CN104976949B

CN104976949B - Measuring device for contactless rotation angle detection

Info

Publication number: CN104976949B
Application number: CN201510173996.0A
Authority: CN
Inventors: T·克洛茨比歇尔; J·梅斯; N·朗; T·沟边
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-04-14
Filing date: 2015-04-13
Publication date: 2020-09-29
Anticipated expiration: 2035-04-13
Also published as: FR3019892B1; KR102383206B1; KR20150118551A; DE102014207139A1; CN104976949A; FR3019892A1

Abstract

The invention provides a measuring device for contactless determination of a rotation angle. The measuring device has a first member having a magnet. The measuring device has a second component with a magnetically sensitive element. The first and second members are rotatably supported relative to each other about a common axis of rotation. The magnetically active element is embodied to determine a rotation angle value of the first component with respect to the second component from the magnetic field of the magnet. The magnet has a first section along the axis of rotation having a first outer diameter in a plane transverse to the axis of rotation. The magnet has, along the axis of rotation, a second section connected to the first section, which has a second outer diameter in a plane transverse to the axis of rotation, the second section being located between the first section and the magnetically active element, as seen along the axis of rotation. The first outer diameter is larger than the second outer diameter, in particular the second outer diameter is between 30% and 70% of the first outer diameter. The invention also relates to a regulating system with the measuring device and a method for producing the measuring device.

Description

Measuring device for contactless rotation angle detection

Technical Field

The invention relates to a measuring device for contactless detection of a rotation angle.

Background

Rotation angle measurements have to be carried out in a number of technical fields. This can be done, for example, by means of magnetic field sensors, which detect the position of the permanent magnet. The permanent magnet can be fixed in a rotationally fixed manner on the rotary element and allows a contactless rotation angle detection. A contactless rotation angle sensor is known, for example, from DE 102007016133 a 1.

Disclosure of Invention

The invention proceeds from the recognition that the magnetic field strength of the permanent magnet must be sufficiently high in order to be able to achieve an optimum rotational angular resolution of the sensor. Furthermore, high magnetic field strengths can positively affect the sensor's insensitivity to external magnetic fields and to aging.

Furthermore, the magnetic field of the permanent magnet must be sufficiently homogeneous in order to compensate for tolerances of the new components or tolerances occurring during operation. In this case, for example, a displacement of the axis of rotation due to wear or to mechanical play can lead to the occurrence of operational tolerances.

In order to ensure a sufficient magnetic field strength and homogeneity of the permanent magnet, magnets with a large extension may be applied. However, these magnets require a large installation space, which can be limited, in particular, in motor vehicles. Rare earth magnets such as neodymium magnets having a high remanence may be applied in applications with limited structural space. However, rare earth magnets can involve high costs.

There may therefore be a need for an improved measuring device, a corresponding adjusting system and a method for producing a measuring device, which in particular make it possible to provide a cost-effective measurement accuracy in a limited installation space that remains constantly high when determining a rotation angle, for example over the lifetime. This means that the angular error is minimized, for example, with a reduced installation space, for example, in that the magnetic field strength at the location of the magnet sensor or the magnetically sensitive element or the homogeneity of the magnetic field at the location of its detection is increased compared to conventional configurations.

Advantages of the invention

This need may be met by the subject matter of the present invention. The invention also proposes advantageous embodiments.

The features, details and possible advantages of the device according to embodiments of the invention are discussed in detail below.

According to a first aspect of the invention, a measuring device for the contactless determination of a rotation angle is proposed. The measuring device has a first component with a magnet, for example a neodymium magnet, but preferably a cost-effective ferrite magnet. Furthermore, the measuring device has a second component which has a magnetically sensitive element. The first and second members are rotatably supported relative to each other about a common axis of rotation. The magnetically active element is embodied here in such a way that a rotation angle value or a rotation angle of the first component relative to the second component is determined as a function of the magnetic field of the magnet. The magnets have a first section along a common axis of rotation, the first section having a first outer diameter in a plane transverse to the axis of rotation. Furthermore, the magnet has a second section connected to the first section along the axis of rotation, which second section has a second outer diameter in a plane transverse to the axis of rotation, wherein the second section is located between the first section and the magnetically active element, as viewed along the axis of rotation. The first outer diameter is greater than the second outer diameter, in particular the second outer diameter is between 30% and 70% of the first outer diameter.

