DE102013202891A1 - Position sensor, such as angle sensor or linear sensor for detecting position, has magnetic fields of coil unit and permanent magnet that are superimposed on another magnetic field to actuate actuating portion at actuation position - Google Patents

Abstract

The position sensor (1) has a magnetic unit (8), which comprises a coil unit and a permanent magnet, and which generates the magnetic force. The coil unit and the permanent magnet are arranged, so that the magnetic fields of the coil unit and the permanent magnet are superimposed on another magnetic field (B) to actuate an actuating portion (7) at an actuation position (P). The two electrodes (4,5) that are arranged on two support structures (2,3) form a potentiometer device that extends along a measurement path (M).

Description

The invention relates to a position sensor with a first carrier body, wherein on the first carrier body, a first electrode is arranged, with a second carrier body, wherein on the second carrier body, a second electrode is arranged, wherein the first and the second electrode form a potentiometer, the extends along a measuring path, with a magnetically actuable actuating portion which is arranged on the second carrier body and extending along the measuring section and with a magnetic device, wherein the magnetic device along the measuring path is slidably disposed and wherein the magnetic device is formed, the actuating portion on a selectable Actuation position to be actuated by a magnetic force, wherein the actuation of the actuating portion, the two electrodes arrive at the actuation position in an electrically conductive contact.

Sensor devices for determining a position are known in a large number of embodiments, for example as position encoders or angle encoders. A particular design relates to sensor devices which determine a position on the location of contact areas between flat electrodes, wherein the determination is made via a Potentiometerschaltung.

For example, the document discloses DE 10 2009 013 533 A1 , which is probably the closest prior art, a position sensor, which is a base support with a component of a position detection circuit and a flexible contact carrier, which is spaced from the component of the position detection circuit of the base support, wherein the flexible contact carrier locally locally elastically deformable by locally acting actuating forces in that it allows local electrical contacting of two components of the position sensing circuit. The actuating forces are generated, for example, by a permanent magnet or, alternatively, by an electromagnet which locally deforms the flexible contact carrier by magnetic force. By evaluating the position detection circuit, the absolute position or position of this electrical contact can be determined.

Field of the invention

The invention has for its object to provide a position sensor, which has an improved accuracy compared to the prior art.

These objects are achieved by position sensors having the features of claim 1, claim 4 and claim 7. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

It is a basic idea of the invention that the range of local deflection of the flexible contact carrier due to stray fields of the magnets, so either the permanent magnet or the electromagnet, is comparatively far, so that the linearity of the sensor device and thus the reproducibility of the position detection is deteriorated. A large contact area resulting from the wide deflection leads to a comparatively large hysteresis, which impairs the reliability and the accuracy of the sensor devices.

As a remedy, various alternatives are proposed according to the invention, which lead to a bundling, concentration and / or homogenization of the magnetic fields, whereby the region of the local deflection is kept narrow on the one hand and reproducible on the other hand, so that the aforementioned disadvantages are avoided or at least reduced ,

In the context of the invention, a position sensor is proposed which is suitable and / or designed for determining a position on the position sensor.

The position sensor comprises a first carrier body, wherein at least or exactly a first electrode is arranged on the first carrier body and a second carrier body, wherein on the second carrier body at least one or exactly one second electrode is arranged. The first and the second electrode together form a potentiometer device which extends along a measuring path. In particular, the first and the second electrode extend along the measuring path.

Furthermore, the position sensor comprises a magnetically actuatable actuating section, which is arranged on the second carrier body and likewise extends along the measuring path. In particular, the assembly comprising the second electrode and the magnetically actuatable actuating portion is flexible or bendable or deflectable.

The position sensor further comprises a magnetic device, which is arranged along the measuring path displaceable relative to the first and / or to the second carrier body. It is thus possible for the magnet device to be arranged so as to be stationary and the first and second carrier bodies to be movable are, or that the first and the second carrier body stationary and the magnetic device is designed to be movable. The magnet device generates a magnetic field or a magnetic force which locally actuates the magnetically actuatable actuating section at a selectable actuating position. Thus, the magnet means is shifted relative to the first and / or second carrier body to the selectable operating position and actuated at the selected operating position of the magnetically actuatable actuating portion by the magnetic force. By the actuation of the actuating portion, at least the second electrode is deflected in such a way that the first and the second electrode reach an electrically conductive contact at the actuating position. In particular, the deflection takes place perpendicular to the longitudinal extension of the measuring section and / or to the direction of displacement of the magnetic device.

