steering system and vehicle

Abstract

The invention relates to a steering system (2) for steering a vehicle (1), comprising a steering unit (10) for influencing the steering direction of the vehicle (1), a drive unit (11) for driving the steering unit (10) with a rotary element (12) for performing a rotational movement (200) to influence the steering direction, an electronic unit (20) which is supplied with energy for detecting a first rotational parameter (201) of the rotational movement (200) and can be brought into a deactivated state in which the energy supply to the electronic unit (20) is interrupted, and a control unit (30) for detecting a steering position of the steering unit (10) as a function of the first rotational parameter (201). The invention further relates to a vehicle (1).

Description

[0001] The invention relates to a steering system for steering a vehicle, as well as a vehicle.

[0002] It is known from the prior art to measure a steering angle in steering systems in order to record the current wheel position for control tasks in the vehicle. In particular, in steer-by-wire steering systems, an absolute position measurement is often advantageous for determining the rack position. Position determination should generally be significantly more precise than in conventional steering systems with a mechanical coupling to the steering wheel. Furthermore, due to the elimination of the mechanical coupling in steer-by-wire steering, other sensors in the vehicle, e.g., on the steering wheel, can often no longer be used. This places particular demands on the accuracy and reliability of the sensor technology and thus also represents a cost factor.

[0003] For absolute position measurement, sensors are often used that can detect the angle of rotation within one revolution of a rotating component of the respective steering system. The number of revolutions is then also recorded, e.g., by software-supported counting. One possibility for position measurement on a servo motor of a steering system is known, for example, from document WO 2020 / 182522 A1. Furthermore, a rotor position sensor is known from WO 2015 / 067530 A1.

[0004] A common disadvantage of known solutions is that conventional sensors often require power to perform position measurement. This, however, means that a change in the steering position cannot be detected when the vehicle is de-energized, or the assignment to a specific rotational speed cannot be made, resulting in the loss of the absolute position. For example, if the vehicle is in a workshop, the steering system can be completely disconnected from all power sources. In this case, the rotational speed is not recorded, so the absolute steering position is unknown when the vehicle is subsequently restarted.

[0005] It is an object of the present invention to at least partially remedy the above-mentioned disadvantages known from the prior art. In particular, it is an object of the present invention to improve the safety and / or reliability of a steering system, preferably also in special situations.

[0006] The above object is achieved by a steering system having the features of claim 1 and a vehicle having the features of claim 10. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the steering system according to the invention naturally also apply in connection with the vehicle according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0007] According to a first aspect of the invention, a steering system for steering a vehicle is provided. The steering system comprises a steering unit for influencing a steering direction of the vehicle, i.e., in particular a direction of travel of the vehicle, and a drive unit for driving the steering unit. The drive unit has a rotational element for performing a rotational movement to influence the steering direction. Furthermore, the steering system comprises an electronic unit that can be brought into an active state, in which the electronic unit is supplied with energy to detect a first rotational parameter for detecting a rotational speed of the rotational element, and into a deactivated state, in which the energy supply to the electronic unit is interrupted. Furthermore, the steering system comprises a control unit for detecting a steering position of the steering unit as a function of the first rotational parameter.The electronic unit has a first detection unit with a detection means. In the deactivated state of the electronic unit, and preferably also in the active state, the detection means can be electromagnetically changed by an electromagnetic interaction with the rotating element depending on the first rotation parameter of the rotational movement of the rotating element, so that the first rotation parameter for detecting the steering position can be detected in the active state of the electronic unit based on the electromagnetic change of the detection means.

[0008] The vehicle can preferably be a motor vehicle, e.g., an electric vehicle. The steering system can preferably be a steer-by-wire steering system. A rack of the steering unit can be movable to influence the steering direction.

[0009] The drive unit can comprise an electric motor for driving the steering unit to perform a steering movement in order to influence the steering direction. Furthermore, the drive unit can be integrated into the steering unit. The steering unit and / or the drive unit can be controllable as a function of a movement of a steering means, such as a steering wheel. It can be provided that the control unit is designed to control the steering unit and / or the drive unit. The rotation element can be, for example, an output shaft of the electric motor. Advantageously, the rotation element can be designed to drive a belt drive through the rotational movement, preferably via which the rack is movable.

