Surveying device

Abstract

Device (1) for non-invasive measurement of the position of Hall sensors installed in a component (9), comprising - a positioning device (3) for the fixable mounting of the component (9) with at least one sensor (2) to be measured, - a rotary encoder wheel (5) mounted about an axis (4) for generating a temporally and spatially defined magnetic test signal and - at least one reference sensor (6) for determining a reference position of the encoder wheel (5), - wherein at least one magnet (27) with a predetermined polarity is arranged on the encoder wheel (5) to generate the test signal, and wherein the component (9) is fixed in a predetermined position in the device (1) by means of a reference mounting surface (14) and / or a reference pin (15).

Description

[0001] The invention relates to a device and a method for the non-invasive measurement of Hall sensors in the installed state.

[0002] Hall effect sensors are used in the automotive industry, for example, for speed measurement, direction detection, shift detection, and position measurement. For this purpose, the sensors are typically installed in so-called sensor pockets within the housing of a component, making them inaccessible from the outside. Once installed, the position of the sensors can no longer be determined tactilely or optically. Determining the sensor's position usually requires destroying the component's housing.

[0003] German patent DE 100 41 096 A1 discloses a method for the computational correction of angle measurements using at least two code tracks, which allows, in particular, the subsequent correction of assembly and manufacturing errors. Such errors lead to eccentricities, pole pitch errors, and mismatches, and can be eliminated retrospectively. During initial calibration, the errors of the input variables or signals derived therefrom are determined and stored using a reference angle encoder. The errors are filtered using Fourier analysis. During operation, the filtered errors are subtracted from the measured angle values ​​as a function of the rotation angle. This correction can be repeated iteratively until the error angle is minimized. The method can be used for determining the steering angle and / or torsion angle of a motor vehicle.

[0004] From DE 100 54 530 A1, a method for determining the angular position of a rotatable shaft is known. The angular position of the shaft, for example, the position of the shaft of a brushless motor, can be determined using sensors designed as Hall sensors and a sensor arrangement that moves with the shaft and has several magnetic poles as encoders. The change in the magnetic field of the encoder arrangement resulting from the rotation of the shaft is detected by the sensors and evaluated to determine the angular position of the shaft. For the method, a reference measurement is first performed in which the angular distances corresponding to the actual sensor positions and the actual widths of the encoders are calculated from the sensor signals emitted by the sensors. From these angular distances, the angular position of the shaft is then determined at specific times.

[0005] It is therefore an object of the invention to provide a device and a method for improved measurement of Hall sensors in the installed state.

[0006] This problem is solved by the features of claim 1 and claim 11.

[0007] The core of the invention consists of generating a temporally and spatially defined magnetic test signal for the non-invasive measurement of Hall sensors in their installed state and determining the position of the sensor to be measured from the corresponding sensor signal registered by the sensor. An arrangement of magnets on a sensor wheel is provided for generating the test signal.

[0008] Advantageously, the measuring device includes a positioning device which enables precise, reproducible alignment of the component with the sensor to be measured.

[0009] For measuring Hall sensors, a sensor wheel with circumferentially arranged magnets is preferably provided to generate the temporally and spatially defined test signal. A test signal with a specific field profile can be achieved through the arrangement and orientation of the magnets.

[0010] It is advantageously provided that the magnets are arranged along one or more magnetic tracks on the encoder wheel. With such an arrangement, several sensors offset from each other in the axial direction can be measured particularly efficiently.

[0011] A drive unit and an angle encoder facilitate the use of the device and, in particular, the evaluation of the signals registered by the sensor.

[0012] To measure a Hall sensor, it is advisable to apply an operating voltage to it.

[0013] Advantageously, the test signal has a minimum amplitude to reach the switching points of the sensor being measured.

[0014] A field profile with a steep gradient increases the accuracy of position determination.

[0015] Further advantages, details, and features of the invention will become apparent from the description of an exemplary embodiment with reference to the drawings. These show: Fig. 1 a view of a surveying device according to a first embodiment of the invention, Fig. 2 a top view of a encoder wheel with three magnets forming a magnetic track, Fig. 3 a side view of the encoder wheel according to Fig. 2 with the magnets arranged adjacent in the circumferential direction, Fig. 4 a representation of the sensor wheel according to the Fig. 2 and Fig. 3. Field pattern generated at the location of the Hall sensors to be measured as a function of the angular position of the encoder wheel, Fig. 5 a view of a component with sensors to be measured and Fig. 6 a sectional view along line VI-VI through the component according to Fig. 5.

