阅读说明：本技术 转子位置传感器和带有转子位置传感器的机动车辆转向系统 (Rotor position sensor and motor vehicle steering system with a rotor position sensor ) 是由 塔马斯·费耶什 罗兰·盖迈希 阿贝尔·维尔 于 2020-05-11 设计创作，主要内容包括：本发明涉及一种转子位置传感器(10),用于确定电动机转子轴的角位置,其具有可以在端部固定到转子轴的发射器元件(11),该发射器元件具有至少一个居中布置的发射器磁体(12),并且具有至少一个可在电机轴的延伸上在电路载体(13)上与该发射器磁体(12)相对定位的磁场传感器,其形成用于输出根据发射器元件(11)的角位置的第一传感器信号,其中在该发射器元件(11)上设置至少一个在围绕发射器磁体(12)的周向上限定出的导电区域(15),用于与设置在电路载体(13)上的线圈系统(16)感应式共同作用,以根据发射器元件(11)的角位置生成第二传感器信号,此外本发明涉及用于机动车辆的转向系统,其具有根据发明的转子位置传感器(10)。(The invention relates to a rotor position sensor (10) for determining the angular position of a rotor shaft of an electric motor, having a transmitter element (11) which can be fixed at the end to the rotor shaft and which has at least one centrally arranged transmitter magnet (12) and at least one magnetic field sensor which can be positioned opposite the transmitter magnet (12) on a circuit carrier (13) over the extension of the motor shaft and which forms a first sensor signal for outputting a signal as a function of the angular position of the transmitter element (11), wherein at least one electrically conductive region (15) which is delimited in the circumferential direction around the transmitter magnet (12) is provided on the transmitter element (11) for inductively interacting with a coil system (16) which is provided on the circuit carrier (13) in order to generate a second sensor signal as a function of the angular position of the transmitter element (11), the invention further relates to a steering system for a motor vehicle, comprising a rotor position sensor (10) according to the invention.)

1. A rotor position sensor for determining an angular position of a rotor shaft of an electric motor (7), the rotor position sensor having: a transmitter element (11) which can be fixed at the end to the rotor shaft and which has at least one centrally arranged transmitter magnet (12); and having at least one magnetic field sensor which can be positioned opposite the transmitter magnet (12) on the circuit carrier (13) over the extension of the motor shaft and which forms a sensor signal for outputting a first sensor signal as a function of the angular position of the transmitter element (11), characterized in that at least one electrically conductive region (15) which is delimited in the circumferential direction around the transmitter magnet (12) is provided on the transmitter element (11) for inductively interacting with a coil system (16) provided on the circuit carrier (13) in order to generate a second sensor signal as a function of the angular position of the transmitter element (11).

2. A rotor position sensor according to claim 1, characterised in that the rotor position sensor (1) comprises an analysing unit (20) for analysing the first and second sensor signals, which analysing unit is formed for performing a disturbance field detection and, if one of the sensor signals deviates from an expected signal curve, providing the respective other sensor signal at an output of the analysing unit (20).

3. A rotor position sensor according to claim 1 or 2, characterized in that at least two electrically conductive areas (15) are provided which are spaced apart from one another in the circumferential direction, and that the coil system (16) and the magnetic field sensor (14) each have at least twice the redundancy for generating at least two first sensor signals and two second sensor signals.

4. A rotor position sensor according to any of claims 1-3, characterized in that the coil system (16) comprises at least one transmitting coil (17) for generating an alternating field and at least one receiving coil (18) for detecting an alternating field locally influenced by at least one electrically conductive area (15) of the transmitter element (11).

5. A rotor position sensor according to claim 4, characterised in that the coil system (16) has a number of receiving coils (18) corresponding to the number of conductive areas (15) of the transmitter element (11).

6. Rotor position sensor according to claim 4 or 5, characterized in that at least two receiving coils (18) are arranged on the circuit carrier (13) in a rotationally symmetrical fashion.

7. A rotor position sensor according to any one of claims 4 to 6, characterised in that the transmitter coil (17) is formed so as to be centrosymmetric around the magnetic field sensor (14).

8. A rotor position sensor according to any one of claims 4 to 7, characterised in that the receiving coil (18) has at least one turn (19) which surrounds the magnetic field sensor (14) eccentrically.

