Steering system for a motor vehicle

Abstract

The invention relates to a steering system for a motor vehicle, having a rotary sensor, which comprises a magnetic element, which is attached to a steering shaft and which can rotate about an axis of rotation together with the steering shaft, and two stator elements, which are arranged coaxially fixed relative to the steering shaft, which are spaced apart from one another in the axial direction and which are operatively connected to at least one sensor element via two flux conductors, wherein the flux conductors each have a collector portion, a connection portion and a compensator portion, wherein the collector portion is connected to the stator element and the collector portion is connected to the compensator portion via the connection portion, and wherein the sensor element is arranged between the two flux conductors. In order to allow an improved and more robust detection of the steering input, it is proposed that the compensator portion has a compensator surface which is smaller than or equal to the collector surface of the collector portion.

Description

Technical Field

[0001] The present invention relates to a steering system for a motor vehicle having a rotation sensor comprising a magnet and two stator elements. The magnet is attached to a steering shaft and is rotatable about an axis together with the steering shaft. The two stator elements are coaxially fixed relative to the steering shaft, are axially spaced apart from each other, and are operatively connected to at least one sensor element via two flux conductors. In each case, the flux conductors have a collecting portion, a connecting portion, and a compensator portion. The collecting portion is connected to the stator element and is connected to the compensator portion via the connecting portion. The sensor element is disposed between the two flux conductors. Background Technology

[0002] In the electromechanical power-assisted steering system or steer-by-wire system of the type discussed in motor vehicles, a rotation sensor is used to detect manual steering commands. The rotation sensor detects the rotation of the steering shaft caused by manual actuation of the steering handle, and additionally or alternatively, detects the manual steering torque introduced into the steering shaft, thereby generating an electrical control signal to activate the electric steering drive, which results in the corresponding steering lock of the steering wheels.

[0003] To detect rotational motion, rotational sensors with magnetic sensor devices are known. These sensors can be designed as torque sensors or rotational angle sensors, or as a combination of torque and rotational angle sensors. For example, this type of rotational sensor is described in WO 2020 / 174170 A1. The rotational sensor includes a magnetic element and two stator elements arranged rotatably relative to the stator elements and configured such that the magnetic element couples a magnetic flux, depending on the relative angular orientation, into the stator elements. Measuring the magnetic flux coupled into the stator elements allows determination of the rotation of the component with the magnet relative to the stator elements. To implement a rotational angle sensor, the rotational angle of a steering shaft, which is rotatable relative to the stator elements and has a magnet, can be determined by fixing the stator elements so that they do not rotate relative to each other. Torque can be determined by the relative rotation of two steering shaft components connected via a torsional elastic element, such as a torsion bar.

[0004] Two stator elements are formed in a ring shape from a magnetically conductive material, and the two stator elements are coaxially arranged around a magnetic element relative to the axis of rotation. Each stator element has an outer, surrounding attachment portion in the form of a disk, which is coupled to a magnetoelectric sensor element via a magnetic flux conductor. The attachment portion is thus magnetically operatively connected. The sensor element includes, for example, a Hall effect sensor element or a magnetoresistive (GMR) sensor element, in which the magnetic flux introduced via the flux conductor is converted into an electrical signal.

[0005] Each flux conductor has a collecting portion that extends on a collecting surface and connects to an attachment portion of the stator element. Each flux conductor has at least one connecting surface, and the flux conductors are shaped and designed such that the connecting surfaces of the two flux conductors face each other on opposite sides of an air gap. At least one sensor element is disposed between the connecting surfaces. Magnetic flux, or measuring flux, is coupled into the stator element and conducted to the sensor element via the flux conductors by means of an angle-dependent magnetic field generated by a magnetic element—hereinafter referred to as the measurement field.

[0006] Measurements can be affected by external magnetic interference fields that are also coupled to the stator elements from the outside and generate a magnetic interference flux superimposed on the measurement flux. To counteract such interference, it is proposed in the prior art that the flux conductor has at least one compensator section, which is magnetically connected to the collecting section via a connecting portion, and which is spaced a certain distance from the stator elements. Therefore, essentially only the interference field couples to the compensator section. The resulting interference flux is superimposed on the measurement flux coupled to the collecting section with opposite signs, and the interference flux is superimposed on the measurement flux, for example, by axially interchanged arrangements of the collecting section and the compensator section, in which the compensator section of one flux conductor is axially arranged in the region of the collecting section of another flux conductor, and vice versa.

[0007] Existing rotary sensors generally allow for the measurement of rotational motion, even under the influence of disturbances. However, in the steering systems of motor vehicles, the high levels of reliability and safety requirements necessary under specific operating conditions cannot be guaranteed in part.

[0008] In view of the problems explained above, the object of the present invention is to allow for improved and more robust detection of steering inputs in steering systems for motor vehicles. Summary of the Invention

[0009] According to the present invention, this objective is achieved by the steering system of the present invention.

[0010] In the case of a steering system with a rotation sensor for a motor vehicle, the rotation sensor includes a magnet and two stator elements. The magnet is attached to the steering shaft and is rotatable about an axis with the steering shaft. The two stator elements are coaxially fixed relative to the steering shaft, spaced apart from each other in the axial direction, and operatively connected to at least one sensor element via two flux conductors. In each case, the flux conductors have a collecting portion, a connecting portion, and a compensator portion. The collecting portion is connected to the stator element and connected to the compensator portion via the connecting portion. The sensor element is arranged between the two flux conductors. According to the invention, the compensator portion has a compensator surface that is less than or equal to the collecting surface of the collecting portion.