In other words, the concept of the invention is based on: the second section is configured relative to the first section as an overhang that protrudes beyond the first section. This advantageously results in comparison with the prior art: the magnetic field required for the contactless rotation angle determination is more strongly formed at the detected position and is made more uniform and the magnet is simultaneously formed with a smaller transverse dimension in a plane extending transversely to the axis of rotation (XY plane) and a smaller dimension in the direction of the axis of rotation (Z direction). The constructive measure, i.e. the second diameter of the overhanging second section is designed to be smaller than the first diameter of the first section, causes the magnetic field lines to be concentrated and homogenized at the location detected by the magnetically sensitive element or the magnet sensor. This makes it possible to reduce the installation space of the measuring device with the same magnet material and/or to use intrinsically weaker, but more cost-effective magnet materials, such as ferrite magnets, instead of rare earth magnets and at the same time to reduce the angle error. In this way, the manufacturing costs of the measuring device can be saved while maintaining the required homogeneous magnetic field and the measuring device can be used in a smaller installation space.

The measuring device can be used, for example, in a motor vehicle, for example a hybrid or electric vehicle. The measuring device can be used in all systems in the vehicle sector, in which the angle of rotation is measured. For example, the measuring device can be used on a throttle sensor, an accelerator pedal value sensor, a body elasticity sensor or an angle sensor of a wiper drive.

The first member may be a rotating member, such as a rotor. At least one magnet is disposed on the first member. The magnet is connected in a rotationally fixed manner to the first component. The magnet is embodied here as a permanent magnet. Furthermore, the magnet can be partially injection molded, for example.

The second component may be, for example, a stationary component, such as a stator. The magnetically active element is connected to the second component in a rotationally fixed manner. The magnetically sensitive element can be, for example, a hall sensor or a magnetoresistive sensor. For example, the magnetically susceptible element may output a signal depending on the magnetic field of the magnet, in particular depending on the direction and strength of the magnetic field, said signal representing the value of the angle of rotation of the first component with respect to the second component.

If the magnetically sensitive element is embodied, for example, as a hall sensor, the hall sensor can have a current-carrying semiconductor foil which is penetrated, for example, perpendicularly by the magnetic field of the magnet. A voltage proportional to the magnetic field strength can be tapped off transversely to the current direction at the semiconductor foil. The magnetically sensitive element may have, for example, silicon. In this case, the magnetically sensitive element can be integrated with a control unit or with signal processing electronics.

The magnet can be embodied, for example, as a cylindrical disk magnet with a centrally arranged projection on the first section serving as the magnet base body, which projection represents the second section. Ferrite is used here, for example, as a material for the magnets. In particular barium ferrite (BaFe)₁₂O₁₉) Or strontium ferrite (SrFe)₁₂O₁₉) Can be used as a magnet material. The material walls, for example rare earth magnets, are more cost-effective and ensure the same magnetic field homogeneity as rare earth magnets of the same size due to the corresponding geometry. However, the magnet may also be configured as a rare earth magnet, for example a neodymium magnet.

According to an embodiment of the invention, the first section has a first height along the rotation axis and the second section has a second height along the rotation axis. The second height is here between 15% and 75%, preferably between 35% and 70% and very particularly preferably between 55% and 65% of the first height. This advantageously results in a particularly good magnetic field strength and a particularly good homogeneity of the magnetic field lines at the location of the magnetic sensor or of the magnetically sensitive element, in particular parallel to the XY plane. This advantageously minimizes the measurement error of the angle of rotation and thus makes it possible to construct magnets with smaller dimensions than in conventional constructions, i.e. magnets of the same strength and uniform design without excess. For example, the total height of the magnet (consisting of the first section and the second section) may be between 2.3 mm and 5 mm. Preferably, the total height of the first section is between 2.0 mm and 3 mm, very particularly preferably 2.5 mm. The height of the second section can be between 0.3 mm and 2.25 mm, preferably between 0.5 mm and 1.8 mm and very particularly preferably between 0.8 mm and 1.5 mm. For example, the height of the first section is 2.5 mm, while the height of the second section is between 0.27 mm and 1.88 mm.

