Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
  • G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
  • G01D5/2451—Incremental encoders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D15/00—Steering not otherwise provided for
  • B62D15/02—Steering position indicators ; Steering position determination; Steering aids
  • B62D15/021—Determination of steering angle
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D2205/00—Indexing scheme relating to details of means for transferring or converting the output of a sensing member
  • G01D2205/80—Manufacturing details of magnetic targets for magnetic encoders

Definitions

• the invention relates to a method for detecting an angular position of a shaft of a motor vehicle when the ignition is switched off and to a sensor arrangement for detecting an angular position of a shaft of a motor vehicle with the ignition switched off.
• Rotatable shafts are used in different devices, for example.
• a rotation angle sensor or a torque sensor In this case, a relative rotation of two shafts relative to one another can be detected with a torque sensor.
• torque sensors a magnetic method is typically used, as described, for example, in the document DE 10 2005 031 086 A1. In this case, a magnetic field of a magnetic multipole, which is arranged on a shaft, measured. With a so-called True Power On function (TPO), the angular position of a steering wheel of a motor vehicle when switching on the ignition can be determined by sensors.
• TPO True Power On function
• a gear transmission is needed, which translates the rotational movements, so that after the Switching on the ignition can be calculated based on the translation a clear signal.
• two gears can be used with unequal numbers of teeth, with their teeth engage in teeth of a gear which is arranged on a hub of a shaft.
• a hypercycloidal transmission can also be used, as described, for example, in the document DE 10 2008 01 1 448 A1.
• the steering angle of a steering column can be calculated from the position of a rotor position sensor used in power steering systems (EPS) and detects the rotation of the steering column via the reduction of an EPS motor used in the power steering.
• EPS power steering systems
• a magnet unit which comprises a multipole wheel of circular or annularly arranged magnets.
• Field lines of a magnetic field of a magnet are oriented according to the definition of the north pole to the south pole of the magnet or vice versa.
• the field lines of immediately adjacent magnets are oppositely oriented.
• the at least one magnetic field-sensitive sensor element measures and detects the magnetic field of the multipole wheel, which results from superposition of the magnetic fields of all the magnets of the multipole wheel. From the position of the magnetic field, furthermore, the position of the multipole wheel and thus the angular position of the shaft, for example by calculation, can be derived and / or determined. In an embodiment of the invention can be detected by the rotation of the shaft change of the magnetic field at a position at which the at least one magnetic field-sensitive sensor element is arranged, of the at least one magnetic field-sensitive sensor element with the ignition off.
• the change in the angular position can thus be registered quickly and reliably, so that a wake-up function is activated by the at least one magnetic-field-sensitive sensor element, thereby signaling the change with the ignition switched off to a control device, for example for a steering system comprising the shaft.
• the resulting prompt changes and thus reorientations and / or rotations of the field lines of the moving magnetic field can be counted incrementally. From this, it can be determined from the number of resulting changes of the magnetic field, which result from passing interfaces, by how many degrees the angular position of the shaft has changed during one rotation. Starting from a previous angular position, taking into account the rotation, it is possible to reconstruct which angular position the shaft currently has.
• this circuit can be arranged in the at least one magnetic field-sensitive sensor element or in a control unit as a component of the sensor arrangement.
• the circuit and / or the at least one magnetic field-sensitive sensor element may comprise the magnetic-field-sensitive switch, which registers a usually spatial change in the magnetic field of the multipole wheel and reacts thereto by activating the wake-up function.
• a change in the magnetic field can cause a position of the magnetic-field-sensitive switch to be changed and a circuit to be closed, which in turn activates the wake-up function.
• the values acquired for at least one angular position and / or at least one rotation can also be stored in the circuit, which is embodied, for example, as an application-specific integrated circuit (ASIC) and used when the ignition is switched on.
• ASIC application-specific integrated circuit