[0011] Furthermore, it can be preferably determined that a significant improvement in the robustness and accuracy of detecting steering input can be achieved because of the steering system for motor vehicles having the following rotation sensor: the rotation sensor includes a magnet and two stator elements, the magnet being attached to the steering shaft and capable of rotating about an axis together with the steering shaft, the two stator elements being coaxially fixed relative to the steering shaft, the two stator elements being axially spaced apart from each other and operatively connected to at least one sensor element via two flux conductors, wherein each flux conductor has a collecting portion, a connecting portion, and a compensator portion, wherein the collecting portion is connected to the stator element and the collecting portion is connected to the compensator portion via the connecting portion, and wherein the sensor element is arranged between the two flux conductors. According to the invention, the steering shaft includes an upper steering shaft connected to a lower steering shaft via a torsion bar, wherein an anti-torsion device arranged on the upper steering shaft engages with an anti-torsion device arranged on the lower steering shaft to limit the torsion of the torsion bar itself, and wherein the compensator portion has a compensator surface smaller than the collecting surface of the collecting portion.

[0012] Furthermore, it can be preferably determined that a significant improvement in the robustness and accuracy of detecting steering input can be achieved because of a steering system for a motor vehicle having a rotation sensor as described below: the rotation sensor includes a magnet and two stator elements, the magnet being attached to the steering shaft and capable of rotating about an axis together with the steering shaft, the two stator elements being coaxially fixed relative to the steering shaft, the two stator elements being axially spaced apart from each other and operatively connected to at least one sensor element via two flux conductors, wherein the flux conductors in each case have a collecting portion, a connecting portion, and a compensator portion, wherein... The collecting section is connected to the stator element and to the compensator section via a connecting section, wherein a sensor element is arranged between two flux conductors. According to the invention, the steering shaft includes an upper steering shaft connected to the lower steering shaft via a torsion bar, wherein an anti-torsion device arranged on the upper steering shaft engages with an anti-torsion device arranged on the lower steering shaft to limit the torsion of the torsion bar itself, and a gear is provided, fixed to one of the two steering shafts and rotationally symmetrical about the torsion bar, wherein the compensator section has a compensator surface smaller than the collecting surface of the collecting section. The gear is preferably connected to an electric actuator via a transmission device.

[0013] Stator elements with a basic ring shape preferably have an attachment portion, which is in the shape of a disk or ring and extends extensively laterally relative to the axis. The attachment portion is also synonymously referred to as an attachment flange. The attachment portions preferably have axial surfaces on their inner sides facing each other and on their outer sides facing away from each other.

[0014] The preferred flat surface area of ​​the collecting portion corresponds by definition to the collecting surface, and correspondingly, the preferred flat surface area of ​​the collecting portion corresponds by definition to the compensator surface. In each case, a collecting portion is magnetically connected to one of these axial surfaces, wherein the collecting surface may be in complete or partial planar contact with the axial surface of the attachment portion. The compensator portion is arranged radially on the outside of the stator element, and the compensator surface preferably extends on the outside of the attachment portion.

[0015] Preferably, the inner and outer surfaces of the attachment portion of the stator element, as well as the collecting surface and the compensator surface, are at least partially flat and laterally oriented relative to the axis, i.e., the inner and outer surfaces of the attachment portion of the stator element, as well as the collecting surface and the compensator surface, have mutually parallel axial surfaces in at least some areas.

[0016] According to the invention, the surface area of ​​the compensator portion is less than or at most equal to the surface area of ​​the collecting portion. This ensures that the portion of the magnetic interference field used to compensate the measurement signal and detected by the compensator portion, also known as the compensation flux, is maintained at an optimal order of magnitude. In particular, overcompensation that could otherwise distort the measurement results can be prevented. This results in higher accuracy in the measurement of rotation angles, leading to greater operational reliability. This is particularly advantageous for motor vehicle steering systems and is highly relevant to operational safety.

[0017] To calculate the surface ratio, it is preferable to use surface projections in a predetermined direction, such as the collecting surface and the compensator surface projected in the axial direction. This ensures that external magnetic interference fields passing through the collecting surface and the interference surface can be better compensated.

[0018] Advantageously, the surface ratio of the collecting surface to the compensator surface is between 1 and 4, meaning the collecting surface is between 1 and 4 times the size of the compensator surface. Further optimization could specify this surface ratio between 1 and 2. A favorable improvement would be to set this surface ratio between 1.5 and 2, or even within a narrower range between 1.5 and 1.75.

[0019] A surface ratio of 1.75 between the collecting surface and the compensator surface is particularly advantageous.

[0020] The optimization effect of the ratio within the scope of the invention, and especially the optimization effect for the aforementioned specific ratio, can be explained by the fact that external interference fields impact the externally exposed compensator surface without obstruction, but the collection surface is at least partially protected from the influence of external interference fields by means of the stator element or the attachment portion of the stator element.

[0021] Furthermore, it has been determined that the anti-torsion device causes localized accumulation of ferromagnetic material in the steering system, which affects the magnetic interference flux caused by external magnetic interference fields by deflecting the flux. A gear positioned on one side relative to a rotation sensor can also affect the magnetic interference flux caused by external magnetic interference fields by deflecting the flux. However, using the solution proposed according to the present invention, such a steering system can represent a considerable improvement in the detection of steering input.

[0022] In the prior art, the causal relationship of the surface ratio based on the present invention has not been recognized or identified as a problem, and therefore, the specific problems arising therefrom when using magnetic rotary sensors in the steering system of motor vehicles have not been resolved. Therefore, the dimensional ratio proposed according to the present invention reproduces the advantageous performance with respect to the steering system of a motor vehicle.

[0023] Another practical advantage is that the compensator protrudes outwards not too far beyond the stator elements, thus occupying less structural space within the steering column.

[0024] Preferably, the flux conductor is formed as a single metal sheet component. The metal sheet component is made of a readily magnetic material, such as an iron sheet with defined magnetic properties. It can be manufactured efficiently through pressing, stamping, precision cutting, bending, embossing, etc. Therefore, the flux conductor can have a substantially continuous, uniform material thickness, which substantially corresponds to the metal sheet thickness. In embodiments where the collecting surface and the compensator surface are oriented laterally relative to the axis, the metal sheet thickness corresponds to the axial thickness of the collecting portion and the compensator portion.

[0025] The preferred thickness of the metal sheet is between 0.6 mm and 1 mm, and particularly preferably 0.8 mm.