[0010] The electronics unit can comprise electronic components for detecting the first rotation parameter and / or additional sensors of the steering system. The electronics unit can also advantageously be integrated into a control unit of the steering system. In the deactivated state, the electronics unit can be de-energized. The electronics unit is preferably arranged at a shaft end of the rotating element.

[0011] The control unit can be designed to calculate the steering position based on the first rotation parameter. The control unit can comprise a processor and / or a microprocessor. Thus, the control unit can in particular also be referred to as a computing unit. Furthermore, the control unit can be at least partially or completely integrated into a central control unit of the vehicle. However, it is also conceivable for the control unit to be at least partially or completely integrated into one or more decentralized control units. Preferably, the control unit is integrated into the electronics unit. In particular, the control unit and the electronics unit can be part of an ECU for the steering system. In particular, the control unit can also be deactivated when the electronics unit is deactivated, i.e., in particular, de-energized, and / or the detection of the steering position can be prevented.

[0012] The first rotation parameter can, for example, comprise and / or make computationally determinable a number of completed revolutions and / or revolution segments of the rotation element, in particular in one direction and / or starting from a reference. The revolution segments can be understood as a number of finite angular segments into which the rotation of the rotation element can be divided. For example, the rotation parameter can comprise a number of revolution segments in the form of whole and / or half revolutions and / or quarter revolutions. Based on the revolution segments, the number of revolutions can be calculated, e.g., by the control unit.

[0013] For the electromagnetic interaction of the sensing means with the rotating element, the rotating element can be magnetized and / or comprise a magnet, in particular in the form of a permanent magnet. The magnetic change of the sensing means can, for example, comprise a polarization and / or magnetization, in particular of subsections, of a material of the sensing means as a function of the current. For this purpose, the sensing means can comprise a magnetizable and / or magnetically polarizable material, preferably in the form of a coil. Furthermore, the sensing means can be electrically conductive, so that the magnetic change is measurable as a function of a current parameter, e.g., an electrical resistance of the sensing means. Preferably, the electromagnetic change can be based on a GMR effect. The sensing means can advantageously comprise a GMR sensor, in particular in the form of a GMR multiturn sensor.

[0014] Thus, within the scope of the invention, it has been recognized that the electromagnetic variability of the detection means enables detection of the first rotation parameter, and thus in particular the rotational speed, even when the electronic unit and the control unit are not powered. The magnetic change thereby forms, in particular, a memory function, through which the first rotation parameter can be retrieved when the electronic unit is again in the active state. In the active state, the electronic unit can, for example, perform an electrical measurement to measure the state of the detection means and thereby detect the electromagnetic change. This enables a reliable position measurement of the rotation element and thus of the steering unit.

[0015] Within the scope of the invention, it is further conceivable for the first detection unit to have at least one sensor element for detecting a second rotation parameter of the rotational movement in the active and / or deactivated state of the electronic unit, wherein the control unit is designed to determine the steering position based on a combination of the first and second rotation parameters. The second rotation parameter can preferably comprise an angular measurement of a rotation angle of the rotation element within one revolution and / or a revolution segment. For example, the sensor element can be designed to measure an angle of rotation within a rotation of the rotation element by 360° and / or by 180°. For this purpose, the sensor element can be designed, for example, as a magnetoresistive sensor, preferably as an AMR sensor, TMR sensor and / or Hall sensor.The combination of the first and second rotation parameters can include at least one computational operation. For example, the first and second rotation parameters can be converted into the steering position using a mathematical function. Thus, the sensor element can improve the accuracy of determining the steering position.

[0016] It is further conceivable in a steering system according to the invention for the electronic unit to be designed to measure the electromagnetic change in the detection means, preferably based on a resistance measurement of the detection means. The resistance measurement can, in particular, reveal a polarization state of the detection means. For the resistance measurement, the detection means can be energized via an electrical connection and / or by induction when the electronic unit is in the active state. For this purpose, the detection means can be electrically connected to a power supply system and / or a measuring element of the electronic unit. As a result, the electromagnetic change in the detection means can advantageously be measured and processed with a high degree of accuracy.