• a non-contact rotational angle and / or torque sensor with a wake-up function is provided by the invention. It is possible, even a multiple complete revolution of the shaft, d. H. by more than 360 °, to capture and thus realize a so-called multi-turn function.
• the at least one magnetic field-sensitive sensor element may include, as possible components in addition to the magnetic field-sensitive switch, an AMR element for measuring an anisotropic magnetoresistance, a GMR element for measuring the giant magnetoresistor, or a Hall element.
• an orientation of the field lines of the magnetic field of the multipole wheel oriented largely radially to the axis of rotation of the shaft is determined.
• the position of the multipole wheel can also be calculated on the basis of the field strength of the magnetic field.
• the angle of the interface between two magnets and thus within a pole region, which is arranged between two adjacent magnets net is to be determined very precisely.
• Rotation of the multipole wheel relative to the at least one magnetic field sensitive sensor element and thus the magnetic field sensitive switch from a first pole region to an adjacent next pole region disposed between the two nearest magnets is due to the change in direction of the field lines with the magnetic field sensitive switch good to determine.
• a movement of the magnets relative to the at least one magnetic field-sensitive sensor element caused by rotation or further rotation and a change in the magnetic field resulting therefrom are detected and configured in a memory configured as an EEPROM which is designed as a component of the at least one magnetic field-sensitive sensor element and / or the control device can, saved.
• At least one stored value for the change of the magnetic field and / or the angular position can be further processed by the at least one magnetic-field-sensitive sensor element or the control device, whereby it is usually determined how large the angle through which the shaft rotates during the performed rotation Has.
• This at least one stored value can be available to the control unit at a start of the motor vehicle by activation of the ignition.
• the at least one magnetic field-sensitive sensor element which comprises the ASIC-designed circuit, for example, in which the wake-up function for waking up the control unit is implemented via the magnetic-field-sensitive switch, is supplied with electrical energy by the control unit.
• the ignition is switched off, a low quiescent current is provided to the at least one magnetic field-sensitive sensor element by the control unit.
• the at least one magnetic field-sensitive sensor element can be configured to detect a rotation of the shaft even when the ignition is switched on, wherein the control unit provides a current or alternating current which is generally constant and whose magnitude can be greater than that of the quiescent current to the at least one magnetic field-sensitive sensor element ,
• a period p at which the angular position of the shaft is interrogated is chosen so that movement of the shaft, usually the steering shaft, can be reliably detected when the ignition is off, but due to the mechanical inertia of the shaft as long as possible resting phase between two periods of the quiescent current is present.
• the idle phase reduces power consumption when the ignition is off.
• the at least one magnetic field-sensitive sensor element which comprises the switch designed as a reed switch, is also supplied with energy when the ignition is switched off. If the magnetic field of the multipole wheel changes, the magnetic field-sensitive switch is switched and the wake-up function is activated. Alternatively or additionally, the change in the magnetic field registered as a result of the change in the movement can be stored in the memory of the magnetic-field-sensitive sensor element. Due to the change in the magnetic field, it is also possible to determine and store a resulting change in the angular position.
• At least one such determined and stored angular position can be interrogated within the fixed period p and compared with at least one value of the previous period, wherein a comparison and optionally a storage of at least one of the values of the sensor element and / or the control unit can be made.
• the magnetic-field-sensitive switch is then switched and thus activated if a value of the magnetic field changes by a defined minimum amount, which depends on a sensitivity of the magnetic-field-sensitive switch.
• the at least one magnetic field-sensitive sensor element comprising the magnetic field-sensitive switch can detect the further rotation of the shaft, activate the wake-up function and send a signal to the control unit, wherein the
• Control unit of the signal which may also include a detected value of the magnetic field and / or the angular position is awakened.