[0026] An advantageous implementation can be achieved where the flux conductors cross in the region of the connecting portion between the compensator section and the collecting section, such that the compensator section and the collecting section are axially opposite each other. The axial positions are exchanged here. This means that the collecting section of one flux conductor and the compensator section of another flux conductor are axially located on one side, while the collecting section of another flux conductor and the compensator section of the first flux conductor are axially opposite each other on the other side. This produces an arrangement structure that is mirror-symmetric about a mirror plane that is transverse relative to the axis. As viewed in the circumferential direction, the X-shaped configuration is formed by the connecting line between the collecting section and the compensator section. This allows for effective compensation for the effects of external magnetic interference.

[0027] Advantageously, the compensator surface and the collecting surface of the flux conductor are primarily parallel to each other and parallel to the connection portion of the stator element that connects to the collecting portion. The attachment surface of the stator element is preferably formed in the form of a disk or annulus with an axial surface that connects to the corresponding axial portion of the collecting portion. In each case, "primarily" should be understood as at least 75% of the compensator surface and the collecting surface being oriented parallel to each other.

[0028] Preferably, the collecting portion can be attached to the axially opposite inner portions of the stator element. Thus, the two flux conductors can be axially accommodated between the attached portions in a protected manner and through optimized structural space, wherein the collecting portion contacts the inner axial end side of the attached portion.

[0029] An advantageous implementation is one where the axial distance between the collecting portions is less than the axial distance between the compensator portions. The collecting portions are offset inward in the axial direction relative to the compensator portions. Since the collecting portions are connected to the inside of the attachment portions of the stator elements, improved structural integration and a smaller structural space are possible.

[0030] An optimized improvement can be achieved by aligning the compensator section flush with the attachment portion of the stator element. This means that an axial plane extends through the compensator section and through the disk- or ring-shaped attachment portion; in other words, when viewed radially, the cross-sections of the compensator section and the attachment portion intersect. This can be achieved, for example, by attaching a collecting portion to the inside of the attachment portion and offsetting the collecting portion axially inward relative to the compensator section by the axial thickness of the attachment portion. Therefore, advantages regarding better compensation performance can be achieved, especially in the case of non-uniform disturbance fields.

[0031] To achieve the above-described implementation, the axial distance between the collecting portions can be set to be less than the axial distance between the compensator portions. The axial distance between the outer portions of the collecting portions corresponds here to the distance between the inner portions of the attachment portions of the stator elements.

[0032] It can be configured such that the compensator portion connects to the coupling portion, the coupling portion having a coupling surface facing the sensor element. These coupling portions can be designed as narrow finger-like strips, which are therefore also referred to as flux fingers. The coupling portions protrude into the axial intermediate space between the flux conductors, such that the coupling surfaces, preferably oriented parallel to each other and parallel to the compensator surface, are axially opposed to each other on either side of the sensor element. The coupling surfaces can be magnetically coupled to the sensor element either through direct contact or via a defined air gap. The coupling portion can be formed together with the coupling portion, wherein the coupling portion has at least one coupling surface. Alternatively or additionally, the flux fingers can be formed separately from the coupling portion. Preferably, at least one flux finger can extend from the compensator portion, which is not directly connected to the collection portion, and is spaced a distance from the coupling portion that connects the compensator portion to the collection portion. In the protruding end region of the flux finger, the flux finger can have a coupling surface facing a corresponding coupling surface on the flux finger or a corresponding coupling surface on the coupling portion of another flux conductor. The arrangement and configuration of the connecting parts allow for optimized superposition and compensation of the interference field.

[0033] Sensor elements can be used. Furthermore, it is advantageous to arrange at least two sensor elements spaced apart from each other. Examples of sensor elements that can be used include Hall sensors or magnetoresistive (GMR) sensors. By doubling or multiplying the number of sensors, measurements can be averaged and / or prepared in some other way. This redundancy also improves the security of the device. The sensor elements are preferably spatially distant from each other, and for example, the sensor elements are spaced a distance circumferentially relative to the axis. Therefore, the interference flux coupled to the compensator section can be measured with spatial resolution, allowing for further improvements in compensation for the interference field.

[0034] An advantageous improvement is to have angled wing portions in the compensator section. These wing portions, also synonymously referred to as winglets, form partial or edge portions that are laterally curved relative to the flat, preferably axial, compensator surface, and which may extend substantially parallel to the axis, thus protruding into the intermediate space between the attachment portions of the stator elements. The winglets may preferably point towards a corresponding other compensator section. The axial length of the winglets is preferably less than the axial distance between the compensator sections. One advantage is that the effective area of ​​the compensator section for detecting interference fields can be increased, even for obliquely interfering interference fields. Therefore, the compensation effect can be optimized.

[0035] Advantageously, the flux conductor and sensor element are arranged within a housing. This housing (sensor housing) can be made, for example, of plastic as an injection-molded component, and protects the components housed within it. In an advantageous development, the housing can be filled with a potting compound. This potting compound can be inserted as a liquid resin, which flows around the flux conductor and sensor element and hardens to form a solid block. The flux conductor and sensor element are then securely embedded in this solid block in a material-to-material and / or form-fit manner. Thus, this non-releasable fixation achieves precise positioning, which has a positive impact on long-term stable measurement accuracy.

[0036] It can be configured that the compensator section and / or the collecting section have guide portions. The guide portions allow for guidance and positioning within the housing or on another component of the rotary sensor having corresponding guide elements, such as guide grooves. The guide portions may have, for example, guide protrusions, guide lugs, guide tracks, etc., protruding outward from the compensator section, and can, for example, form a form-fitting guide engagement with the corresponding guide element by being pushed into the guide groove. Therefore, improved positioning and fixation of the flux conductor can be achieved, which is advantageous for both installation and operational reliability.

[0037] It can be configured that the compensator section and / or the collecting section and / or the stator element have stop portions. The stop portions are designed and arranged such that they can abut against corresponding reverse stop portions to achieve mechanical stopping, enabling simple and accurate mechanical positioning relative to each other. The stop portions may have, for example, protrusions that can impact corresponding surfaces or edges. For example, the collecting section may have an axially projecting stop portion that, when installed radially, can impact the outer edge of the attachment portion of the stator element. The collecting section is then precisely positioned relative to the stator element, thus simplifying manufacturing.