To realize the potentiometer device, it is preferred that at least one of the electrodes is designed as a resistance path. The potentiometer device may be designed such that the resistance path and a collector path are arranged on a carrier body, wherein the two paths are conductively connected to one another by the electrode on the other carrier body. Alternatively, it is also possible that the one electrode forms the resistance path and the other electrode is designed as a collector path.

An evaluation device, which optionally forms part of the position sensor, can determine the selected actuation position on the basis of an electrical measurement variable, for example a resistance, based on the contact position of the electrodes. Preferably, the position sensor is designed as a film potentiometer.

The magnetically actuatable actuating section can be designed, for example, as a soft-magnetic or ferromagnetic actuating body or area which extends along the measuring section. Further possibilities for realizing the actuating section are, for example, ferromagnetic particles which are distributed on the second carrier body or in a position parallel to the second electrode along the measuring path. The actuating portion may also be formed of a plurality of layers, in particular ferromagnetic film layers.

In the invention, it is proposed in a first alternative that the magnetic device has at least or exactly one coil device and at least or exactly one permanent magnet, wherein the coil device and the permanent magnet are arranged such that overlap their magnetic fields to the actuating portion at the actuation position to operate together. In particular, the coil device and the permanent magnet are displaced together relative to the first and / or second carrier body. In particular, the magnetic fields are superimposed rectified, so that increases the magnetic field strength at the operating portion.

By means of the first alternative of the inventive concept, it is achieved that the local distribution of the overall resulting magnetic field in the region of the actuating section is more homogeneous. Thus, a superimposition of the magnetic field of the coil device, which is usually very easy to control, with the magnetic field of the permanent magnet, which usually also stray fields, resulting in a resulting common magnetic field, which can operate the operating section in more detail. In particular, the coil device achieves a local elevation of the common magnetic field, which actuates the actuation section in a defined manner. A further advantage of this first alternative is that the resulting magnetic field is at least co-generated by the permanent magnet, so that the demand for the current supply to the coil device is low.

Preferably, the at least one coil device is designed as a so-called air coil. In particular, in the region enclosed by the coil, a non-magnetic material, in particular air, is arranged as core material. For example, plastic can also be used as support material in the core material position in the air-core coil.

In a first possible embodiment, the coil device is arranged on a side facing away from the actuating portion of the first carrier body. In this embodiment, the magnetic device comprising the coil device and the permanent magnet can be arranged on one side of the first and / or second carrier body and be structurally simply displaced relative thereto.

In a modified embodiment of the invention, the at least one coil device is arranged on a side facing the actuating portion of the second carrier body. In this embodiment, it is preferred that the first and the second carrier body between the permanent magnet and the at least one coil means is arranged. In this embodiment, it is possible to bring the permanent magnet closer to the carrier body in order to obtain in this way a more homogeneous magnetic field in the region of the actuating portion.

In a further development of the invention or a second alternative according to the preamble of claim 1 of the invention, the magnetic device comprises two coil devices, as have been previously described, wherein the first and / or the second carrier body and / or the actuating portion disposed between the two coil means is. It is thus possible within the scope of a further development of the first alternative that the position sensor has the permanent magnet and at least two coil devices which are arranged in the manner of a clip around the first and / or second carrier body. Alternatively, it is possible that the position sensor has only the at least or exactly two coil devices and dispenses with the permanent magnet.

Due to the two coil devices, it is advantageously possible to generate a very homogeneous magnetic field in the region of the actuation section and thus to locally actuate and limit it. Preferably, the two coil means are arranged coaxially with each other. In advantageous developments of the invention, these also have the same diameter and the same number of turns. In particular, the two coil devices are arranged in a so-called Helmholtz arrangement, wherein the radius of the two coil devices is the same and at the same time corresponds to the distance of the two coil devices to one another. In this Helmholtz arrangement particularly homogeneous magnetic fields can be achieved, so that it is assumed that a constant and reproducible force on the operating section.