In one embodiment, the second section can be configured cylindrically and/or coaxially to the axis of rotation. The magnet can thus be produced particularly simply and the magnetic field is particularly strong and homogeneous at the location of the magnet sensor or the magnetically sensitive element. In addition, the magnet shaped in this way can be assembled in a simplified manner, since it can be designed rotationally symmetrically about the axis of rotation and therefore there is no risk that it will undesirably get into contact with components of the measuring device during the rotational installation. The magnet may have the shape of a two-stage circular wedding cake, for example, wherein the second cylindrical section of the overhang is formed on the first section of the cylindrical structure. Without limiting its function, it is also possible here to form small projections or notches on the outer side of such a magnet in order to secure the magnet in the housing in a rotationally and/or non-releasable manner, for example by means of an injection molding process. Such protrusions or notches should not be considered to impair the cylindrical shape in the sense of this application, in particular if the volume of such protrusions or notches does not constitute more than 5% of the total magnet volume.

According to one embodiment of the invention, the second section has an end side facing the magnetically active element. A groove extending into the interior of the second section is provided on the end face of the second section. The grooves are designed here, for example, as symmetrical recesses. The magnet can have, in particular, a circular recess in a plane parallel to the magnetically active element, in an XY plane extending transversely to the axis of rotation. The magnetic field thereby becomes particularly strong and uniform at the location of the magnetic sensor or the magnetically sensitive element.

The recess can be embodied, for example, as a blind hole. Here, the grooves ensure a uniform magnetic field in the XY direction. In other words, the magnetic field lines in the region of the recess run as parallel as possible to one another between the magnet and the magnetically active element and at the same distance from one another. The magnetic field lines run here as parallel as possible to the surface of the magnetically active element. In an alternative embodiment, the magnetic field lines may run perpendicular to the surface of the magnetically active element. The magnetically active element is implemented accordingly here.

According to a further embodiment, the groove depth of the groove is between 15% and 75%, in particular between 35% and 70%, of the second height of the second section. Thus, the groove may have a groove depth of between 0.27 mm and 1.35 mm at a second height of 1.8 mm beyond the extension or second section. Particularly preferably, the groove can have a groove depth of between 0.3 mm and 1.2 mm, in particular between 0.3 mm and 0.6 mm. The groove depth can be measured parallel to the longitudinal axis or to the axis of rotation of the magnet in the Z direction. The magnetic field thereby becomes particularly strong and uniform at the location of the magnetic sensor or the magnetically sensitive element.

The depth of the recess, i.e. the dimension in the extension perpendicular to the surface of the magnetically active element, also referred to as the Z-direction, is here as uniform as possible. That is, the groove depth of the groove may be between 0.3 mm and 1.2 mm over substantially the entire face of the groove. Alternatively, the grooves may correspond to a body of revolution of a parabola, or the grooves may be implemented in two stages. That is, the groove may have a first region having a first groove depth and a second region having a second groove depth along the Z-direction. The second region can be arranged coaxially around the first region. Further, the first groove depth may be greater than the second groove depth, depending on the magnitude. The recess can be designed in particular in several stages. The stepped configuration of the groove can be realized more simply in terms of manufacturing technology than, for example, a parabolic recess.

Furthermore, a homogeneous magnetic field over the entire surface of the magnetically active element can be ensured even with a large extension or size of the magnetically active element due to the two-stage or multi-stage configuration of the recesses.

According to another embodiment, the groove may have a groove diameter in a plane transverse to the axis of rotation, i.e. the XY plane, and the magnetically sensitive element may have a diameter in a plane transverse to the axis of rotation, i.e. the XY plane. The diameter of the recess is greater than the diameter of the magnetically active element. This advantageously results in: the uniform and strong magnetic field area is larger in its size than the magnetically sensitive element. A particularly homogeneous magnetic field can be generated in the region of the magnetically active element by the configuration of the recess having a larger dimension than the surface of the magnetically active element. The diameter of the recess is determined in the XY plane in the direction of the recess, i.e. parallel to the surface of the magnetically active element.