[0038] Preferably, the collecting portion of one flux connector and the compensator portion of another flux connector are separated by a certain radial distance, the ratio of which to the radial width of the collecting portion of the other flux conductor is between 0.5 and 2. This allows for further optimization of the compensation effect. This ratio is preferably between 0.75 and 1.5. Furthermore, it is more preferably between 0.75 and 1.25, and even more preferably between 0.8 and 1.2.

[0039] It is particularly advantageous that the ratio of the aforementioned distance to the width is 1, such that the radial distance corresponds to the radial width of the collecting portion.

[0040] It can be specified that the collecting portion of one flux conductor has an axial height difference relative to the compensator portion of another flux conductor, the ratio of this axial height difference to the axial thickness of the collecting portion being between 0.5 and 2. This axial distance corresponds to the thickness of the aforementioned metal sheet. This simplifies the flush alignment of the aforementioned compensator portion with the attachment portion of the stator element. This ratio is preferably between 0.75 and 1.5, or more preferably between 0.75 and 1.25, or even more preferably between 0.8 and 1.2. This allows for improved flush alignment of the compensator portion with the attachment portion of the stator element.

[0041] It is particularly advantageous that the axial height difference mentioned above is equal to the axial thickness, which corresponds to a ratio of 1.

[0042] Advantageously, the collecting portion of one flux conductor may have an axial height difference relative to the compensator portion of the same flux conductor, the ratio of which to the axial height difference between the attachment portions of the two flux conductors is between 0.75 and 2.2. The axial distance between the attachment portions is measured axially between the sides to which the collecting portion is attached, such as the inner sides described above. This ratio may preferably be between 0.85 and 1.2, or particularly preferably between 0.9 and 1.15.

[0043] A value of 1.125 for the aforementioned axial height difference can be particularly advantageous.

[0044] Preferably, in the area where the sensor elements are arranged, the two flux conductors have an axial height distance ranging from 1.8 to 2.2 times the axial thickness of the flux conductors. This height distance refers to the axial gap between the flux conductors, and the axial thickness of the flux conductors corresponds to the thickness of the aforementioned metal sheet.

[0045] It is advantageous that the axial height difference between the flux conductor and the sensor element is less than the axial thickness of the flux conductor. This height distance refers to the air gap existing between the sensor element and the aforementioned connecting surface, and this air gap is intended to be as small as possible to ensure efficient transmission of magnetic flux. If the sheet thickness is used as the axial distance, it is advantageous that the height distance corresponds to 0.6 to 1 times the sheet thickness, particularly preferably to the thickness of a single sheet.

[0046] The axial distance between the connecting portions of the stator elements can be between 10 and 30 times the axial thickness of the flux conductor—which corresponds to the thickness of the aforementioned metal sheet, for example, 0.8 mm. This distance can preferably be between 12 and 25 times, and particularly preferably between 12 and 15 times.

[0047] The aforementioned axial distance, which is equivalent to 15 times the thickness of the metal sheet, is particularly advantageous.

[0048] The angled wing portion (winglet) described above can preferably protrude from the compensation surface by 2 to 7 times the axial thickness (metal sheet thickness) of the compensation portion. The axial height of the winglet can preferably correspond to between 2.5 and 5 times the metal sheet thickness, and particularly preferably to between 2.7 and 3.3 times.

[0049] The wing protruding 3.3 times the thickness of the metal sheet from the compensator section can be particularly advantageous. Attached Figure Description

[0050] The advantageous embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings, in which:

[0051] Figure 1 A schematic 3D diagram of a motor vehicle steering system is shown.

[0052] Figure 2 The diagram illustrates the situation based on the exposed information. Figure 1 A magnified detail of the rotation sensor (=sensor device) of the steering system.

[0053] Figure 3 It shows according to Figure 2 A magnified detail of the rotation sensor.

[0054] Figure 4The stator elements and flux conductors are shown in the schematic perspective view.

[0055] Figure 5 It shows according to Figure 4 The flux conductor is exposed and magnified in the schematic 3D diagram.

[0056] Figure 6 It shows crossing according to Figure 2 Or a partial radial section of the rotating sensor (view viewed in the circumferential direction).

[0057] Figure 7 The axial view shows the results according to Figure 5 Flux conductor,

[0058] Figure 8 A magnified diagram shows something similar to Figure 6 Cross-sectional view,

[0059] Figure 9 It shows something similar to Figure 5 The flux conductor in the schematic three-dimensional diagram is exposed and enlarged in the alternative implementation.

[0060] Figure 10 With similar Figure 6 The view shows that it contains according to Figure 9 The rotating sensor in the second embodiment of the flux conductor.

[0061] Figure 11 It shows according to Figure 9 and Figure 10 In similar Figure 4 The schematic 3D diagram exposes the stator elements and flux conductors of the rotating sensor.

[0062] Figure 12 It shows something similar to Figure 4 The schematic perspective view exposes the stator element and flux conductor of the rotary sensor in the third embodiment.

[0063] Figure 13 It shows the results from the following: Figure 12 An enlarged radial view of the externally observed rotating sensor.

[0064] Figure 14 The internal drivetrain of the steering system with a rotation sensor according to the present invention is shown in an exploded view;

[0065] Figure 14 a shows according to Figure 14 An illustration of a portion of a steering shaft component with an anti-torsion device;

[0066] Figure 15 shows, in an exploded view, the internal drivetrain of a steering system with a rotation sensor according to another embodiment of the invention;

[0067] Figure 15a shows an illustration of a portion of a steering shaft assembly with an anti-torsion device according to Figure 15;

[0068] Figure 16 It shows according to Figure 6 The diagram illustrates flux deflection. Detailed Implementation

[0069] In the various figures, the same parts are always given the same reference numerals, and therefore are usually named or mentioned only once in each case.