[0017] Furthermore, in a steering system according to the invention, it can advantageously be provided that the electronics unit has a second detection unit with a detection means which, in the deactivated state of the electronics unit, can be electromagnetically changed by an electromagnetic interaction with the rotation element as a function of the first rotation parameter, and / or a sensor element for detecting the second rotation parameter, wherein the second detection unit is designed redundantly to the first detection unit. The second detection unit can be constructed identically to the first detection unit. Preferably, the detection means and / or sensor elements of the first and second detection units can each be constructed identically. In particular, the first and second detection units can each have their own power supply and / or communication connection to the control unit for redundancy.The second detection unit can thus increase the reliability of detecting the steering position.

[0018] Furthermore, in a steering system according to the invention, it can advantageously be provided that the electronics unit has an energy supply system with at least a first energy supply network for supplying the first detection unit, in particular with electrical energy, and a second energy supply network for supplying the second detection unit, in particular with electrical energy, wherein the first and second energy supply networks are or can be connected to an energy source of the vehicle, in particular for an independent energy supply from one another. The energy sources for the first and second energy supply networks can differ from one another. For example, it is conceivable that the first energy supply network can be connected to a vehicle battery, in particular in the form of a traction battery, of the vehicle and / or the second energy supply network can be connected to an intermediate storage device for an emergency power supply.Furthermore, the first and second power supply networks can be connected to different on-board power systems, particularly in the form of low-voltage networks, of the vehicle. Thus, the power supply networks can increase the reliability of the first and second detection units.

[0019] Furthermore, in a steering system according to the invention, it can advantageously be provided that the first and second detection units are arranged symmetrically to one another with respect to a rotational axis of the rotational element. The rotational axis can in particular be a geometric axis of the rotational element about which the rotational element can be rotated to drive the steering unit. In the symmetrical arrangement, the first and second detection means can each have the same distance from the rotational axis. Furthermore, the first and second sensor elements can each have the same distance from the rotational axis. In this case, the first and second detection units can be electrically and / or magnetically insulated from one another at the rotational axis. This can reduce mutual interference and / or improve redundancy.

[0020] Furthermore, in a steering system according to the invention, it can advantageously be provided that the electronics unit has a printed circuit board with a first side facing the rotation element and a second side facing away from the rotation element, in particular wherein the first detection unit and / or the second detection unit is arranged on the second side of the printed circuit board. However, it is also conceivable for the first and second detection units to be arranged on the first or second side of the printed circuit board. The printed circuit board can in particular be a circuit board with a plurality of electronic components. The printed circuit board can be oriented perpendicular to the axis of rotation, such that the first side of the printed circuit board faces an end face of the rotation element. Preferably, the magnet of the rotation element can be arranged on the end face or form the end face.This allows the magnetic change of the detection means to be defined in relation to the rotation of the rotating element. By arranging the two detection units on opposite sides of the circuit board, the two detection units can be spaced at different distances from the rotating element. This allows the interaction of the detection means of the first and second detection units with the rotating element to varying degrees, making it easier to detect a fault based on deviations. Furthermore, a fault on one side of the circuit board can affect only one of the two detection units.By arranging the first and second detection units on the first side of the circuit board, both detection units can have the same distance from the rotation element, in particular so that a failure of one of the two detection units has no or almost no influence on the accuracy of the detection of the steering position.

[0021] Within the scope of the invention, it is further conceivable for the first and second detection units to form a common structural unit or to be divided into several structural units for arrangement on the circuit board. If the first and second detection units form a common structural unit, it can be provided that the first and second detection units are arranged in a common housing and / or are formed by a split electronic component, in particular in the form of a chip. Each detection unit can preferably comprise a semiconductor die which has the detection means and the sensor element of the respective detection unit. For redundancy, the two semiconductor dies can each be connected to a different power supply network. Thus, by designing the first and second detection units as a common structural unit, simple production and / or assembly of the electronic unit can be enabled.By designing the device with multiple separate components, the first and second detection units and / or the detection means and sensor units can be handled and / or positioned independently of one another. In particular, the first and second detection units and / or the detection means and sensor units can each comprise their own housing and / or be formed by a separate electronic component, particularly in the form of a chip and / or semiconductor die.