For example, the magnets may have an overall diameter of 14 mm to 18 mm, preferably 16 mm. The diameter of the recess can be, for example, between 2 mm and 5 mm, preferably between 2.25 mm and 4 mm. The magnetically active element can be embodied here, for example, as a rectangle and has, for example, an edge length of between 1 mm and 2 mm.

According to another embodiment of the invention, an air gap is provided between the magnetically active element and the magnet. Depending on the application of the measuring device, the air gap can have a width of between 0.5 mm and 4 mm, preferably between 1.5 mm and 3.2 mm. That is to say, the magnetically active element is not arranged in the groove, but is spaced apart from the groove and also from the end face of the second section, i.e. the overhang, parallel to the axis of rotation in the Z direction.

According to a further embodiment of the invention, the magnet is connected with the first member in a rotationally fixed manner; while the magnetically active element is connected to the second component in a rotationally fixed manner. The first component can be embodied as a rotor and the second component as a stator. Alternatively, the first component may be embodied as a stator and the second component as a rotor.

According to a second aspect of the invention, an adjustment system for a motor vehicle is proposed. The adjusting system has an adjusting unit and the measuring device. The measuring device is designed to transmit or transmit the determined angle of rotation value to the control unit. Furthermore, the adjustment unit is designed to readjust the angle of rotation on the basis of the determined angle of rotation value. The control unit can be integrated into a chip, for example, on which the magnetically sensitive element is provided.

According to one exemplary embodiment of the present invention, the control system is designed as a throttle sensor, an accelerator pedal value sensor in a pedal module, a body elasticity sensor or an angle sensor of a wiper.

According to a third aspect of the invention, a method for manufacturing the measuring device is proposed. The method has the following steps: providing a first member; connecting a magnet, such as a ferrite magnet, to the first component in a rotationally fixed manner; providing a second member; connecting the magnetic sensitive element to the second component in a rotationally fixed manner; the first and second members are rotatably mounted about a common axis of rotation in such a way that they can rotate relative to one another. The magnetically active element is embodied here in such a way that a rotation angle value or a rotation angle of the first component relative to the second component is determined as a function of the magnetic field of the magnet. The magnet has a first section along the axis of rotation, which has a first outer diameter in a plane transverse to the axis of rotation. The magnet has a second section connected to the first section along the axis of rotation, the second section having a second outer diameter in a plane transverse to the axis of rotation, wherein the second section is located between the first section and the magnetically active element as viewed along the axis of rotation. The first outer diameter is greater than the second outer diameter, which is in particular between 30% and 70% of the first outer diameter.

The individual steps of the method may be performed in a variable order.

Drawings

Further features and advantages of the invention will become apparent to the person skilled in the art from the following description of exemplary embodiments with reference to the attached drawings, which, however, should not be construed as limiting the invention. Wherein:

FIG. 1 shows a perspective view of a measurement device according to one embodiment of the present invention;

fig. 2 shows a cross section of a magnet and of a magnetically active element optimized according to the invention;

FIG. 3 shows a cross-section of a measuring device according to the invention;

4a-4d show an angular error and a magnetic field strength of the measuring device according to the air gap between the magnet and the magnetically active element for different radial distances of the magnetically active element from the axis of rotation, by way of example;

fig. 5a shows a graph of the magnetic field lines at the location of the magnetically sensitive element for a magnet without form optimization;

fig. 5b shows a graph of the magnetic field lines at the location of the magnetically active element for a magnet according to the invention.

All figures are merely schematic representations of an apparatus according to an embodiment of the invention or of its component parts. In particular, the pitch and size relationships are not reproduced to scale in the drawings. Corresponding elements in different figures are provided with the same reference numerals.