[0070] Figure 1 A vehicle steering system 1, designed as an electromechanical power-assisted steering system, is schematically illustrated. The vehicle steering system 1 has a steering column 2 with a support unit 21, which can be attached to a vehicle body (not shown).

[0071] In the steering column 2, the first upper steering shaft component 10 of the steering shaft is mounted in a manner that allows it to rotate about the longitudinal axis L. At the rear end relative to the direction of travel, the steering wheel 12 is attached to the steering shaft component 10 in a manner that allows the driver to input steering torque (manual torque) as a steering command into the upper steering shaft component 10.

[0072] The upper steering shaft component 10 is connected to the second lower steering shaft component 11 via a torsion bar (not shown).

[0073] Steering torque is transmitted to steering pinion 14 via steering shaft assembly 10 and steering shaft assembly 11, and via interconnected cross joint 13. Steering pinion 14 engages in rack 15, which is mounted in a longitudinally displaceable manner. Rack 15 converts the rotation of steering shaft 10 during steering intervention into displacement of tie rod 16, as illustrated by double arrows. Tie rod 16 transmits the predetermined steering intervention as steering lock to the steerable wheels 17 of the vehicle.

[0074] The electric power-assisted support may have a power-assisted actuator 3 or a power-assisted actuator 31, with the power-assisted actuator 3 attached to the steering column 2 and connected to the steering shaft 10, and the power-assisted actuator 31 connected to the steering shaft assembly 11 at the pinion 14. The power-assisted actuator 3 and the power-assisted actuator 31 may be identically constructed. By means of the power-assisted actuator 3 or the power-assisted actuator 31, auxiliary torque can be coupled to the lower steering shaft 11 and / or the steering pinion 14 to assist the driver during steering operations.

[0075] A power-assisted drive 32 can also be provided to introduce auxiliary power for assisting the steering system into the rack 15.

[0076] Conventionally, the power-assisted drive unit 3, 31, or 32 is attached only to one of the three positions shown. The auxiliary torque or power intended to be applied to assist the driver by means of the corresponding power-assisted drive unit 3, 31, or 32 is determined by considering the steering torque determined by the rotation sensor 4 and manually applied by the driver. For this purpose, the rotation sensor 4 has a torque sensor that detects the relative rotation of the steering shaft component 10 and the steering shaft component 11, which depends on the magnitude of the manually applied steering torque. Furthermore, a rotation angle sensor is preferably provided for detecting the angular position of the steering shaft component 10 and / or the steering shaft component 11.

[0077] Figure 14 As shown Figure 1 The internal transmission system of steering system 1 is shown in the diagram. According to... Figure 14 This shows that it is achieved by means of Figure 1 The diagram illustrates an embodiment of a power-assisted drive system 31. An upper steering shaft assembly 10 is connected to a lower steering shaft assembly 11 via a torsion bar 1002 secured by a pin 1003. When torque is introduced into the steering wheel 12, the upper steering shaft assembly 10 rotates, and transmits this torque to the lower steering shaft assembly 11 via the torsion bar 1002. Due to initial resistance to rotation, the torsion bar 1002 itself twists, causing the upper steering shaft assembly 10 to rotate relative to the lower steering shaft assembly by an angle, which is detected accordingly by a rotation sensor 4, whose individual elements are... Figure 14 As shown in the image.

[0078] To limit rotation and prevent mechanical overload of the torsion bar 1002, an anti-torsion device including a first anti-torsion device 1001 is provided, which engages in a second anti-torsion device 1101. A protrusion 10012 of the first anti-torsion device engages with a recess 11011 of the second anti-torsion device with a predetermined angular clearance. Similarly, a protrusion 11012 of the second anti-torsion device engages with a recess 10011 of the first anti-torsion device with a predetermined angular clearance. If the desired angular clearance is achieved, the maximum torsion of the torsion bar 1002 itself is achieved. For better illustration, Figure 14 The second anti-twist device 1101 is illustrated in a different view in figure a.

[0079] The anti-torsion devices 1001 and 1101 have a significant impact on the paths of the interference fluxes S1 and S2. The magnetic fluxes of interference fluxes S1 and S2 are affected by the flux deflection SX by means of the anti-torsion devices 1001 and 1101, and are thus altered.

[0080] Figure 15 shows, for example Figure 1 The internal transmission system of the steering system 1 is illustrated in Figure 15. Figure 15a shows a second anti-torsion device 1101 according to the embodiment of Figure 15 in a different view. According to Figure 15, it is shown that the device is provided by means of... Figure 1 The illustration shows an embodiment of a power-assisted drive 3. This means that in the exemplary embodiment, a gear 9, rotationally symmetrically arranged around a torsion bar, is directly near the rotation sensor 4. In this example, the gear 9, designed as a worm gear, is connected to an electric actuator (not shown) in the steering system via a transmission arrangement (not shown), preferably a worm gear transmission arrangement. Otherwise, these features are similar to those of... Figure 14 The features of the embodiments shown correspond to those of the embodiments, and therefore, repeated descriptions can be omitted.

[0081] However, gear 9 has an even greater influence on the disturbance fluxes S1 and S2, especially when gear 9 has a ferromagnetic core for fastening to one of the two steering shafts. The disturbance fluxes S1 and S2 are affected by and thus altered by an even greater flux deflection SX.

[0082] Rotation sensor 4 is attached between the upper steering shaft component 10 and the lower steering shaft component 11, such as in Figure 2 As can be seen in the enlarged illustration, Figure 2 Shown in enlarged form Figure 1 A schematic perspective view of the steering column 2.

[0083] A magnet 41 is coaxially attached to the steering shaft assembly 10. The magnet 41 may be designed as a ring magnet and is arranged within two annular stator elements 42a and 42b, which are coaxially attached to the second steering shaft assembly 11. The stator elements 42a and 42b have attachment portions 43a and 43b, which are designed in a disk shape and protrude radially outward. The attachment portions 43a and 43b have axial surfaces that are transverse to the axis L on their axially inner sides pointing towards each other and on their axially opposite outer sides.

[0084] Two stator elements 42a and 42b are magnetically connected to two flow conductors 5a and 5b. Figures 4 to 8The two flow conductors 5a and 5b are illustrated in the various views shown.