9. A rotor position sensor according to any of claims 1-8, characterized in that the second sensor signal is generated by detecting the inductance of the coils (17, 18) of the coil system (16) which depends on the angular position of the transmitter element (11).

10. A rotor position sensor according to any of claims 1 to 8, characterised in that the conductive area (15) is made of a soft magnetic material.

11. A steering system for a motor vehicle, the steering system comprising: a steering handle (3) for inputting a steering request of a driver; an electric motor (7) having a rotor shaft operatively connected to at least one steered wheel (9) of the motor vehicle to apply a steering torque to the steered wheel (9) in accordance with a driver steering request; and a rotor position sensor (10) arranged on the rotor shaft, characterized in that the rotor position sensor (10) is formed according to any one of claims 1 to 10.

Technical Field

The present invention relates to a rotor position sensor for determining the angular position of a rotor shaft of an electric motor according to the preamble of claim 1 and a steering system for a motor vehicle with a rotor position sensor according to the preamble of claim 10.

Background

In electric motors, in particular in polyphase brushless dc motors, the commutation is preferably carried out in a sensor-controlled manner by means of a rotor position sensor which determines the angular position of the rotor shaft of the electric motor. Known rotor position sensors are based on the magnetic measurement principle: the magnetic field of at least one magnet connected in a rotationally fixed manner to the rotor shaft is detected by a magnetic field sensor, for example a hall sensor, an AMR or a GMR sensor, and is output in the form of a rotor position signal. Such rotor position sensors are used in particular in electric motors of steering systems of motor vehicles, which provide an electric auxiliary steering force.

In order to increase the operational reliability of such a rotor position sensor, it is known from EP 2752645 a2 to redundantly detect the rotor position and to provide an error detection system which is suitable for excluding error signals from redundantly detected rotor position signals. A disadvantage is that despite the redundant design of the rotor position sensor, due to its measurement principle, it is still susceptible to disturbances, such as stray magnetic fields, which occur in motor vehicles, in particular from current-carrying lines. This problem increases as the degree of electrification of power components in motor vehicles, especially in drive trains, increases. At the same time, as automobiles are increasingly being driven automatically, the requirements for the operational safety of rotor position sensors are also increasing.

From the field of steering shaft sensors, for example from DE 102009027191 a1, a device for determining the torque and/or rotation angle of a shaft is known, which has a circuit carrier concentric to the shaft, on which at least two current-conducting conductor track sections are arranged, and a transmitter element concentric to the shaft and rotatable relative to the circuit carrier, which transmitter element has at least one first partial region made of an electrically conductive material and at least one partial region made of an electrically non-conductive material. When a torque is applied on the shaft, the transmitter element rotates relative to the circuit carrier, whereby the inductance of the conductor track section changes. Disadvantageously, in the proposed sensor, the measurement range is reduced as soon as redundant measurement results are to be generated, which requires an additional indexing function.

Disclosure of Invention

It is therefore an object of the present invention to provide a rotor position sensor and a steering system for a motor vehicle, which are improved in terms of functionality and operational reliability while being of compact and inexpensive design.

This object is achieved by a rotor position sensor having the features of claim 1 and a motor vehicle steering system having the features of claim 10.

This results in a rotor position sensor for determining the angular position of the rotor shaft of an electric motor, having a transmitter element which can be fixed at the end to the rotor shaft, which transmitter element has at least one centrally arranged transmitter magnet and has at least one magnetic field sensor which can be positioned opposite the transmitter magnet on a circuit carrier over the extension of the motor shaft. The magnetic field sensor is formed for outputting a first sensor signal dependent on the angular position of the transmitter element. At least one electrically conductive region defined in the circumferential direction around the transmitter magnet is also provided on the transmitter element for inductively interacting with a coil system provided on the circuit carrier in order to generate a second sensor signal as a function of the angular position of the transmitter element.

The rotor position sensor according to the invention is equipped with diversified redundancies. This diversified redundancy is based on combining magnetic and inductive measurement principles on a single transmitter element to determine the rotor position. The two measurement principles for generating the first and second sensor signals are based on different frequency ranges, thereby minimizing the risk of electromagnetic stray field interference. The magnetic field sensor detects the magnetic field of the transmitter magnet rotating at the engine speed, while the induction principle is preferably based on an alternating field in the MHz range generated by the coil system. This increases the functional and operational reliability.