In a preferred development of the invention, the position sensor comprises a sensor device for measuring the magnetic field strength, which preferably forms part of the magnetic device or is at least carried along with it. Furthermore, the position sensor comprises a control device for controlling the flow of current through the at least one coil device. The control device is designed to control the flow of current as a function of the measured field strength, in particular to control or regulate. By means of such an active field control, the force effect on the actuating section is controlled according to the ambient conditions, in particular the temperature, of interference fields and of the movement speed of the magnetic device, etc. As a result, the range of the local deflection of the actuating portion and thus the performance, in particular the linearity and the reproducibility, of the position sensor can be improved. The sensor device is designed, for example, as a magnetic sensor, in particular as a Hall sensor or as an XMR sensor.

In a development of the invention or in a third alternative of the invention according to the preamble of claim 1, the magnetic device comprises one or the permanent magnet, which is designed to generate the magnetic force or a part of the magnetic force.

• • Fe 80 B 20
• • Fe 70 P 20 C 10
• • Co 58 Ni 10 Fe 5 (Si, B) 27
• • Fe 39 Ni 39 (Mo, Si, B) 22

It is proposed that a material section with a permeability greater than 30,000 be arranged on the permanent magnet in order to homogenize and / or to concentrate the orientation of the magnetic field of the permanent magnet in the direction of the actuating section. Thus, the material portion has a permeability which is 30000 greater than the permeability of air. Optionally, in addition, it is preferable for the material section to have a low coercive force H _{C of} less than 1000 A / m. The material section is preferably designed not to permanently magnetize. In particular, the material portion is formed as an amorphous metal alloy, as this example in the document DE 19681738 B4 is described and whose content is incorporated by referencing in the present application. In particular, soft magnetic materials which are formed as amorphous alloys can be used for the material section. Amorphous alloys consist of or include a transition metal such as Fe, Co, Ni, Cr, and M, as well as a metalloid (glass former) such as B, P, C, and Si. By way of example, the following alloys can be used:

• • Fe 80 B 20
• • Fe 70 P 20 C 10
• Co 58 Ni 10 Fe 5 (Si, B) 27
• • Fe 39 Ni 39 (Mo, Si, B) 22

It has been shown that the use of such a material section with the stated permeability can change the shape of the magnetic field, in particular the magnetic field can be parallelized or focused in certain areas. Particularly preferably, it is provided that the material portion with the high permeability is arranged on a pole of the permanent magnet on a side facing away from the actuating portion of the permanent magnet. In this arrangement, it has been experimentally shown that on the side facing the operating portion a very homogeneous and also concentrated magnetic field can be generated.

In a further development of the invention, provision is made for a pole piece to be placed on the side of the permanent magnet facing the actuating section, which leads to a further homogenization and / or bundling of the magnetic field.

In a structural embodiment of the invention can be provided that the position sensor is designed as a linear sensor or as an angle sensor. In the training as a linear sensor, it is preferred that the measuring section is linear or rectilinear, in the form of an angle sensor, this can for example take a circular shape. Also intermediate forms between a linear and a circular measuring section, such as an oval etc. measuring section are conceivable within the scope of the invention.

Further features, advantages and effects of the invention will become apparent from the following description of preferred embodiments of the invention. Showing:

1 a schematic representation of a position sensor as an embodiment of the invention;

2 a first embodiment of the detail A of the position sensor in the 1 ;

3 a second embodiment of the detail A in the 1 ;

4 a third embodiment of the detail A in the 1 ;

5 a fourth embodiment of the detail A in the 1 ;

6 a fifth embodiment of the detail A in the 1 ,

The 1 shows a schematic representation of a position sensor 1 as an embodiment of the invention.

The position sensor 1 comprises a first carrier body 2 and a second carrier body 3 , which are formed for example as films. On the first or second carrier body 2 . 3 is a first electrode 4 or a second electrode 5 arranged. The electrodes 4 . 5 extend along a measuring section M. The electrodes 4 . 5 are spaced apart, in particular by a gap 6 separated from each other. On the back of the second carrier body 3 , So on the first carrier body 2 opposite side, is an operating section 7 arranged, which also extends along the measuring path M. At least the operating section 7 and the second electrode 5 are flexible, in particular bendable formed, optional complementary is also the second carrier body 3 designed to be flexible, in particular bendable.

