EP1133676A1

EP1133676A1 - Measuring device for the contactless measurement of an angle of rotation

Info

Publication number: EP1133676A1
Application number: EP99955755A
Authority: EP
Inventors: Asta Reichl; Thomas Klotzbuecher
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1998-11-17
Filing date: 1999-09-22
Publication date: 2001-09-19
Also published as: DE19852915A1; US6611790B1; WO2000029813A1; AU756850B2; JP2002530636A; AU1261100A

Abstract

The inventive measuring device for the contactless measurement of an angle of rotation gamma consists of a soft-magnetic base plate (14) which serves as a rotor. Two segments (16, 17) are arranged in one plane with the base plate (14) and are separated by a slot (21) and a spacer gap (22). The base plate (14) is mounted on the pin (11). The extension (12) of said pin or the pin (11) itself consists of magnetically conductive material. A magnet (15) is arranged on the base plate (14). Said magnet (15) is smaller than the angle of rotation gamma and can be a single-block magnet or a magnet consisting of several members. The arrangement of the magnet (15) facilitates reproduction of various sections, for example, plateaus or sections deviating from the linear measuring line, within the measuring curve detected by the measuring device.

Description

Measuring device for contactless detection of an angle of rotation

State of the art

The invention relates to a measuring device for contactless detection of an angle of rotation according to the preamble of claim 1. From DE-OS 196 34 381.3 a sensor is known which is arranged in three planes one above the other. The rotor forms the middle level, whereby it consists of the carrier plate for a permanent magnet. The carrier plate itself consists of magnetically non-conductive material, so that the magnetic flux over the other two levels, i.e. the stator, and is scattered with the help of two spacers, which are arranged between the two levels of the stator. The shaft or the extension of a shaft that is attached to the rotor has no influence on the magnetic flux. With this sensor, a relatively large angular range can be measured without changing the sign, but it is relatively large in the axial direction due to the construction in three parallel planes.

Furthermore, it is known in the case of potentiometers to achieve a kinking measuring line by undersilving the contact tracks in the area of the flattening. Advantages of the invention

The measuring device according to the invention for contactless detection of an angle of rotation with the characteristic

Features of claim 1 has the advantage that the sensor has a relatively small size in the axial direction. It only builds on two levels. The carrier plate of the permanent magnet, which represents the rotor, also serves to guide the magnetic flux. Furthermore, the shaft or axis on which the rotor is seated is included in the guidance of the magnetic flux, as a result of which there is no need for additional magnetic flux guide pieces. Furthermore, the number of parts and the associated assembly effort are reduced by this construction.

By varying the length of the magnet or dividing it into individual sections, a measurement curve with one or more flattened portions can be generated in a simple manner.

The sensor can be integrated in various systems, such as a throttle measuring device, a pedal module for an accelerator pedal value sensor, or as an independent sensor in throttle valve sensors or one due to its simple construction with relatively little installation effort

Body suspension device usable.

The measures listed in the subclaims allow advantageous developments and improvements of the measuring device specified in claim 1.

drawing

Embodiments of the invention are shown in the drawing and explained in more detail in the following description. Figures 1 to 4 show different views or sections through a first embodiment1. 1 shows a longitudinal section in viewing direction X according to FIG. 3, FIG. 2 shows a section BB according to FIG. 4, FIG. 3 shows a plan view in viewing direction Y according to FIG. 1, and FIG. 4 shows a longitudinal section in direction AA according to FIG. 3. FIGS. 5 and 6 show the magnetic flux at an angular rotation of zero degrees or an induction B = zero, Figures 7 and 8 show the corresponding magnetic flux at an angular rotation α or with an induction B = Max, Figures 9 and 10 show the magnetic flux in the angular range ß and . in the

Plateau range with an induction B = Max, FIG. 11 shows the corresponding course of the induction B over the entire angle of rotation γ (γ = α + ß). Further exemplary embodiments are shown in FIGS. 12 to 23, wherein FIGS. 12 to 15 represent an embodiment with a two-part magnet, FIGS. 16 to 19 show a magnet with a first slot shape and FIGS. 20 to 23 show a two-part magnet with a slot in the carrier FIGS. 24 to 30 show the magnetic flux profile over the angle of rotation and FIGS. 31 and 32 are designed with radially magnetized magnets.