Detailed Description

Fig. 1 shows a perspective view of a measuring device 1. The measuring device 1 has a first component 3 and a second component 5. The first member 3 may be, for example, a rotor, and the second member 5 may be a stator. Likewise, the second component 5 may also be a rotor, while the first component 3 may be a stator. For example, the first component 3 and the second component 5 can be part of an actuating system 27, in particular a throttle sensor, an accelerator pedal value sensor, a body elasticity sensor or an angle sensor for a wiper of a motor vehicle. The measuring device 1 can therefore be used, for example, on an electric throttle valve DV-E, on an accelerator pedal module APM or in a general-purpose actuator GPA.

A magnet 7 is arranged on the first component 3 in a rotationally fixed manner. A magnetically sensitive element 9, in particular a hall sensor, is provided on the second component 5 and is connected to the second component 5 in a rotationally fixed manner. As shown in fig. 3, the magnetically active element 9 may be arranged, for example, on a printed circuit board 33. The first member 3 can be rotated about the second member 5 about the rotation axis 11 by a rotation angle alpha. The magnetically sensitive element 9 is traversed by field lines of the magnetic field of the magnet 7. The magnetically active element 9 is embodied here to determine the angle of rotation of the first component 3 relative to the second component 5 as a function of the direction and intensity of the magnetic field. The measuring device 1 and in particular the magnetically sensitive element 9 can transmit the determined rotation angle value to the regulating unit 29. The actuating unit 29 can be arranged here together with the magnetically active element 9 on a printed circuit board 33. This is illustrated, for example, in the diagram of fig. 3. Alternatively, the adjusting unit 29 is arranged outside the measuring device 1, as shown in fig. 1. Furthermore, the adjustment unit 29 can be functionally connected to the first component 3 and readjust the angle of rotation α based on the determined angle of rotation value. To better compare the different figures, a coordinate system is drawn. The X-axis is denoted 35, the Y-axis 37 and the Z-axis 39. The Z axis 39 runs parallel to the axis of rotation 11. A plane perpendicular to the axis of rotation is spanned by the X-axis 35 and the Y-axis 37. The surface of the magnetically active element 9 is located here, for example, in a plane spanned by the X axis 35 and the Y axis 37, i.e. the XY plane.

In fig. 2 a cross section of a perspective view of an embodiment of the magnet 7 is shown. The magnets are, for example, ferrite magnets. The magnet, viewed along the axis of rotation 11, has a magnet base body 8 which, in a plane transverse to the axis of rotation 11, i.e. the XY plane, has a first portion 80 having a first outer diameter D1. The first section 80 may be configured as a cylindrical element and as a rotational symmetry with respect to the rotational axis 11. The first section 80 has a first height h1 along the axis of rotation 11, i.e. in the z direction 39.

A second section 82, which has a second outer diameter D2 in a plane transverse to the axis of rotation 11 and a second height h2, viewed along the axis of rotation 11, is connected to the first section 80, viewed along the axis of rotation 11. The second section 82 can be cylindrical in design. The second outer diameter D2 is smaller than the first outer diameter D1. In other words, the second portion 82 forms the projection 15 relative to the first portion 80 or relative to the magnet base body 8. The second section has an end face 16 which faces the magnetically active element 9. The second portion 82 can be arranged completely between the first portion 80 and the magnetic sensitive element 9.

The groove 17 can be located on or in the end face 16 of the second portion 82, which groove projects into the interior of the second portion 82, for example coaxially with the second portion 82, and has a groove diameter D3 and a groove depth h 3. The groove diameter D3 may be detected as the inner diameter of the groove.

An air gap 25 may be located between the end face 16 of the second section and the magnetically active element 9. The air gap 25 may have a gap width, viewed along the axis of rotation 11, of between 0.5 mm and 4 mm, preferably between 0.7 mm and 2.2 mm.

The recess 17 may be cylindrical in form, in the form of a blind hole with a wall which runs parallel to the axis of rotation 11. The groove 17 may have the same groove diameter D3 throughout its depth extension in the Z-direction 39. The recess 17 may also have other shapes, such as a parabolic shape. The recess 17 can also be designed in multiple stages, for example in two or three stages in the form of a continuous blind hole with a diameter which decreases in a plane transverse to the axis of rotation 11. The groove depth h3 can be smaller than the second height h2 of the second portion 82, so that the groove 17 does not project into the first portion 80 or the magnet base body 8, but is arranged completely in the second portion 82. The groove depth h3 and the second height h2 of the second portion 82 are adjusted in such a way that the angle error is minimized in the region of the magnetically active element 9. In particular the recess 17 has a smaller depth than the air gap 25.