[0016] A device 1 for non-invasive measurement of sensors 2, in particular Hall sensors, comprises a positioning device 3, a encoder wheel 5 rotatably mounted about an axis 4 and a reference sensor 6.

[0017] Furthermore, a drive motor 7 is provided for driving the encoder wheel 5. The drive motor 7 is equipped with an angle encoder 8.

[0018] The positioning device 3 serves to securely hold a component 9 in which at least one sensor 2 to be measured is installed. The positioning device 3 is adapted to the component 9 with the sensor 2 to be measured. For this purpose, it has an insertion pin 11 that is slidably mounted on a first slide 10 in the direction of the axis 4. The insertion pin 11 has a cylindrical circumference, the dimensions of which are adapted to those of a circular receptacle 12 in a housing 13 of the component 9. The component 9 can thus be placed onto the insertion pin 11 and, in the placed state, can be moved in the direction of the axis 4 by means of the first slide 10. To ensure secure fixation and reproducible positioning of the component 9 in the device 1, a reference contact surface 14 with a reference pin 15 is provided.With the aid of the reference mounting surface 14, which interacts with a corresponding mounting projection 16 on the housing 13 of component 9, a reproducible displacement position of component 9 mounted on the first slide 10 in the direction of axis 4 can be ensured. Similarly, the angular position of component 9 with respect to axis 4 can be reproducibly adjusted by means of the reference pin 15, which interacts with a reference bore 17 in the housing 13 of component 9.While the component 9, in the state mounted on the insertion pin 11 without engaging the reference pin 15 with the reference bore 17 and / or the reference contact surface 14 with the contact projection 16, has both a rotational and a translational degree of freedom, the position of the component 9 in the device 1 can be uniquely and reproducibly determined by engaging the reference pin 15 with the reference bore 17 and / or the reference contact surface 14 with the contact projection 16.

[0019] The first slide 10 with the insertion pin 11 and the reference mounting surface 14 with the reference pin 15 are components of the positioning device 3.

[0020] Extending from the insertion pin 11, a drive shaft 18 is arranged, which can be rotated about the axis 4 by the drive motor 7. The drive shaft 18 can be inserted into a corresponding drive receptacle 19 in the encoder wheel 5 by sliding the first slide 10. In the inserted state, the drive shaft 18 is connected to the encoder wheel 5 in a torque-transmitting manner. For this purpose, the drive shaft 18 preferably has a non-circular cross-section, for example, an oval, preferably a star-shaped or polygonal cross-section. The drive shaft 18 can also have a circular cross-section. The cross-section of the drive receptacle 19 is adapted to that of the drive shaft 18. The drive shaft 18 is positively engaged with the encoder wheel 5. However, a friction-fit engagement of the drive shaft 18 in the drive receptacle 19 is also conceivable.

[0021] To stabilize the positioning device 3, a second slide 20, also slidably mounted in the direction of the axis 4 and equipped with an engagement pin 21, is provided on the side opposite the drive motor 7 with respect to the encoder wheel 5. By moving the second slide 20 in the direction of the axis 4, the engagement pin 21 can be inserted into the drive receiving opening 19 in the encoder wheel 5. The engagement pin 21 is preferably able to engage with the drive shaft 18. Thus, the component 9 can be mounted on both sides of the encoder wheel 5 in the direction of the axis 4 by means of the positioning device 3. This mounting on both sides allows the component 9 to be mounted particularly securely and precisely in the positioning device 3. In particular, imbalances and tolerances resulting from pivoting of the component 9 out of a plane perpendicular to the axis 4 are avoided.

[0022] The encoder wheel 5 is connected to a base plate 23 of the device 1 by means of a bracket 22. It is rotatably mounted in the bracket 22 about the axis 4. The reference sensor 6 is also arranged on the bracket 22. The reference sensor 6 thus has a fixed, known spatial relationship to the encoder wheel 5. It can be advantageous to arrange the reference sensor 6 adjustably on the bracket 22. The reference sensor 6 serves to determine a reference position of the encoder wheel 5, from which its angular positions can be measured, in particular with the aid of the angle encoder 8. The reference sensor 6 is connected to a control unit 24 in a data-transmitting manner. The control unit 24 is also connected to the angle encoder 8 in a data-transmitting manner.