[0022] Furthermore, in a steering system according to the invention, it can advantageously be provided that an additional detection unit is provided which comprises two sensor elements, preferably which have a cross-connection to the first and second detection units in the energy supply system. The sensor elements of the additional detection unit can be constructed identically to or differently from the sensor element of the first and / or second detection unit. Preferably, the sensor elements of the additional detection unit can be designed, for example, as a magnetoresistive sensor, preferably as an AMR sensor, TMR sensor and / or Hall sensor. Cross-connection can be understood to mean that one of the two sensor elements of the additional detection unit is connected to the first energy supply network and another of the two sensor elements of the additional detection unit is connected to the second energy supply network.The additional detection unit is preferably arranged on the first or second side of the circuit board. The two sensor elements of the additional detection unit can be formed by a separate electronic component, in particular in the form of a chip and / or semiconductor die, and / or have a common housing. However, it is also conceivable for the additional detection unit to be divided between the first and second sides, so that one of the two sensor elements of the additional detection unit is arranged on the first side and the other sensor element of the additional detection unit is arranged on the second side. The additional detection unit, in particular in conjunction with the cross-connection, can further improve the availability and reliability of detecting the steering position.In particular, if the sensor elements of the additional detection unit are designed as TMR sensors and arranged on the first side of the circuit board, a stronger magnetic field can be generated due to the smaller distance to the rotating element compared to the second side. This allows for particularly reliable measurements.

[0023] According to a further aspect of the invention, a vehicle is provided. The vehicle has a steering system according to the invention.

[0024] Thus, a vehicle according to the invention brings with it the same advantages as have already been described in detail with reference to a steering system according to the invention.

[0025] Further advantages, features, and details of the invention will become apparent from the following description, which describes embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. They show schematically: Fig. 1 a vehicle with a steering system according to the invention, Fig. 2 to 4 electronic units of the steering system in different designs, and Fig. 5 an energy supply system of the steering system.

[0026] In the following description of some embodiments of the invention, the same reference numerals are used for the same technical features even in different embodiments.

[0027] Fig. 1 shows a vehicle 1 according to the invention with a steering system 2 according to the invention for steering the vehicle 1 in a first exemplary embodiment. The steering system 2 has a steering unit 10 for influencing a steering direction of the vehicle 1 and a drive unit 11 for driving the steering unit 10. For this purpose, the drive unit 11 further comprises a rotational element 12 for performing a rotational movement 200 to influence the steering direction. The rotational element 12 is designed in particular as a drive shaft that cooperates with a belt drive 13 to move a rack 14 of the steering unit 10.

[0028] Furthermore, the steering system 2 comprises a control unit 30 for detecting a steering position, e.g., in the form of a position of the rack 14, of the steering unit 10 as a function of a first rotation parameter 201 of the rotation element 12 for detecting a rotational speed of the rotation element 12 and a second rotation parameter 202 for detecting a rotation angle of the rotation element 12 within a revolution and / or a revolution segment. For this purpose, it can be provided that the control unit 30 determines, i.e., in particular calculates, the steering position based on a combination of the first and second rotation parameters 201, 202. The control unit 30 is further integrated into an electronic unit 20 of the steering system 2 for detecting the first and second rotation parameters 201, 202. In an active state, the electronic unit 20 is supplied with energy for detecting the first and second rotation parameters 201, 202.Furthermore, a deactivated state of the electronic unit 20 can occur in which the power supply is interrupted. The power supply can, in particular, be a voltage supply, so that the electronic unit 20 is de-energized in the deactivated state. The deactivated state can be generated by a fault or intentionally, e.g., for maintenance of the vehicle 1.

[0029] As in the Fig. 2 to 4 in different embodiments of the electronic unit 20, the electronic unit 20 has a first detection unit 40 with a detection means 41 for detecting the first rotation parameter 201 and a sensor element 42 for detecting the second rotation parameter 202. The detection of the first and second rotation parameters 201, 202 takes place electrically in the active state of the electronic unit 20 in order to make the first and second rotation parameters 201, 202 available to the control unit 30.