Description of the embodiments

In FIGS. 1 to 4, 10 denotes a sensor which is connected with the aid of an axis 11 to a component, not shown, whose rotational movement is to be determined. On the end face of the axis 11, an extension 12 is attached, so that a shoulder 13 is formed, on which a support plate 14 is placed in the center, which also serves as a rotor. The axis 11, the extension 12 and the carrier plate 14 can be produced both as individual components and as a single component. An annular permanent magnet 15 is arranged on the carrier plate 14 as far as possible with a large radial distance from the center point, ie from the starting point of the axis 11. The bigger here the distance is, the better the resolution of the measurement signal. The permanent magnet 15 can be designed as a circular segment (circle segment) or part of a circular ring. However, its angular range α is smaller than the maximum rotation angle γ to be determined of the component to be monitored or measured. As can be seen from the illustrations in FIGS. 2 and 3, the angular range α of the permanent magnet 15 in this exemplary embodiment is approximately 100 degrees, but the total working measuring range is γ = 180 degrees. The difference angle β would cause the plateau P shown in FIG. 11. The permanent magnet 15 is also polarized in the axial direction, ie perpendicular to the carrier plate 12. The carrier plate 14 consists of magnetically conductive, in particular soft magnetic material. According to the invention, the axis 11 and the extension 12 or at least the extension 12 also consist of magnetically conductive, in particular soft magnetic material.

In a second plane above the permanent magnet 15, a stator is arranged parallel to the carrier plate 14 at a short distance, which stator consists of two segments 16, 17. The segment 16 encloses the extension 12 with an arc 19. In this exemplary embodiment, the arc 19 is designed as a circular arc. However, a different contour is also conceivable. It is essential, however, that a magnetically conductive connection between the extension 12 and the segment 16 is possible. The gap 20 between the axis 11 and the arc 19 is therefore to be made as small as possible. A continuous gap is formed between the two segments 16, 17, which in the exemplary embodiment according to FIGS. 1 to 4 has two identical outer sections 21 and a central spacing gap 22 located in the region of the arc 19. With the spacing gap 22 it is important that between the

Segments 16 and 17, ie in this embodiment in In the region of the arc 19, as far as possible, no magnetic flux, which is generated by the permanent magnet 15, is possible. The spacing gap 22 can therefore be filled with air or another magnetically non-conductive material. If the spacing gap 22 is filled with air, for example, it must be in the

Relationship to the gap 21 may be made larger in order to achieve this effect mentioned above. Instead of air, another, magnetically non-conductive material can also be selected. The column 21 and the distance gap can also be filled with different materials. At least in one of the columns 21, a magnetic field sensitive element 25, such as a field plate, magnetic transistor, coils, magnetoresistive element or a Hall element, is arranged approximately in the center. It is important here that the magnetic field-sensitive component has a linear dependence of its output signal on the magnetic induction B. FIGS. 1 to 4 each show a measurement using a single magnetic field-sensitive element 25, in this case a Hall element. In this case, the element 25 must be arranged as centrally as possible in the gap 21. On the other hand, it would also be possible, for example, to arrange one element 25 in each of the two columns 21, for example in order to be able to carry out a so-called redundant measurement (safety measurement). It would also be conceivable to arrange two elements in a gap. If, as can be seen in FIG. 3, a magnetic field-sensitive element 25 is arranged only in one gap 21, the opposite gap 21 can also have the size of the distance gap 22 and thus have the magnetically non-conductive function which is in the distance gap 22.

FIG. 11 shows the course of the characteristic curve of the magnetic induction B in the element 25, e.g. B. a Hall element over the angle of rotation γ of the axis 11 is shown. It can be seen that at a rotation angle γ of 0 ° Induction B is also 0, while at the maximum angle of rotation γ = max it also reaches the maximum induction value. In this embodiment, the maximum angle of rotation γ is reached at 180 °. The position of the sensor 10 at an angle of rotation of 0 ° is shown in FIGS. 5 and 6. It can be seen that the magnetic flux from the permanent magnet 15 via the air gap 100 to the segment 17, from there via the small gap 20, which serves to move the rotor relative to the stator, to the extension 12 and from there via the carrier plate 14 back to