It is also advantageous to have a space-saving arrangement of the magnetic and inductive transmitters on a single transmitter element, wherein the conductive region of the inductive transmitter can simultaneously provide shielding against stray fields acting on the magnetic field sensor. The evaluation electronics of both measurement principles are arranged on a single circuit carrier. The emitter element is preferably designed in the form of a disc. The central transmitter magnet is preferably surrounded by electrically conductive regions regularly spaced in the azimuthal direction. The emitter magnet is preferably formed as a relatively magnetized disc magnet.

The rotor position sensor may also comprise an evaluation unit for evaluating the first and second sensor signals, which evaluation unit is designed to carry out a disturbance field detection and to provide one of the sensor signals at an output of the evaluation unit with the respective other sensor signal if the other sensor signal deviates from an expected signal profile. The error detection can be carried out, for example, by evaluating the correlation with an expected signal profile stored in the evaluation unit. Alternatively or additionally, template recognition may be performed to identify expected error patterns in the signal profile of the sensor signal.

Preferably, at least two electrically conductive regions are provided, which are spaced apart from one another in the circumferential direction, and the coil system and the magnetic field sensor each have at least twice the redundancy, in order to generate at least two first sensor signals and two second sensor signals. The redundancy of the sensor system can be increased by doubling the redundancy to at least quadruple redundancy, which is required in future autonomous vehicles. Since there are at least four independent measurement signals in total, a fault signal can be identified and discarded. This degree of redundancy cannot be achieved using a single measurement principle, or only in sensors of significantly larger size.

In a preferred embodiment, the coil system comprises at least one transmitting coil for generating an alternating field and at least one receiving coil for detecting an alternating field locally influenced by at least one electrically conductive region of the transmitter element. By using a coil system with a transmitting coil and a receiving coil, an inductive measuring principle is achieved which is less sensitive to mechanical tolerances and temperature fluctuations.

In this case, the transmitting coil generates an alternating magnetic field, which induces a voltage in the receiving coil. The induced voltage depends on the inductive coupling between the transmitter coil and the receiver coil, which is influenced by the conductive areas on the transmitter element. Eddy currents are induced in the conductive region, which locally weaken the alternating field. In this way, a lower induced voltage is generated in the receiving coil depending on the overlap of the conductive area with the receiving coil. Alternatively, instead of or in addition to the induced voltage, the current induced in the receiving coil may also be measured.

The coil system may have a number of receiving coils corresponding to the number of conductive areas of the transmitter element. Thus, each conductive area of a transmitter element is currently assigned a receiving coil for determining the position of the respective transmitter element.

However, the number of receiving coils may also be different from the number of conductive areas. In particular, a greater number of receiving coils than conductive areas may be provided. This provides the advantage that the current sensor signals of the receiving coils differ from each other and that their combination clearly encodes the current angular position. Furthermore, the angular resolution of the sensor is improved.

The conductive areas may differ from each other in their conductivity and/or permeability. Thus, the respective regions can cooperate with the coil system to generate sensor signals of different intensities. In this way, a measuring range of 360 ° can be achieved in the redundant inductance measurement.

The at least two receiving coils are preferably arranged on the circuit carrier in a rotationally symmetrical manner.

The receiving coil preferably has at least one turn which surrounds the magnetic field sensor eccentrically. By arranging the magnetic field sensors in the turn planes of the receiving coil, the influence of the rotating transmitter magnet on the induced voltage in the receiving coil is reduced. When the magnet rotates within the turn surface of the coil, the magnetic flux passing through the surface hardly changes, thereby reducing the influence on the induced voltage.

The transmitting coil is preferably formed symmetrically around the center of the magnetic field sensor. In this way, an alternating field is generated that is symmetrical with respect to the axis of the motor shaft, which allows the same inductive coupling regardless of the azimuthal arrangement of the receiver coils. However, coil systems with a plurality of transmitting coils are also conceivable. For example, one transmitting coil may be assigned to each receiving coil, the transmitting coils preferably being formed to coincide with each other.