The homogeneity of the magnetic field in the air gap 25 can be further improved by a two-stage or multi-stage configuration of the recesses 15.

For example, the first section 80 has a first outer diameter D1 of 16 millimeters and a first height h1 of 2.5 millimeters. The second section 82 has, for example, a second outer diameter D2 of 6.6 mm and a second height h2 of between 0.5 mm and 1.8 mm and is configured coaxially with the first section 80. The groove 17 has, for example, a groove diameter D3 of between 2.25 mm and 4 mm and a depth h3 of between 0.3 mm and 1.2 mm, wherein the groove depth h3 may be smaller than the second height h2 and may be smaller than the gap width of the air gap 25. By means of such a geometry, a very homogeneous and sufficiently strong magnetic field can be achieved in the working region of the magnetic sensitive element, which magnetic field penetrates the magnetic sensitive element 9 as horizontally as possible. The working region can extend in this case along the axis of rotation, i.e. in the Z direction 39, at a distance of between approximately 0.7 mm and 3 mm. The working region can extend with respect to the axis of rotation 11 up to a radial distance of 1.25 mm from the axis of rotation 11 in the XY plane, it being implied that the axis of rotation 11 extends through the center of the magnet 7.

As shown in fig. 2, the groove diameter D3 of the groove 17 is greater than the diameter D4 of the magnetically active element 9.

Fig. 3 shows a cross section of the measuring device 1 shown in fig. 1. As shown in fig. 3, the magnet 7 may be fixed to the first member 3 by means of a magnet holding device 31. The magnet holder 31 can be, for example, plastic that is injection-molded onto the magnet. In order to better fix the magnet 7 in the magnet holding device 31, a plurality of holding elements 8a protruding radially from the magnet base body 8 can be arranged around the first outer diameter D1 of the first section 80 or of the magnet base body 8. In the case of injection molding the magnet 7 in plastic, the magnet 7 is in this way better gripped in the plastic. The retaining element 8a is counted as a first outer diameter D1.

The orientation of the cross-sectional view in fig. 3 is rotated relative to the view in fig. 1. The magnet 7 is preferably embodied here as a ferrite magnet. The function of the ferrite magnet 7 is to generate a magnetic field in the measuring region of the magnetically sensitive element 9. The minimum and maximum permissible magnetic fields caused by the variation of the air gap between the magnet 7 and the magnetically active element 9 are given by the specifications of the magnetically active element 9. The magnetic field allowed is achieved by the geometric design of the magnet 7 and, in addition, by the diameter of the magnet and its height.

An angle error can be caused by inhomogeneities in the magnetic field 13 in the measuring region of the magnetically sensitive element 9. The maximum permissible angle error is given by the respective application. The inhomogeneity of the magnetic field 13 is reduced by providing the first portion 80 with a second portion 82 configured as an overhang 15. A further improvement in the homogeneity and strength of the magnetic field at the location of the magnetically active element 9 can be brought about by providing a recess 15 on or at the side of the magnet 7 facing the magnetically active element 9. The groove 15 is designed here as a recess in or on the end face 16 of the second section 82.

Fig. 4a and 4c show the angular error of the measuring device 1 in degrees as a function of the width of the air gap 25 in millimeters between the magnet 7 and the magnetically active element 9 for two different transverse spacings of the magnetically active element 9 from the axis of rotation 11. The width of the air gap is recorded here in millimeters on the X-axis. The angle error in degrees is recorded on the Y-axis, wherein the dashed line at 0.8 ° parallel to the X-axis shows the maximum permissible angle error.