[0085] Flux conductors 5a and 5b are both designed as integral sheet metal components, and have collecting portions 51a and 51b and compensator portions 52a and 52b, which are connected to each other via mesh connecting portions 53a and 53b. The collecting portions 51a and 51b and the compensator portions 52a and 52b extend parallel to an axial surface perpendicular to the axis, wherein the collecting portions 51a and 51b each extend on a collecting surface, and the compensator portions 52a and 52b each extend correspondingly on a compensator surface.

[0086] Figure 16 The effect of flux deflection SX at collecting sections 51a and 51b on interfering magnetic fluxes S1 and S2 is shown. The accumulation of ferromagnetic components—such as anti-torsion devices 1001, 1101 and possibly additional gears 9, particularly worm gears with metal cores as shown in the example—alteres the ratio of magnetic flux, so that the dimensions of the surfaces of collecting sections 51a and 51b must be adapted to the surfaces of compensator sections 52a and 52b in a certain ratio.

[0087] According to the invention, the collecting surface is greater than or equal to the compensator surface in every case, and preferably conforms to one of the surface ratios described above according to the invention.

[0088] Flux fingers 54a and 54b are attached to compensator portions 52a and 52b, and protrude axially into the intermediate space between attachment portions 43a and 43b, serving as connecting elements. A sensor element 6 for magnetic flux measurement, such as a Hall sensor or GMR sensor, is arranged in the axial air gap between the flux fingers 54a and 54b. Figure 5 As can be seen, for example, two sensor elements 6 can be provided, which are arranged circumferentially between the connecting portions located in the end regions of the flux fingers 54a and 54b that are spaced apart from each other.

[0089] like Figure 3 , Figure 4 , Figure 6 and Figure 8 As shown, the collecting portions 51a and 51b are attached to the inside of the attachment portions 43a and 43b.

[0090] Flux conductors 5a and 5b intersect in the region of connecting portions 53a and 53b between compensator portions 52a and 52b and collecting portions 51a and 51b, such that flux conductors 5a and 5b are axially opposite each other. The axial positions are interchanged, such that the collecting portion 51a of one flux conductor 5a and the compensating portion 52b of the other flux conductor 5b are axially located on one side of the attachment portion 43a where a stator element 42a is arranged, and, axially opposite each other, the collecting portion 51b of the other flux conductor 5b and the compensating portion 52a of the first flux conductor 5a are located on the other side. This forms an arrangement structure that is mirror-symmetric about a mirror plane that is transverse relative to axis L. As seen in the circumferential direction, the X-shaped configuration is formed by the connecting line along the connecting portions 53a and 53b between the collecting portion 51a and the compensator portion 52b, as shown in... Figure 6 and Figure 8 This can be clearly seen in the text.

[0091] exist Figure 3 , Figure 4 , Figure 6 , Figure 10 and Figure 11 In this diagram, the magnetic flux coupled from magnet 41 to one stator element 42a is called the measured flux M1, while the magnetic flux coupled to another stator element 42b is called the measured flux M2. Measured flux M1 and measured flux M2 are represented by solid arrows.

[0092] External interference fields such as Figure 1 , Figure 3 , Figure 4 , Figure 6 , Figure 10 and Figure 11 The outline arrows in the diagram indicate that the external interference field generates magnetic interference flux S1 and magnetic interference flux S2.

[0093] The measurement flux M1, coupled to the stator element 42a by the magnet 41, is conducted via the attachment portion 43a to the collection portion 51a of the flux conductor 5a, and this measurement flux M1 is introduced into the sensor element 6 via the connection element 53a and the compensator element 52a by the flux finger 54a. Therefore, the measurement flux M2 passes through the collection portion 51b of the flux conductor 5b, and reaches the opposite side of the axial direction of the sensor element 6 via the connection element 53b and the compensator element 52b by means of the flux finger 54b. This... Figure 3 and Figure 4 The image is shown in the middle.

[0094] The external magnetic interference field is coupled, at least partially, as interference fluxes S1 and S2 to stator elements 42a and 42b, attachment portions 43a and 43b, and collection portions 51a and 51b, and also to compensator portions 52a and 52b. For example... Figure 6 As schematically shown in the cross-sectional view, in the connection portion of the flux finger 54a axially coupled to the sensor element 6, the measured flux M1 is superimposed by the interference flux S1 and the interference flux S2. Similarly, in the connection portion of the other flux finger 54b, another measured flux M2 is also superimposed by the interference magnetic flux S1 and the interference magnetic flux S2.

[0095] Interference fluxes S1 and S2 from collection sections 51a and 51b and from compensator sections 52a and 52b are coupled to sensor element 6 via flux fingers 54a and 54b with opposite signs. Therefore, the interference fluxes are compensated and ideally cancel each other out, such that only measurement fluxes M1 and M2 are measured by sensor element 6.

[0096] The collecting portions 51a and 51b may have protruding stop portions 55a and 55b, which in this example may protrude axially inward, such as... Figure 5 and Figure 8 As shown, and additionally or alternatively, the stop portions 55a, 55b project axially outward and / or circumferentially. The collecting portions 51a, 51b and the stop portions 55a, 55b may be integrally formed, for example, by bending a metal plate.

[0097] In this example, the compensator portions 52a and 52b may have laterally projecting guide portions 56a and 56b in the circumferential direction. The guide portions 56a and 56b may be designed as integrally formed guide lugs.

[0098] According to the present invention, the collecting surfaces, i.e., the axial surfaces, of the collecting portions 51a and 51b are larger than the compensator surfaces, i.e., the axial surfaces, of the compensator portions 52a and 52b. This surface ratio can preferably be consistent with the range defined above in the description of the present invention.

[0099] The stator elements 42a and 42b, including the attachment portions 43a and 43b, can be formed from a metal sheet with a sheet thickness BS, wherein the sheet thickness BS can be, for example, 0.8 mm.

[0100] The flux conductors 5a and 5b can be integrally formed into sheet-shaped components from a sheet of metal with a sheet thickness BF, wherein the sheet thickness BF can be, for example, 0.8 mm.

