method according to any one of claims 1 to 4, characterized in that the measuring range is selected in dependence on the distance of the electrical sensor (6) to the magnet.

6. rotor position sensor assembly (1) for a clutch release system (2), with a relative to a stator (3) rotatable rotor (4), wherein on the stator (3) an electrical sensor (6) is mounted, for detecting by the at least a magnetic field (5) is prepared, characterized in that the electrical sensor (6) has different, selectively selectable measuring ranges, one of which is selected in dependence on the magnetic field acting on the sensor.

Rotor position sensor assembly (1) according to claim 6, characterized in that the electrical sensor (6) from a front side of a carrier (9) on which the stator (3) is fixed, engages in or engages in order to be in operative contact with the at least one magnet (5) to arrive and the rotor (4) from a opposite end face of the support (9) is arranged statornah and close to the sensor.

Rotor position sensor assembly (1) according to claim 6 or 7, characterized in that a plurality of circumferentially distributed magnets (5) are used.

Rotor position sensor assembly (1) according to one of claims 6 to 8, characterized in that the electrical sensor (6) has a circuit board (10), wherein on a rotor (4) facing side of the board (10) has a plurality of digital switch Hall sensors (1 1) is arranged and / or on a side facing away from the rotor (4) of the board (10) a plurality of analog Hall sensors (12) is arranged. Coupling release system (2) with a rotor position sensor assembly (1) according to one of claims 6 to 8.