In some implementations, the second sensor signal may be generated by detecting an inductance of a coil of the coil system depending on the angular position of the transmitter element. Here, for example, the self-inductance of a coil overlapping with the conductive area or the mutual inductance between the transmitter coil and the receiver coil may be measured.

The conductive areas may be made of a soft magnetic material. This further improves the magnetic shielding of the centrally arranged magnetic field sensor and thus the insensitivity of the sensor to interference influences.

The object is also achieved by a steering system for a motor vehicle comprising a steering handle for inputting a driver steering request, an electric motor, a rotor shaft of which is operatively connected with at least one steered wheel of the motor vehicle for applying a steering torque to the steered wheel in accordance with the driver steering request, and a rotor position sensor arranged on the rotor shaft as described above.

Further embodiments of the invention can be found in the following description and the dependent claims.

Drawings

The invention is explained in more detail below with reference to an embodiment shown in the drawings.

Figure 1 schematically shows an embodiment of a steering system with a rotor position sensor according to the invention,

figure 2 schematically shows the structure of a rotor position sensor according to the embodiment of figure 1,

figure 3 schematically shows the structure of a circuit carrier of a rotor position sensor according to the embodiment of figures 1 and 2,

fig. 4 schematically shows the structure of the transmitter element of the rotor position sensor according to the embodiment of fig. 1 and 2.

Detailed Description

In fig. 1, a structure of a steering system 1 for a motor vehicle according to one embodiment of the present invention is schematically shown. The steering system 1 shown in fig. 1 is formed as an electromechanical motor vehicle power steering apparatus. However, the rotor position sensor according to the invention may also be used in any other steering system with an electrically generated steering torque, in particular in a Steer-by-Wire (Steer-by-Wire) steering system, for example with a gear steering or a single wheel steering.

The steering system 1 comprises a steering wheel attached to a steering shaft 2 as a steering handle 3 for inputting a steering request of a driver, an electric motor 7, the rotor shaft of which is operatively connected with two steered wheels 9 of the motor vehicle (only one steered wheel 9 is shown in fig. 1) for applying a steering torque to the steered wheels 9 in accordance with the steering request of the driver, and a rotor position sensor 10 arranged on the rotor shaft of the electric motor 7. The steering request of the driver can be detected by a steering shaft sensor 4 arranged on the steering shaft 2, electronically processed if necessary together with other input variables and fed to the electric motor 7.

In the electromechanical power steering system of the motor vehicle shown, the steering request of the driver is additionally transmitted mechanically via the steering shaft 2 and the steering gear 5 to the rack 6, the displacement of which is transmitted via the tie rods 8 to the steered wheels 9. The electric motor 7 applies an assist steering torque to the rack bar 6. Alternatively, the electric motor 7 can also be arranged in the region of the steering shaft 2 and introduce an auxiliary steering torque into the steering shaft 2.

Fig. 2 shows a detailed illustration of the rotor position sensor 10 according to fig. 1. The rotor position sensor 10 is used to determine the angular position of the rotor shaft of the electric motor 7. For this purpose, a transmitter element 11 is fixed to the end of the rotor shaft. In this embodiment the transmitter element 11 is formed in the shape of a circular disc and is preferably fixed at its centre point to the rotor shaft. The fastening on the motor shaft is arranged on the side of the transmitter element 11 facing away from the circuit carrier 13.

The transmitter element 11 has a centrally arranged transmitter magnet 12. The emitter magnet 12 is preferably a disk magnet magnetized to opposite poles.

The rotor position sensor 10 also has a magnetic field sensor 14 (see fig. 3) located opposite the transmitter magnet 12 on the circuit carrier 13 over the extension of the motor shaft, which is formed for outputting a first sensor signal as a function of the angular position of the transmitter element 11. For evaluating and processing the sensor signals, an evaluation unit 20 is also arranged on the circuit carrier.

The magnetic field sensor may be formed as a hall element. However, preferably magnetoresistive sensors are used, such as AMR or GMR elements. The magnetic field sensor 14 is preferably formed for determining the direction and orientation of the magnetic field generated by the transmitter magnet 12.