[0023] Furthermore, contact elements 25 are provided with the control unit 24 for data transmission. When the component 9 is installed, these contact elements 25 are in contact, specifically electrical connection, with a terminal contact 26 of the component 9. The terminal contact 26 of the component 9 is in data transmission communication with the sensors 2. Thus, the sensor signals registered by the sensors 2 can be received and evaluated by the control unit 24.

[0024] Several magnets 27 are arranged on the encoder wheel 5. The magnets 27 are permanent magnets. Magnets 27 made of samarium-cobalt alloys, especially SmCo5, have proven particularly advantageous. Such alloys allow for a particularly high energy density. The maximum energy density of the magnets 27 is at least 100 kJ / m³. 3 , preferably at least 130 kJ / m² 3Furthermore, such alloys exhibit a low absolute temperature coefficient of the remanent flux density. For magnets 27, this temperature coefficient is approximately -0.045% / K. The absolute value of the temperature coefficient is particularly less than 0.1% / K, preferably less than 0.05% / K. A further advantage of magnets 27 is that irreversible magnetic losses up to a temperature of 150 °C amount to a maximum of 5%, particularly 3%, and particularly 1%.

[0025] Advantageously, the magnets 27 are integrated into the encoder wheel 5, i.e., embedded within it. They do not protrude radially beyond the circumference of the encoder wheel 5 and are preferably flush with it. It is provided that several magnets 27 are arranged adjacent to one another in the circumferential direction. At least two of the circumferentially adjacent magnets 27 have opposite polarities. By arranging two adjacent magnets 27 with opposite polarities, a steep spatial profile, i.e., a steep gradient of the resulting magnetic field, can be achieved. The magnetic test signal generated by the encoder wheel 5 preferably has a maximum slope of at least 3 mT / degree, in particular at least 5 mT / degree, and in particular at least 10 mT / degree.

[0026] The remanence of the magnets 27 is at least 0.5 T, in particular at least 0.7 T, preferably at least 0.85 T.

[0027] The magnets 27 are arranged with a uniform orientation in the axial direction of the encoder wheel 5 and thus form a magnetic track. In a particularly advantageous embodiment, several spaced-apart, parallel magnetic tracks are provided on the encoder wheel 5. This allows several sensors 2 to be measured in a particularly efficient manner. Furthermore, with such an embodiment, the position of the sensors 2 in the direction of the axis 4 can also be determined.

[0028] To measure the sensors 2 integrated into component 9, component 9 is fixed in the device 1 using the positioning device 3. For this purpose, it is placed onto the insertion pin 11 on the first slide 10 using the receptacle 12. The first slide 10 is then moved in the direction of the axis 4, thereby inserting the drive shaft 18 into the drive receptacle opening 19 of the encoder wheel 5. Component 9 is fixed in a predetermined position in the device 1 using the reference contact surface 14 and / or the reference pin 15. Furthermore, the positioning device 3 is stabilized by inserting the second slide 20, in particular by engaging the engagement pin 21 with the drive shaft 18. When inserted into the positioning device 3, the connection contact 26 of component 9 is in electrical contact with the contact elements 25 of the device 1.

[0029] The encoder wheel 5 is then rotated around the axis 4 by means of the drive motor 7. A reference position of the encoder wheel 5 is determined using the reference sensor 6. From the reference position and the signal from the angle encoder 8, the angular position of the encoder wheel 5 can be uniquely determined by the control unit 24. The accuracy is better than 5°, in particular better than 1°, preferably better than 0.05°. It preferably has a resolution of at least 12 bits, in particular at least 13 bits.

[0030] As the encoder wheel 5 continues to rotate about the axis 4, the magnets 27 are guided past the sensors 2 to be measured. The temporally and spatially defined magnetic test signal generated by the encoder wheel 5 is received by the sensors 2 as a measurement signal and transmitted to the control unit 24.

[0031] The position of each sensor 2 is determined by the control unit 24 based on the relationship between the measurement signal registered by each sensor 2 and the angular position of the encoder wheel 5. This only requires determining the relative angular position of the installed sensor 2 to the reference sensor 6. Measuring the position of sensor 2 is therefore very simple. Furthermore, by evaluating the measurement signal as a function of different magnetic traces, the position of sensor 2 in the direction of axis 4 can be determined.

[0032] The measurement signal can be acquired using a windowed approach. This allows the number of magnets 27 per magnetic track to be reduced. In a preferred embodiment, each magnetic track has only three magnets 27 with alternating polarity.