[0030] In order to detect the rotational movement 200 of the rotational element 12 in the deactivated state, the detection means 41 of the electronic unit 20 can be electromagnetically changed in the deactivated state, and preferably also in the activated state, by an electromagnetic interaction with the rotational element 12 as a function of the first rotational parameter 201 of the rotational movement 200 of the rotational element 12, so that the first rotational parameter 201 for detecting the steering position in the active state of the electronic unit 20 can be detected based on the electromagnetic change in the detection means 41. For the electromagnetic interaction with the detection means 41, the rotational element 12 comprises a magnetic element 12.1, which is preferably arranged at one end of the rotational element 12. The magnetic change stores the first rotational parameter 201 of the rotational movement 200 in the deactivated and activated states.The electronic unit 20 is designed to measure the electromagnetic change of the detection means 41 based on a resistance measurement of the detection means 41, in particular after the active state has been restored.

[0031] Preferably, the detection means 41 is designed as a GMR sensor, and the sensor element 42 as a TMR sensor, AMR sensor, and / or Hall sensor. This allows the steering position to be advantageously calculated from the combination of the first and second rotation parameters 201, 202.

[0032] To ensure high availability of steering position detection, the electronics unit 20 further comprises a second detection unit 43, which is redundant to the first detection unit 40. For this purpose, the second detection unit 43 also has a detection means 41, which, in the deactivated state of the electronics unit 20, can be electromagnetically changed by electromagnetic interaction with the rotation element 12 as a function of the first rotation parameter 201, and a sensor element 42 for detecting the second rotation parameter 202. For advantageous arrangement and assembly, the electronics unit 20 has a printed circuit board 44 with a first side 44.1 facing the rotation element 12, in particular an end face of the rotation element 12, and a second side 44.2 facing away from the rotation element 12. The printed circuit board 44 is preferably perpendicular to a rotation axis 200.1 of the rotational movement 200 of the rotational element 12, in particular spaced from an end face of the rotational element 12.

[0033] Furthermore, the electronics unit 20 has an additional detection unit 47 comprising two sensor elements 42. The sensor elements 42 of the additional detection unit 47 can be identical to or different from the sensor elements 42 of the first and second detection units 40, 43. The additional detection unit 47 can further increase the availability of detecting the steering position.

[0034] As in Fig. 2, the first and second detection units 40, 43 can advantageously be arranged symmetrically to one another on the second side 44.2 of the circuit board 44 with respect to the rotation axis 200.1 of the rotation element 12. As a result, the first and second detection units 40, 43 can be protected by the circuit board 44 and / or a distance from the magnetic element 12.1. In this case, the first and second detection units 40, 43, as shown in Fig. 2, a common unit 45 or, as shown in Fig. 3, be divided into several units 46. Furthermore, the additional detection unit 47 is preferably arranged on the first side 44.1 of the printed circuit board 44, as shown in the Fig. 2 and Fig. 3, so that the additional detection unit 47 experiences a greater field strength of the magnetic field of the magnetic element 12.1.

[0035] However, it is also conceivable that the first detection unit 40 is arranged on the second side 44.2 of the circuit board 44 and the second detection unit 43 is arranged on the first side 44.1 of the circuit board 44, as in Fig. 4, or vice versa. The sensor units of the additional detection unit 47 can also be divided between the first and second sides 44.1, 44.2. This allows different magnetic field strengths to be detected in order to detect a fault in the electronics unit 20 and / or to provide redundancy in the event of a failure of the entire first or second side 44.1, 44.2 of the circuit board 44.

[0036] As in Fig.5, the electronics unit 20 further comprises a power supply system 50 with at least a first power supply network 51 for supplying the first detection unit 40 and a second power supply network 52 for supplying the second detection unit 43. To establish redundancy, the first and second power supply networks 51, 52 can each be connected to a power source 53 of the vehicle 1 for an independent power supply from one another. Furthermore, the sensor elements 42 of the additional detection unit 47 have a cross-connection 48 to the first and second detection units 40, 43 in the power supply system 50 in order to also be able to operate them redundantly. In the cross-connection 48, the sensor elements 32 of the additional detection unit 47 are each connected to a different power supply network 51, 52.