[0101] The compensator portions 52a and 52b may have an axial height difference relative to the collecting portions 51a and 51b, the axial height difference approximately corresponding to the metal sheet thickness BF or BS, such that the compensator portions 52a and 52b are substantially flush with the attachment portions 43a and 43b, as shown below. Figure 8 It is illustrated in the diagram.

[0102] The collecting parts 51a and 51b can be located at an axial distance As that is smaller than the axial distance Ak between the compensator parts 52a and 52b.

[0103] The compensator portions 52a, 52b may be located at a radial distance Ra relative to the collecting portions 51a, 51b, the radial distance being related to the radial width Rs of the collecting portions 51a, 51b (as measured in the direction of distance Ra), as defined in the above description of the invention.

[0104] In the region of sensor element 6, flux fingers 54a, 54b have an air gap of axial distance Lu relative to each other, the ratio of which to the sheet thickness BF can preferably be consistent with the range defined above in the description of the invention. Advantageously, the axial height distance between flux fingers 54a, 54b and sensor element 6 is less than the sheet thickness BF.

[0105] The axial distance Ab between the attachment portions 43a and 43b is preferably about 15 times the thickness BS of the metal sheet.

[0106] Figure 9 and Figure 10 With Figure 5 and Figure 6 The same view shows an alternative arrangement of flux conductors 5a and 5b. The connecting portions 53a and 53b are closer to the compensator portions 52a and 52b and intersect each other, whereas in the previously described embodiment, the connecting portions 53a and 53b are closer to the collecting portions 51a and 51b and intersect each other.

[0107] Figures 11 to 13 The improved embodiment of the invention shown has the functional elements of the first embodiment described above, and therefore uses the same reference numerals.

[0108] As in the first embodiment, two sensor elements 6 are provided, which are mounted on a printed circuit board 61 (circuit board 61) and electrically connected.

[0109] In addition to the first embodiment, the compensator portions 52a and 52b each have angled wing portions 57a and 57b, also referred to as winglets, which protrude axially into the intermediate space between the compensator portions 52a and 52b. Figure 13 As can be seen in the radial view, the wing portions 57a and 57b may have dimensions proportional to the sheet thickness BF as defined above in the description of the invention.

[0110] Flux conductors 5a and 5b are introduced into the interior of housing 8 in segments. Sensor element 6 is also housed therein.

[0111] List of reference numerals

[0112] 1. Steering System

[0113] 10. Steering shaft assembly

[0114] 1001 First Anti-Twist Device

[0115] 10011 concave part

[0116] 10012 Protrusion, teeth

[0117] 1002 Torsional Elastic Torsion Bar

[0118] 1003 sales

[0119] 11 Steering Axle Components

[0120] 1101 Second Anti-Twist Device

[0121] 11011 concave part

[0122] 11012 Protrusion, teeth

[0123] 12 Steering Wheel

[0124] 13 Cross joint

[0125] 14 small gears

[0126] 15 racks

[0127] 16 tie rods

[0128] 17 rounds

[0129] 2. Steering column

[0130] 21 Support Unit

[0131] 3.31 Power-assisted drive

[0132] 4. Rotation sensor

[0133] 41. Magnet (ring magnet)

[0134] 42a and 42b stator elements

[0135] Attached sections 43a and 43b

[0136] 5a, 5b Flux Conductors

[0137] Collection sections 51a and 51b

[0138] 52a and 52b compensator sections

[0139] 53a, 53b connection parts

[0140] 54a, 54b Flux Finger

[0141] 55a, 55b stop sections

[0142] 56a, 56b Guiding Sections

[0143] 57a and 57b winglets

[0144] 6. Sensor Components

[0145] 61 Printed Circuit Board

[0146] 8. Housing

[0147] 9 gears

[0148] L-axis

[0149] M1 Measurement Flux

[0150] M2 Measurement Flux

[0151] S1 Interference Flux

[0152] S2 Interference Flux

[0153] SX flux deflection

[0154] BF metal sheet thickness

[0155] BS sheet thickness

[0156] Ab axial distance

[0157] As axial distance

[0158] Ak axial distance

[0159] Ra radial distance

[0160] Rs Radial width

[0161] Lu refers to the axial distance (air gap).

Claims

1. A steering system (1) for a motor vehicle, the steering system (1) having a rotation sensor (4) comprising a magnetic element (41) and two stator elements (42a, 42b), the magnetic element (41) being attached to a steering shaft (10) and rotatable together with the steering shaft about an axis (L), the two stator elements (42a, 42b) being coaxially fixed relative to the steering shaft (10), the two stator elements (42a, 42b) being axially spaced apart from each other and operatively connected to at least one sensor element (6) via two flux conductors (5a, 5b), wherein, The flux conductors (5a, 5b) in each case have a collecting portion (51a, 51b), a connecting portion (53a, 53b), and a compensator portion (52a, 52b), wherein the collecting portion (51a, 51b) is connected to the stator element (42a, 42b) and the collecting portion (51a, 51b) is connected to the compensator portion (52a, 52b) via the connecting portion (53a, 53b), and wherein the sensor element (6) is arranged between the two flux conductors (5a, 5b), characterized in that, The compensator portions (52a, 52b) have a compensator surface that is less than or equal to the collection surface of the collection portions (51a, 51b). The compensator portions (52a, 52b) on the two flux conductors each have angled wing portions (57a, 57b) that protrude in the axial direction into the intermediate space between the compensator portions (52a, 52b).

2. The steering system according to claim 1, characterized in that, The surface ratio of the collecting surface to the compensator surface is between 1 and 4.

3. The steering system according to claim 2, characterized in that, The surface ratio of the collecting surface to the compensator surface is between 1 and 3.

4. The steering system according to claim 2, characterized in that, The surface ratio of the collecting surface to the compensator surface is between 1 and 2.

5. The steering system according to claim 2, characterized in that, The surface ratio of the collecting surface to the compensator surface is between 1.5 and 2.