Fig. 4b and 4d show the maximum and minimum magnetic field strength as a function of the width of the air gap 25 for two differently sized position regions transverse to the axis of rotation 11, in which the magnetically active element 9 can be arranged. The position regions extending transversely to the axis of rotation are the same for fig. 4a and 4b and for fig. 4c and 4d, respectively. The curves of the maximum field strength describe the maximum field strength values which the magnetically susceptible element 9 experiences in the movement transversely to the axis of rotation 11 over the entire position range for a defined width (indicated on the X axis) of the air gap 25. In contrast, the curve of the minimum field strength describes the minimum of the movement of the magnetically active element 9 in the region of the position transversely to the axis of rotation 11. In fig. 4d, the measuring or positioning area transverse to the axis of rotation 11, in which the magnetically active element 9 can be moved, is larger than in fig. 4 b. The curve of the maximum field strength therefore has almost the same course in both figures, whereas the curve of the minimum field strength is clearly different in both figures, since the field strength generally decreases at the edge of the region of the location radially outside with respect to the axis of rotation 11. The two solid lines parallel to the X-axis illustrate the minimum permissible lower or upper boundary values for the magnetic field strength, i.e. in the figure at about 25mT and at about 63 mT.

It is clear from the figures that when the magnetically susceptible elements 9 are moved radially outwards up to 1.25 mm from the axis of rotation 11, the strength and homogeneity of the magnetic field meet the specifications with an air gap width of between about 0.8 mm and about 1.2 mm at the chosen geometry of the magnet. Fig. 4a and 4c show that the angle error is approximately 0.1 ° for an air gap width, i.e. a spacing of approximately 1.6 mm between the magnetically active element 9 and the end face 16 of the second portion 82, and that the maximum and minimum field strength values in the region of the position of the magnetically active element 9 are at the same time centered within a defined range for the air gap width.

Fig. 5a and 5b show different changes of the magnetic field 13 or of the magnetic field lines of the magnet 7 in the air gap 25 in different configurations of the magnet 7. Fig. 5a shows a commercially available magnet 7' without a second section 82 formed as an extension 15. The commercially available magnet 7' is composed only of a magnet base body 8. In the upper region of fig. 5a, a top view of a commercially available magnet 7' is shown. A cross section of a commercially available magnet 7' is shown in the lower region of fig. 5 a. The magnetic field lines 13' run non-parallel in the measuring region of the magnetically active element 9. Fig. 5b shows the course of the field lines of the magnetic field 13 of the magnet 7, which has a first section 80 and a second section 82, which is formed as an overhang 15 with respect to the first section 80 and is connected to the first section 80. The second section 82 has a groove 17. By means of the design of the magnet 7 in a configuration selected in this way, the field lines of the magnetic field 13 run in the air gap 25 or at the magnetically active element 9 as parallel as possible to the surface of the magnetically active element 9 and have a sufficient field strength there, which can lie in the region between 15mT (millitesla) and 75mT, in other embodiments up to 200mT or even up to 500 mT.

It should be noted later that terms like "having" or the like do not exclude that further elements or steps may be present. Furthermore, it should be noted that "a" or "an" does not exclude a plurality. Furthermore, the described features can be combined with one another in any desired manner in connection with different embodiments.

Claims

1. A measuring device (1) for the contactless determination of a rotation angle (α), the measuring device (1) having: a first component (3) having a magnet (7) which is embodied as a permanent magnet and has an N pole and an S pole in a horizontal direction, and a second component (5) having a magnetically active element (9), wherein the first component (3) and the second component (5) are mounted rotatably relative to one another about a common axis of rotation (11), wherein the magnetically active element (9) is embodied to determine a rotation angle value of the first component (3) relative to the second component (5) as a function of a magnetic field (13) of the magnet (7), wherein the magnet (7) has a first section (80) along the axis of rotation (11) which has a first outer diameter (D1) in a plane transverse to the axis of rotation (11), wherein the magnet (7) has a second section (82) along the axis of rotation (11) which is connected to the first section (80), the second section has a second outer diameter (D2) in a plane transverse to the axis of rotation (11), wherein the second section (82) is located between the first section (80) and the magnetically active element (9) as viewed along the axis of rotation (11), and the magnetically active element (9) is opposite an end face (16) of the second section (82), wherein the first outer diameter (D1) is greater than the second outer diameter (D2), and the second outer diameter (D2) is between 30% and 70% of the first outer diameter (D1).