[0037] The above explanation of the embodiments describes the present invention exclusively by way of examples. Of course, individual features of the embodiments can be freely combined with one another, provided they are technically feasible, particularly within the scope of protection defined by the patent claims, without departing from the scope of the present invention. List of reference symbols 1 vehicle 2 Steering system 10 Steering unit 11 Drive unit 12 Rotation element 12.1 Magnetic element 13 Belt drive 14 Rack 20 Electronic unit 30 Control unit 40 first recording unit 41 recording means 42 Sensor element 43 second recording unit 44 circuit board 44.1 first page 44.2 second page 45 common building unit 46 separate units 47 Additional recording unit 48 Cross connection 50 Energy supply system 51 first energy supply network 52 second energy supply network 53 Energy source 200 rotational movement 200.1 Rotation axis 201 first rotation parameter 202 second rotation parameter QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 182522 A1

[0003] WO 2015 / 067530 A1

[0003]

Claims

[1] Steering system (2) for steering a vehicle (1), comprising a steering unit (10) for influencing a steering direction of the vehicle (1), a drive unit (11) for driving the steering unit (10) with a rotation element (12) for performing a rotational movement (200) for influencing the steering direction, an electronic unit (20) which can be brought into an active state, in which the electronic unit (20) is supplied with energy for detecting a first rotation parameter (201) for detecting a rotational speed of the rotation element (12), and into a deactivated state, in which the energy supply to the electronic unit (20) is interrupted, and a control unit (30) for detecting a steering position of the steering unit (10) as a function of the first rotation parameter (201), characterized by , that the electronic unit (20) has a first detection unit (40) with a detection means (41), wherein the detection means (41) in the deactivated state of the electronic unit (20) can be electromagnetically changed by an electromagnetic interaction with the rotation element (12) as a function of the first rotation parameter (201) of the rotational movement (200) of the rotation element (12), so that the first rotation parameter (201) for detecting the steering position in the active state of the electronic unit (20) can be detected on the basis of the electromagnetic change in the detection means (41). [2] Steering system (2) according to claim 1, characterized byin that the first detection unit (40) has at least one sensor element (42) for detecting a second rotation parameter (202) of the rotational movement (200) in the active state of the electronic unit (20), wherein the control unit (30) is designed to determine the steering position based on a combination of the first and second rotation parameters (201, 202). [3] Steering system (2) according to claim 1 or 2, characterized by that the electronic unit (20) is designed to measure the electromagnetic change of the detection means (41) based on a resistance measurement of the detection means (41). [4] Steering system (2) according to one of the preceding claims, characterized bythat the electronic unit (20) has a second detection unit (43) with a detection means (41) which, in the deactivated state of the electronic unit (20), can be electromagnetically changed by an electromagnetic interaction with the rotation element (12) as a function of the first rotation parameter (201), and / or a sensor element (42) for detecting the second rotation parameter (202), wherein the second detection unit (43) is designed to be redundant to the first detection unit (40). [5] Steering system (2) according to one of the preceding claims, characterized bythat the electronic unit (20) has a power supply system (50) with at least a first power supply network (51) for supplying the first detection unit (40) and a second power supply network (52) for supplying the second detection unit (43), wherein the first and second power supply networks (51, 52) can each be connected to a power source (53) of the vehicle (1) for an independent power supply from one another. [6] Steering system (2) according to one of the preceding claims, characterized by that the first and second detection units (40, 43) are arranged symmetrically to one another with respect to a rotation axis (200.1) of the rotation element (12). [7] Steering system (2) according to one of the preceding claims, characterized byin that the electronics unit (20) has a printed circuit board (44) with a first side (44.1) facing the rotation element (12) and a second side (44.2) facing away from the rotation element, wherein the first detection unit (40) and / or the second detection unit (43) is arranged on the second side (44.2) of the printed circuit board (44). [8] Steering system (2) according to one of the preceding claims, characterized by that the first and second detection units (40, 43) form a common structural unit (45) or are divided into several structural units (46) for arrangement on the printed circuit board (44). [9] Steering system (2) according to one of the preceding claims, characterized by that an additional detection unit (47) is provided which comprises two sensor elements (42) which have a cross connection (48) to the first and second detection unit (40, 43) in the energy supply system (50). [10] Vehicle (1) comprising a steering system (2) according to one of the preceding claims.

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