Permanent magnets 15 lead. As can be seen in particular from FIG. 6, the magnetic flux is controlled so that it does not run through the element 25 at an angle of rotation of 0 °, so that no magnetic induction B can take place in the element 25. If the axis 11 and thus the carrier plate 14 with the permanent magnet 15 are now rotated, the magnetic flux passing through the element 25 is increased, and the linear measurement line H shown in FIG. 11 is obtained note that the rotor moves counterclockwise. At the end of measuring line H, i.e. at point B the permanent magnet 15 has just completely passed the gap 21. It also means that the permanent magnet 15 is now completely under the segment 16. This position B after the angle of rotation α also represents the position of the maximum

Magnetic flux of the permanent magnet 15 over the gap 21. When further rotation around the angular range β to achieve the total rotation range γ, there is no change in the induction B in the measuring gap 21 and thus in the measuring element 25. This results in a plateau region P in the diagram according to the figure 11. The end position in point C, after turning through the angle ß, ie after this

Total rotation range γ is shown in FIGS. 9 and 10. It can be seen in particular from FIGS. 8 and 10 that when the gap 21 is passed, almost the entire magnetic flux is guided through the element 25 and thereby in the element 25 a maximum possible magnetic induction B is effected. Furthermore, it can be seen from these two FIGS. 8 and 10 that the spacing gap 22 causes the magnetic lines to run almost completely over the gap 21 and thus through the element 25. There should be no magnetic flux through the spacing gap 22 if possible.

It is essential to the invention that the permanent magnet 15 is smaller than the entire measuring range γ or smaller than the segment 17 serving as a flux guide. In the previous embodiments, the permanent magnet 15 was formed in one piece and arranged on the carrier 14 so that the beginning of the permanent magnet was also at the beginning of the rotation range. In the exemplary embodiment according to FIGS. 12 to 15, the permanent magnet is now constructed in two parts. Due to this two-part construction, the plateau region P, which corresponds to the rotation region β of the sensor 10, is shifted between two linear curve sections (FIG. 30). The size of the two ring-shaped or segment-shaped permanent magnet parts 15a and 15b can be of different sizes or the same size. The two parts are magnetized in the same direction. Because the measuring range β now lies between the two permanent magnet parts 15a and 15b, the plateau region P is shifted into the course of the measuring line A, so that a characteristic curve similar to that shown in FIG. 30 is obtained. FIG. 30 shows a characteristic curve in which the two permanent magnet parts 15a and 15b would be the same size. Furthermore, it would also be possible to arrange more than two permanent magnet parts, ie three, four etc. This would make it possible to generate a correspondingly desired number of plateaus in the measuring line. Instead of a permanent magnet, it would also be possible to generate magnetized areas on the carrier plate. This embodiment would be applicable to all of the exemplary embodiments mentioned here. With the help of the plateau or plateaus or from the actual measurement curve different sections, controls can be carried out.

While there is a separation of the two permanent magnet parts 15a and 15b in the previous exemplary embodiments, the parts can also be connected to one another with a small web. A corresponding embodiment is shown in Figures 16-19. The web 50 is located on the inside in FIG. it connects the inner radius of the two

Permanent magnet pieces 51a and 51b with each other. Of course, it would also be possible to arrange the connecting web 50 on the outer edge or in the middle. Because of this connecting web 50, the measurement curve in the area of the rotation angle β no longer runs flat as a plateau, as in the previous exemplary embodiments and shown in FIG. 11, but depending on the width of the connecting web 50, this area of the diagram has an incline in the rotating area β . The slope can be influenced via the size, in particular the radial width. This means that a wider web than the permanent magnet parts is possible and thus a steeper curve shape can be achieved in this area than in the area of the permanent magnet parts.

The exemplary embodiment in FIGS. 20-23 likewise shows a two-part permanent magnet as is shown in a similar manner in FIGS. 12-15. The two permanent magnet parts 61a and 61b have the same size, ie the same angular range. This means that the angular range is α1 = α2. The two permanent magnet parts 61a and 61b are arranged so that the angular range β is between the two parts. In addition, a slot is also formed in the support 14 in the region β. This slot 62 serves to make a relatively sharp transition between the linear ones Characteristic and to reach the plateau area P in the measuring range ß. It can also be seen from FIGS. 21 and 20 that the carrier plate 14a does not have to be an entire disk, but rather only serves as a support surface for the permanent magnet parts 61a and 61b and for attachment as a rotor to the axis 11 or its extension 12.