2. The measurement device according to claim 1, wherein the first section (80) has a first height (h1) along the rotation axis (11) and the second section (82) has a second height (h2) along the rotation axis (11), wherein the second height (h2) is between 40% and 75% of the first height (h 1).

3. Measuring device according to one of the preceding claims, wherein the second section (82) is configured cylindrically and/or the second section (82) is configured coaxially to the axis of rotation (11).

4. Measuring device according to claim 1 or 2, wherein the second section (82) has an end side (16) facing the magnetically susceptible element (9); wherein a groove (17) extending into the interior of the second section (82) is provided on the end face (16) of the second section (82).

5. The measuring device (1) according to claim 4, wherein the groove depth (h3) of the groove (17) is between 15% and 75% of the second height (h2) of the second section (82).

6. The measuring device (1) according to claim 4, wherein the groove (17) has a groove diameter (D3) in a plane transverse to the axis of rotation (11); wherein the magnetically active element (9) has a diameter (D4) in a plane transverse to the axis of rotation (11); wherein the groove diameter (D3) is larger than the diameter (D4) of the magnetically active element (9).

7. Measuring device (1) according to claim 1 or 2, wherein an air gap (25) is provided between the magnetically susceptible element (9) and the magnet (7), wherein the air gap (25) has a width (h4) of between 0.5 mm and 4 mm, viewed along the axis of rotation (11).

8. The measuring device (1) according to claim 1 or 2, wherein the magnet (7) is connected with the first member (3) in a rotationally fixed manner; wherein the magnetically active element (9) is connected to the second component (5) in a rotationally fixed manner; the first component (3) is embodied as a rotor and the second component (5) is embodied as a stator; alternatively, the first component (3) is embodied as a stator and the second component (5) as a rotor.

9. The measuring device (1) according to claim 2, wherein the second height (h2) is between 55% and 70% of the first height (h 1).

10. The measuring device (1) according to claim 5, wherein the groove depth (h3) of the groove (17) is between 35% and 70% of the second height (h2) of the second section (82).

11. The measurement device (1) according to claim 7, wherein the air gap (25) has a width (h4) of between 1.5 mm and 3.2 mm, viewed along the axis of rotation (11).

12. A regulating system (27) for a motor vehicle, the regulating system (27) having a measuring device (1) according to one of claims 1 to 11 and a regulating unit (29); wherein the measuring device (1) is designed to transmit the determined angle of rotation to the control unit (29); wherein the adjusting unit (29) is designed to readjust the angle of rotation (α) on the basis of the determined angle of rotation value.

13. The regulating system (27) according to claim 12, wherein the regulating system (27) is embodied as a throttle sensor, an accelerator pedal value sensor, a body elasticity sensor or an angle sensor of a wiper.

14. A method for manufacturing a measuring device (1) according to one of the claims 1 to 11,

providing a first member (3);

connecting a magnet (7) to the first component (3) in a rotationally fixed manner;

providing a second member (5);

connecting a magnetically active element (9) to the second component (5) in a rotationally fixed manner;

rotatably mounting the first component (3) and the second component (5) about a common axis of rotation (11) in such a way that the first component (3) and the second component (5) can rotate relative to each other,

wherein the magnetically active element (9) is designed to determine a rotation angle value of the first component (3) with respect to the second component (5) as a function of a magnetic field (13) of the magnet (7), wherein the magnet is designed as a permanent magnet and the N and S poles of the magnet are in a horizontal direction, wherein the magnet (7) has a first section (80) along the axis of rotation (11) which has a first outer diameter (D1) in a plane transverse to the axis of rotation (11), wherein the magnet (7) has a second section (82) along the axis of rotation (11) which is connected to the first section (80) and which has a second outer diameter (D2) in a plane transverse to the axis of rotation (11), wherein the second section (82), viewed along the axis of rotation (11), is located between the first section (80) and the magnetically active element (9), and the magnetically active element (9) is opposite an end side of a second section (82), wherein the first outer diameter (D1) is larger than the second outer diameter (D2), the second outer diameter (D2) being between 30% and 70% of the first outer diameter (D1).