The position sensor 1 includes a magnetic device 8th which in the 1 indicated only schematically and along the measuring section M relative to the carrier bodies 2 . 3 slidably arranged. Thus, with the magnetic device 8th an arbitrary actuating position P along the measuring section M are selected. The magnetic device 8th is designed to generate a magnetic field B, which on the operating portion 7 locally at the operating position P, the operating portion 7 attracts due to a magnetic force. The attraction becomes the operation section 7 locally in the region of the actuation position P together with the second electrode 5 in the direction of the first carrier body 1 deflected or bent so that the second electrode 5 in electrical contact with the first electrode 4 occurs.

The electrodes 4 . 5 are formed together as potentiometer means, wherein at least one of the electrodes 4 . 5 is designed as a resistance path, so that the position of the actuation position P along the measurement path M can be determined metrologically by tapping the resistance path.

In order to achieve the most accurate determination of the actuation position P, it is advantageous that the actuation of the actuation section 7 reproducible and with a small extension along the measuring section M takes place. In order to achieve this, various alternatives of an advantageous and exemplary embodiment of the magnetic device will be described below with reference to the exemplary embodiments 8th shown:
That's how it shows 2 the detail A in the 1 as a first embodiment of the invention. The carrier bodies are again highly schematic 2 . 3 with the electrodes 4 . 5 and the operation section 7 shown. The magnetic device 8th in this embodiment comprises a permanent magnet 9 and a coil device 10a , where permanent magnet 9 and coil means 10a on the same side with respect to the carrier body 2 . 3 are located. The permanent magnet 9 and the coil means 10a are arranged so that their magnetic fields overlap to form a common magnetic field B. Here is the permanent magnet 9 arranged so that its magnetic field MP rectified and at least in the center parallel and coaxial with the magnetic field MS of the coil means 10a is directed. Due to the superimposition of the magnetic fields MP and MS, a homogeneous field line distribution is achieved in the center of the common magnetic field B, which produces a reproducible actuation of the actuation section 7 allows. Particularly preferred is the coil device 10a designed as a so-called air coil, which optionally has air or a magnetically non-active material in the interior.

Furthermore, the magnetic device comprises 8th a sensor device 11 , which is designed to measure the magnetic field B. The sensor device 11 can be realized for example as a Hall sensor. The sensor device 11 is with a control device 12 connected, which on the basis of the measurement signals of the sensor device 11 the current of the coil device 10a controlled, in particular controls or regulates. This supplementary measure ensures that the position sensor 1 can be operated reproducibly and very accurately even if, for example, interference fields or different temperatures occur in the operating environment.

The 3 shows a modification of the magnetic device 8th in the 2 in the same representation as the 2 , In contrast to the embodiment in the 2 is a coil device 10b on one of the permanent magnets 9 opposite side of the carrier body 2 . 3 arranged. While the embodiment in the 2 has the advantage that the permanent magnet 9 and the coil means 10a on a common side of the carrier body 2 . 3 relative to the carrier bodies 2 . 3 It can be moved, it is an advantage of the embodiment in the 3 that the permanent magnet 9 closer to the carrier bodies 2 . 3 can be arranged. The displacement of the magnetic device 8th For example, by a forked or U-shaped receptacle for the permanent magnet 9 and the coil means 10b respectively.

The 4 shows a third embodiment of the magnetic device 8th In this embodiment, both the coil means 10a as well as the coil device 10b are present, wherein between the coil means 10a , b the carrier body 2 . 3 are arranged. In the in the 4 shown embodiment was also on the permanent magnet 9 waived.

By the illustrated arrangement, wherein the coil means 10a , B are arranged coaxially to each other and each having the same number of windings and the same diameter, a particularly homogeneous, common magnetic field B in the region of the actuating portion 7 be generated. For example, it is possible to use the coil devices 10a to position b in a so-called Helmholtz arrangement, wherein the radius of the coil means 10a , b the distance of the coil means 10a , b corresponds to each other.

In the 5 is the magnetic device 8th of the 4 together with the permanent magnet 9 shown in addition to the coil devices 10a , b can be used.

In the 6 is another embodiment of the magnetic device 8th shown, these being the permanent magnet 9 includes. On the carrier bodies 2 . 3 opposite sides of the permanent magnet 9 is a layer of material 13 applied, which has a permeability greater than 30,000. Through the layer with the very high permeability, the magnetic field MP of the permanent magnet 9 and thus the magnetic field B is distorted such that in the region of the actuating portion 7 the field lines of the magnetic field B are bundled and also arranged parallel to each other. This embodiment thus provides a passive possibility for improving the magnetic field B in the region of the actuating portion 7 represents.