• the at least one magnetic field-sensitive sensor element can automatically store information about a rotational movement in the memory.
• the control unit which is designed to control, ie to control and / or regulate or monitor a function of the shaft, immediately upon switching on the ignition, the current angular position of the shaft and thus a steering wheel, which may be connected to the shaft ready. be put.
• the wake-up function implemented in the at least one magnetic-field-sensitive sensor element upon detection of rotation of the shaft which can be designed as an EPS rotor
• a function for controlling the shaft can be awakened for the control device when the ignition is switched off by a signal from the at least one magnetic field-sensitive sensor element and thus activated.
• the at least one magnetic field-sensitive sensor element can be interrogated by the control unit alternatively or additionally in regular periods p, wherein a rotational movement of the shaft is recorded and stored, so that the current angular or rotational position after switching on the ignition is available.
• the sensor arrangement according to the invention is designed to carry out all the steps of the presented method.
• individual steps of this method can also be carried out by individual components of the sensor arrangement.
• functions of the sensor arrangement or functions of individual components of the sensor arrangement can be implemented as steps of the method.
• steps of the method it is possible for steps of the method to be realized as functions of at least one component of the sensor arrangement or of the entire sensor arrangement.
• Figure 1 shows an embodiment of a sensor arrangement according to the invention from a first perspective in a schematic representation.
• FIG. 2 shows components of the sensor arrangement according to the invention from FIG. 1 from a second perspective in a schematic representation.
• FIG. 1 shows components of the sensor arrangement 2 according to the invention and of the steering system 4 from a direction which is oriented axially relative to the axis of rotation 6.
• the steering system 4 comprises a first shaft 8 and a second shaft 10, which can rotate here about the common axis of rotation 6 and are connected to each other via a torsion bar 12.
• the first shaft 8 comprises a magnet unit 14 which has a multipole wheel 16 arranged on the first shaft 8.
• This Multipolrad 16 includes a plurality of ring and / or ring-shaped magnets arranged 18, 20.
• Pol Suitee of first magnet 18 from the axis of rotation 6 outward in north-south direction and Pol Schemee of second magnet 20, the the first magnet 18 are immediately adjacent, oriented from the axis of rotation 6 outward in the south-north direction.
• the multipole wheel 16 alternately adjacent to each other adjacent first and second magnets 18, 20 which comprise mutually oppositely oriented magnetic fields.
• Field lines 22 of a common magnetic field which is formed by superposition of the magnetic fields of the individual magnets 18, 20, are also indicated in FIGS. 1 and 2.
• the sensor arrangement 2 comprises a first magnetic-field-sensitive sensor element 24, which is arranged on a first printed circuit board 26 and has an ASIC as a circuit. It is provided that the first magnetic field-sensitive Sensor element 24 and thus the ASIC is arranged parallel to the multipole 16 of the magnet unit 24.
• Magnetic field of the multipole 16 which changes between two adjacent magnets 18, 20 by 180 °, are detected quantitatively and / or qualitatively.
• a second magnetic field-sensitive sensor element 28 is assigned to the second shaft 10 and arranged on a second printed circuit board 30, on which furthermore a
• the second magnetic field-sensitive sensor element 28 is formed as a component of a so-called sensor unit 34 of a torque sensor, with which a relative rotation of the two shafts 8, 10 about the common axis of rotation 6 is detected. In this case, a twisting of the torsion bar 12 between the two shafts 8, 10 is caused by a torque.
• the magnetic field of the multipole wheel 16 is amplified by a magnetic flux unit 36, which is arranged on the second shaft 10 and formed of ferromagnetic material, so that the magnetic field can also be detected by the second magnetic field-sensitive sensor element 28.
• the sensor arrangement 2 shown here also has a control unit 38, which is connected via a connecting line 40 to the magnetic field-sensitive sensor elements 24, 28, here via the printed circuit boards 26, 30.
• the connecting line 40 may be formed as a cable, semi-flexible printed circuit board, etc.
• a connection between the two circuit boards 26, 30 is not necessarily necessary, but leads to a cost-effective design, since only one connection to the control unit 38 is required.
• the first magnetic field-sensitive sensor element 24 can be connected via the plug 32 on the second printed circuit board 30 or directly to the control unit 38 (connecting line 40 shown in dashed lines).