6. The steering system according to claim 2, characterized in that, The surface ratio of the collecting surface to the compensator surface is between 1.5 and 1.

75.

7. The steering system according to claim 2, characterized in that, The surface ratio of the collecting surface to the compensator surface is 1.

75.

8. The steering system according to any one of claims 1-7, characterized in that, The flux conductors (5a, 5b) are both designed as a single metal sheet forming component.

9. The steering system according to any one of claims 1-7, characterized in that, The flux conductors (5a, 5b) intersect in the region of the connecting portion (53a, 53b) between the compensator portion (52a, 52b) and the collecting portion (51a, 51b) such that the compensator portion (52a, 52b) and the collecting portion (51a, 51b) are axially opposite each other.

10. The steering system according to any one of claims 1-7, characterized in that, The compensator surface and the collecting surface of the flux conductors (5a, 5b) are substantially parallel to each other and parallel to the attachment portions (43a, 43b) of the stator elements (42a, 42b) connected to the collecting portions (51a, 51b).

11. The steering system according to any one of claims 1-7, characterized in that, The collecting portions (51a, 51b) are attached to the axially opposite inner sides of the stator elements (42a, 42b).

12. The steering system according to any one of claims 1-7, characterized in that, The axial distance (Ab) between the collecting portions (51a, 51b) is less than the axial distance (Ak) between the compensator portions (52a, 52b).

13. The steering system according to claim 10, characterized in that, The compensator portions (52a, 52b) are aligned flush with the attachment portions (43a, 43b) of the stator elements (42a, 42b).

14. The steering system according to any one of claims 1-7, characterized in that, The compensator portions (52a, 52b) are connected to the coupling portion, which has a coupling surface facing the sensor element (6).

15. The steering system according to any one of claims 1-7, characterized in that, At least two sensor elements (6) are set apart from each other.

16. The steering system according to any one of claims 1-7, characterized in that, The flux conductors (5a, 5b) and the sensor element (6) are arranged in the housing (8).

17. The steering system according to any one of claims 1-7, characterized in that, The compensator portions (52a, 52b) and / or the collecting portions (51a, 51b) have guiding portions (56a, 56b).

18. The steering system according to any one of claims 1-7, characterized in that, The collecting portion (51a) of one flux conductor (5a) and the compensator portion (52b) of another flux conductor (5b) are separated by a radial distance (Ra) from each other, the ratio of the radial distance (Ra) to the radial width (Rs) of the collecting portion (51b) of the other flux conductor (5b) being between 0.5 and 2.

19. The steering system according to claim 18, characterized in that, The ratio of the radial distance (Ra) to the radial width (Rs) of the collection portion (51b) of the other flux conductor (5b) is between 0.75 and 1.

5.

20. The steering system according to claim 18, characterized in that, The ratio of the radial distance (Ra) to the radial width (Rs) of the collection portion (51b) of the other flux conductor (5b) is between 0.75 and 1.

25.

21. The steering system according to claim 18, characterized in that, The ratio of the radial distance (Ra) to the radial width (Rs) of the collection portion (51b) of the other flux conductor (5b) is between 0.8 and 1.

2.

22. The steering system according to claim 18, characterized in that, The ratio of the radial distance (Ra) to the radial width (Rs) of the collection portion (51b) of the other flux conductor (5b) is 1.

23. The steering system according to claim 18, characterized in that, The collecting portion (51a) of one flux conductor (5a) has an axial height difference relative to the compensator portion (52b) of the other flux conductor (5b) such that the ratio of the axial height difference to the axial thickness (BF) of the collecting portion (51a) is between 0.5 and 2.

24. The steering system according to claim 23, characterized in that, The ratio of the axial height difference to the axial thickness (BF) of the collecting portion (51a) is between 0.75 and 1.

5.

25. The steering system according to claim 23, characterized in that, The ratio of the axial height difference to the axial thickness (BF) of the collecting portion (51a) is between 0.75 and 1.

25.

26. The steering system according to claim 23, characterized in that, The ratio of the axial height difference to the axial thickness (BF) of the collecting portion (51a) is between 0.8 and 1.

2.

27. The steering system according to claim 23, characterized in that, The ratio of the axial height difference to the axial thickness (BF) of the collecting portion (51a) is 1.

28. The steering system according to any one of claims 1-7, characterized in that, The collecting portion (51a) of one flux conductor (5a) has an axial height difference relative to the compensator portion (52a) of the same flux conductor (5a) such that the ratio of the axial height difference to the axial height difference between the compensator portions (52a, 52b) of the two flux conductors (5a, 5b) is between 0.75 and 2.

2.

29. The steering system according to claim 28, characterized in that, The collecting portion (51a) of one flux conductor (5a) has an axial height difference relative to the compensator portion (52a) of the same flux conductor (5a) such that the ratio of the axial height difference to the axial height difference between the compensator portions (52a, 52b) of the two flux conductors (5a, 5b) is between 0.85 and 1.

2.

30. The steering system according to claim 28, characterized in that, The collecting portion (51a) of one flux conductor (5a) has an axial height difference relative to the compensator portion (52a) of the same flux conductor (5a) such that the ratio of the axial height difference to the axial height difference between the compensator portions (52a, 52b) of the two flux conductors (5a, 5b) is between 0.9 and 1.

15.

31. The steering system according to claim 28, characterized in that, The collecting portion (51a) of one flux conductor (5a) has an axial height difference relative to the compensator portion (52a) of the same flux conductor (5a) such that the ratio of the axial height difference to the axial height difference between the compensator portions (52a, 52b) of the two flux conductors (5a, 5b) is 1.

125.

32. The steering system according to any one of claims 1-7, characterized in that, In the region where the sensor element (6) is arranged, the two flux conductors (5a, 5b) have an axial height distance (Lu) ranging from 1.8 to 2.2 times the axial thickness (BF) of the flux conductors (5a, 5b).

33. The steering system according to any one of claims 1-7, characterized in that, The axial height distance between the flux conductors (5a, 5b) and the sensor element (6) is less than the axial thickness (BF) of the flux conductors (5a, 5b).

Images