To further optimize the magnetic field B is on the support bodies 2 . 3 facing side of the permanent magnet 9 also a pole piece 14 placed. The Indian 6 illustrated permanent magnet 9 with the material layer 13 and optionally in addition to the pole piece 14 can also in the embodiments in the 2 . 3 and 5 be used.

LIST OF REFERENCE NUMBERS

1

 position sensor

2

 first carrier body

3

 second carrier body

4

 first electrode

5

 second electrode

6

 gap

7

 actuating section

8th

 magnetic device

9

 permanent magnet

10a, b

 coil means

11

 sensor device

12

 control device

13

 material layer

14

 pole

P

 operating position

B

 magnetic field

M

 measuring distance

MP

Magnetic field of the permanent magnet 9

MS

Magnetic field of the coil device 10a respectively. 10b

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009013533 A1 [0003]
• DE 19681738 B4 [0024]

Claims (10)

Position sensor ( 1 ) with a first carrier body ( 2 ), wherein on the first carrier body ( 2 ) a first electrode ( 4 ) is arranged, with a second carrier body ( 3 ), wherein on the second carrier body ( 3 ) a second electrode ( 5 ), wherein the first and second electrodes ( 4 , 5) form a potentiometer device which extends along a measuring path (M), with a magnetically actuatable actuating portion ( 7 ), which on the second carrier body ( 3 ) is arranged and extends along the measuring section (M), with a magnetic device ( 8th ), wherein the magnetic device ( 8th ) is slidably disposed along the measuring section (M) and wherein the magnetic device ( 8th ) is formed, the actuating portion ( 7 ) at a selectable operating position (P) by a magnetic force, wherein by the actuation of the actuating portion ( 7 ) the two electrodes ( 4 . 5 ) arrive at the actuation position (P) in an electrically conductive contact, characterized in that the magnetic device ( 8th ) for generating the magnetic force at least one coil device ( 10a , b) and a permanent magnet ( 9 ), which are arranged so that the magnetic fields (MS, MP) of the at least one coil device ( 10a , b) and the permanent magnet ( 9 ) to a magnetic field (B) overlay the operating section ( 7 ) at the operating position (P). Position sensor ( 1 ) according to claim 1, characterized in that the at least one coil device ( 10a , b) on an operating section ( 7 ) facing away from the first carrier body ( 2 ) is arranged. Position sensor ( 1 ) according to claim 1, characterized in that the at least one coil device ( 10b ) on an operating section ( 7 ) facing side of the second carrier body ( 3 ) is arranged. Position sensor ( 1 ) according to one of the preceding claims or according to the preamble of claim 1, characterized in that the magnetic device ( 8th ) two coil devices ( 10a , b), wherein the first and / or the second carrier body ( 2 . 3 ) and / or the operating section ( 7 ) between the two coil devices ( 10a , b) is arranged. Position sensor ( 1 ) according to claim 4, characterized in that the two coil devices ( 10a , b) are arranged in a Helmholtz arrangement. Position sensor ( 1 ) according to one of the preceding claims, characterized in that the position sensor ( 1 ) a sensor device ( 11 ) for measuring the magnetic field strength and a control device ( 12 ) for controlling the flow of current through the at least one coil device ( 10a , b), wherein the control device ( 12 ) is designed to control the current flow in dependence on the measured magnetic field strength. Position sensor ( 1 ) according to the preamble of claim 1 or any one of the preceding claims, wherein the magnetic device ( 8th ) one or more permanent magnets ( 8th ) for generating the magnetic force or a part of the magnetic force, characterized in that on the permanent magnet ( 8th ) a material section ( 13 ) having a permeability greater than 30,000 is arranged to shape the orientation of the magnetic field (MP, B) toward the actuating portion. Position sensor ( 1 ) according to claim 7, characterized in that the material section ( 13 ) on an operating section ( 7 ) facing away from the permanent magnet ( 9 ) is arranged. Position sensor ( 1 ) according to one of claims 7 or 8, characterized in that on the permanent magnet ( 8th ) a pole piece ( 14 ) is attached. Position sensor ( 1 ) according to one of the preceding claims, characterized in that the position sensor ( 1 ) is formed as a linear sensor or as an angle sensor.

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