• At least one of the two magnetic-field-sensitive sensor elements 24, 28 has a magnetic-field-sensitive switch designed here as a reed switch 50, which wakes the sensor arrangement 2 when the generated magnetic field 22 changes.
• a change in the angular position of at least one shaft 8, 10 in a movement of the multipole 16, by the here spatial change of the magnetic field is registered.
• a qualitative detection of the magnetic field usually the change of the magnetic field, is detected and / or registered at least by the magnetic-field-sensitive switch.
• Quantitative changes in the magnetic field can also be determined by a further component of a magnetic-field-sensitive sensor element 24, 28, which may be designed as a GMR, AMR or Hall element.
• the multipole wheel 16 of the magnet unit 14 is configured to provide a signal of a measured steering angle as the angular position of the first shaft 8 and to provide a signal of measured torque between both shafts 8, 10.
• both functions can be integrated in a sensor arrangement 2.
• a multipole wheel to be arranged on the second shaft 10, whose rotating magnetic field is detected by the second magnetic field-sensitive sensor element 28. From the difference of the angular positions of both shafts 8, 10, the torque and / or a relative angle between the two shafts 8, 10 can be determined within the scope of the invention even when the ignition is switched off.
• the sensor arrangement 2 which has at least one magnetic field-sensitive sensor element 24, 28, for detecting an angular position of at least one shaft 8, 10 of a motor vehicle with the ignition switched off.
• a multipole wheel 16 made of magnets 18, 20 is arranged on the at least one shaft 8, 10.
• the at least one magnetic field-sensitive sensor element 24, 28 detects a magnetic field generated by the magnets 18, 20 and thus the multipole 16.
• an orientation or orientation of the field lines 22 of the magnetic field and / or a field strength of the magnetic field as parameters of the magnetic field can be detected qualitatively and / or quantitatively.
• At least one parameter of the magnetic field is interrogated periodically via a quiescent current, and values of at least one magnetic field-sensitive sensor element 24 are detected by the at least one parameter and, if necessary, processed.
• This may mean that a value of the magnetic field, which is detected at a first, for example, previous, period, with a value of the magnetic field at a second, for example, current, period, which is usually directly after the first period, is detected is compared.
• a change in the angular position upon rotation of the at least one shaft 8 causes a change in the magnetic field generated by the Multipolrad 50, which is registered by the magnetic field-sensitive switch and / or relay designed here as a reed switch 50.
• the change can be stored in a memory of the at least one magnetic field-sensitive sensor element 24 and / or the control device 38 configured as an EEPROM.
• a wake-up function implemented in a circuit of the at least one magnetic-field-sensitive sensor element 24 can be activated via the reed switch 50 and the control device 38 thereby awakened.
• a transition usually an interface between two adjacent magnets 18, 20 detected. If the transition between two adjacent magnets 18, 20 moves past the magnetic-field-sensitive switch 50 and thus passes by it, a circuit is closed via the magnetic-field-sensitive switch 50 and the wake-up function is also activated. Accordingly, the at least one magnetic field-sensitive sensor element 24 with the magnetic field-sensitive switch 50 comprises an event-triggered circuit.
• a registered event is usually a minimum movement of the multipole wheel 16, which causes a spatial change of the magnetic field at the position of the magnetic-field-sensitive switch 50. In this case, a movement of the magnets 18, 20 relative to the at least one magnetic field-sensitive sensor element 24 can be counted incrementally.
• the at least one magnetic field-sensitive sensor element 24 and thus the reed switch 50 of the sensor arrangement 2 are supplied with a normally periodic quiescent current when the ignition is switched off, which is provided, for example, by the control unit 38.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Priority Applications (2)

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Publications (1)

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ID=45888209

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Citations (5)

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• 2011
  • 2011-04-08 DE DE102011007023A patent/DE102011007023A1/de not_active Withdrawn
• 2012
  • 2012-03-21 CN CN201280016677.3A patent/CN103443591B/zh active Active
  • 2012-03-21 EP EP12710716.7A patent/EP2694922A1/de not_active Withdrawn
  • 2012-03-21 WO PCT/EP2012/055027 patent/WO2012136481A1/de active Application Filing

Patent Citations (5)

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