On the transmitter element 11 there is also at least one electrically conductive region 15 defined circumferentially around the transmitter magnet 12 for inductive interaction with a coil system 16 arranged on the circuit carrier 13 to generate a second sensor signal dependent on the angular position of the transmitter element 11. The coil system 16 may be excited by the analysis unit 20 to generate a second sensor signal. For example, the coil system 16 may interact with one or more resonance circuits arranged in the analysis unit 20.

In the exemplary embodiment shown, the transmitter element 11 has a plurality of uniform conductive regions 15 which are regularly spaced apart from one another in the circumferential direction. In particular four conductive areas 15 may be provided.

Preferably, at least two electrically conductive regions 15 are provided, which are spaced apart from one another in the circumferential direction, and the coil system 16 and the magnetic field sensor 14 each have at least a double redundancy for generating at least two first sensor signals and two second sensor signals. For this purpose, the magnetic field sensor 14 preferably has at least two sensor cores for independent measurement and the coil system 16 comprises at least two coils that can be excited independently. By using a combination of inductive and magnetic measuring principles, the rotor position sensor can exclude various external interference fields.

In fig. 3, the circuit carrier 13 of the rotor position sensor 10 according to fig. 1 and 2 is shown, on which the coil system 16, the magnetic field sensor 14 and the evaluation unit 20 are arranged. The coil system 16 has a transmitting coil 17 for generating an alternating field and a plurality of receiving coils 18 for detecting the alternating field locally influenced by at least one electrically conductive region 15 (see fig. 2) of the transmitter element 11.

The transmitting coil 17 is preferably formed so as to be symmetrical, for example circular, about the center of the magnetic field sensor 14. The transmitting coil 17 can be arranged in the outer edge region of the circuit carrier 13 in order to optimize the installation space required for the rotor position sensor 10.

The coil system 16 preferably has a number of receiving coils 18 corresponding to the number of conductive areas 15 of the transmitter element 11. In the embodiment shown, the number of receiving coils 18 and conductive areas 15 is four.

The receiving coil 18 is arranged on the circuit carrier 13 in a rotationally symmetrical manner and has one or more closed turns 19, which eccentrically surround the magnetic field sensor 14. The turns 19 of the receiving coil 18 around the magnetic field sensor 14 contribute to the electromagnetic shielding of the magnetic field sensor 14.

The second sensor signal may be generated, for example, by detecting the inductance of the coils 17, 18 of the coil system 16, which depends on the angular position of the transmitter element 11. In particular, the voltage induced in the receiver coil 18 may be measured to be used as a measure of the mutual inductance of one of the transmitter coil 17 and the receiver coil 18. Alternatively or additionally, the coil system 18 may also measure the self-inductance of a single coil, for example by monitoring the frequency of the oscillations excited in that coil.

In fig. 4, the transmitter element 11 of the rotor position sensor 10 according to fig. 1 and 2 is shown in a top view. As already explained, the transmitter element 11 has a central transmitter magnet 12 magnetized in opposite polarity, around which electrically conductive regions 15 are arranged, which are spaced apart from one another in azimuth. The conductive regions 15 are preferably spaced apart from each other by non-conductive regions 21. The non-conductive areas 21 may also be designed as indentations in the conductive plate. The conductive area 15 is preferably formed in the shape of a circular ring segment.

The transmitter magnet 12 as a magnetic transmitter is connected in a rotationally fixed manner by a connecting section 22 to the electrically conductive region 15 as an inductive transmitter. The connecting section 22 can also be made partially or completely of an electrically conductive material.

The conductive areas 15 are preferably made of a soft magnetic material to improve the magnetic shielding of the magnetic field sensor 14 against interfering fields. The connecting section 22 can likewise be made of a soft-magnetic material. The conductive regions 15 and/or the connection sections 22 can also be made of paramagnetic or diamagnetic material.

Description of the reference numerals

1 steering system

2 upper steering shaft

3 steering handle

4 steering shaft sensor

5-steering transmission device

6 rack

7 electric motor

8 steering tie rod

9 steering wheel

10 rotor position sensor

11 emitter element

12 emitter magnet

13 Circuit Carrier

14 magnetic field sensor

15 conductive region

16-coil system

17 transmitting coil

18 receiving coil

19 turns

20 analysis unit

21 non-conductive area

22 connect the segments.