[0033] The selection and arrangement of the magnets 27 ensures that the switching thresholds of the sensors 2 are reached when the encoder wheel 5 is rotated, i.e. when the magnets 27 pass by the sensors 2.

[0034] To measure the sensors 2, several successive switching operations are advantageously recorded. According to the invention, at least 10, in particular at least 30, preferably at least 50 successive switching operations of the sensors 2 are to be recorded.

[0035] To measure the sensors 2, an operating voltage U is used. H applied to these. The operating voltage U H The operating voltage U can be preset using the control unit 24, depending on the sensors 2. This prevents incorrect settings by the user. H The voltage range is from 100 mV to 24 V.

[0036] The magnetic test signal generated by the encoder wheel 5 in the area of ​​the sensor 2 to be measured has a maximum value of at least 2 mT, in particular at least 2.5 mT, and in particular at least 3 mT. This ensures that the switching points of the sensor 2 are reached. The exact value of the magnetic test signal generated by the encoder wheel 5 may also deviate from the specified values, depending on the requirements of the sensor 2 to be measured.

Claims

[1] Device (1) for non-invasive measurement of the position of Hall sensors installed in a component (9), comprising - a positioning device (3) for the fixable mounting of the component (9) with at least one sensor (2) to be measured, - a rotary encoder wheel (5) mounted about an axis (4) for generating a temporally and spatially defined magnetic test signal and - at least one reference sensor (6) for determining a reference position of the encoder wheel (5), - wherein at least one magnet (27) with a predetermined polarity is arranged on the encoder wheel (5) to generate the test signal, and wherein the component (9) is fixed in a predetermined position in the device (1) by means of a reference mounting surface (14) and / or a reference pin (15). [2] Device (1) according to claim 1, characterized bythat the positioning device (3) is adapted to the component (9) with the at least one sensor (2) to be measured. [3] Device (1) Device according to any of the preceding claims, characterized by , that the at least one magnet (27) is arranged circumferentially on the encoder wheel (5). [4] Device (1) according to any one of the preceding claims, characterized by that several magnets (27) are arranged adjacent to each other in the circumferential direction on the encoder wheel (5). [5] Device (1) according to claim 4, characterized by , that at least two of the circumferentially adjacent magnets (27) have different polarities. [6] Device (1) according to claim 4 or 5, characterized by , that the magnets (27) form at least one magnetic track with a uniform orientation in the axial direction of the encoder wheel (5). [7] Device (1) according to claim 6, characterized by, that several spaced-apart, parallel magnetic tracks are provided on the encoder wheel (5). [8] Device (1) according to any one of the preceding claims, characterized by , that a drive device (7) is provided for driving the encoder wheel (5). [9] Device (1) according to any one of the preceding claims, characterized by , that an angle encoder (8) is provided for the temporally resolved detection of the angular position of the encoder wheel (5). [10] Device (1) according to claim 9, characterized by , that the angle encoder (8) is integrated into the drive unit (7). [11] Method for non-invasive measurement of the position of Hall sensors installed in a component (9) comprising the following steps: - Fixing the component (9) in a predetermined position using a reference mounting surface (14) and / or a reference pin (15), - Providing a rotary encoder wheel (5) mounted about an axis (4) for generating a temporally and spatially defined magnetic test signal, - Rotating the encoder wheel (5) about the axis (4) to generate a reference signal in a reference sensor (6) and a measurement signal in a sensor (2) to be measured, - Determining a reference position of the encoder wheel (5) using the reference sensor (6), - Recording the measurement signal using the sensor (2) to be measured, wherein the sensor (2) is installed in the component (9), - Determining the position of the sensor (2) to be measured in the component (9) from the dependence of the measurement signal registered by the sensor (2) on the angular position of the encoder wheel (5). [12] Method according to claim 11, characterized by , that a voltage (U) is required to measure the sensor (2) H ) is attached to these. [13] Method according to one of claims 11 or 12, characterized by, that the magnetic test signal generated by the encoder wheel (5) in the area of ​​the sensor (2) to be measured has a maximum value of at least 2 mT, in particular at least 2.5 mT, in particular at least 3 mT. [14] Method according to any one of claims 11 to 13, characterized by , that the magnetic test signal generated by the encoder wheel (5) has a maximum slope of at least 5 mT / °, in particular at least 10 mT / °.

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