Whereas in the previous exemplary embodiments a magnetic flux was controlled via the magnetically conductive extension 12 of the axis 11, FIGS. 24 to 29 and the associated diagram in FIG. 30 show a design of a sensor 70 in which the magnetic flux does not pass over the axis and / or an extension of the axis, but is controlled via a reflux part 72 attached to a segment 17a of the stator serving as a flux guide part. In FIG. 24 it can be seen that there is a carrier 14b on the axis 11a, which has the same properties as the carrier 14 or 14a in the previous exemplary embodiments. A stator, which consists of two segments 16a and 17a, is arranged in a second plane above the carrier plate 14b, which serves as a rotor. A magnetic field sensitive element 25a is arranged in the slot 21a between the two segments 16a and 17a. An element as described in the other exemplary embodiments can be used as the magnetic field-sensitive element 25a. A reflux part 72 is arranged on the segment 17a and encompasses the entire circular lateral surface of the segment 17a. It has a length that it projects beyond the carrier plate 14b. Like the two segments 16a and 17a, it is made of magnetically conductive material. It can also be seen from FIG. 25 that the permanent magnet located on the carrier plate 14b consists of two parts 71a and 71b. Both parts 71a and 71b are the same size, which means that the angular range αl = α2. The measuring range β is again between the two permanent magnet parts 71a and 71b. In the figures 24 and 25, the position at an angle of rotation γ = 0 ° and an induction B = 0 is shown. When the axis 11a and thus the carrier plate 14b rotate counterclockwise, the first magnetic part 71a is moved over the gap 21a and is located in the region of the segment 16a to an ever increasing extent. The position is now shown in FIGS. 26 and 27 when the measuring range β is above the gap 21a. As long as the magnetic part 71a moves under the segment 16a, the characteristic curve, as shown in FIG. 30, increases linearly. Once the whole

Permanent magnet part 71a has exceeded the gap 21a, the plateau P begins which corresponds to the measuring range β. As soon as the magnetic part 71b then moves under the segment 16a, the measuring line rises again linearly and it reaches as soon as the permanent magnet part 71b completely, i.e. So both permanent magnet parts 71a and 71b are located under the segment 16a, the maximum induction B = max. In FIGS. 28 and 29, the position of the sensor 70 with the maximum angle of rotation position γ = max and maximum induction B = max. shown.

The sensors described in the exemplary embodiments are suitable, for example, for installation in a throttle valve actuator unit. With the help of this unit, the angle of rotation of a throttle valve for an engine control is detected. The segments 16, 17 of the stator can then be attached directly in the cover of the throttle valve actuating unit. Since the cover is made of plastic, the segments 16, 17 can also be injected into the cover. The two segments 16, 17 of the stator could possibly also be clipped into the cover.

FIGS. 31 and 32 now show an embodiment of an angle sensor 80 in which the permanent magnet or the permanent magnet parts are magnetized in the radial direction. In the angle sensor 80, one of the Segments 95 are connected with the aid of a bridge 96 to an outer, annular housing part 93. The second segment element 97 has no connection to the housing part 93, ie there is no magnetically conductive connection between the segment 97 and the housing part 93. Because of the bridge 96, the angular range to be determined is therefore limited, ie no measurements over an angle of approximately 200 ° are possible. In this embodiment, the segment 95, the bridge 96 and the housing part 93 can advantageously be produced as a one-piece component made of soft magnetic material, for example stacked transformer sheets or sintered material. Of course, it is also possible to design the segments 95, 97 not asymmetrically but also asymmetrically. In the slot 98 between the two segments 95 and 97, the magnetic field-sensitive element 99 is arranged, which can be configured as in the exemplary embodiments described above. In the illustration according to FIG. 31, the permanent magnet 91a, 91b arranged in the slot 100 comprises the segment 97. This means that the permanent magnet again consists of at least two permanent magnet parts 91a and 91b or of a single permanent magnet which has an angular range smaller than the segment 97 includes. The direction of polarization of the permanent magnet or of the two permanent magnet parts is fixed in a radial orientation. This means that the direction of magnetization is directed from the segment 97 to the housing part 93 or in the opposite direction. It cannot be seen from the illustration in FIGS. 31 and 32 that the permanent magnet or the two permanent magnet parts 91a and 91b are in turn on one

Carrier plate are located, which is connected to the rotating axis. FIG. 31 shows the position of the permanent magnet at an angle of rotation γ = 0 and FIG. 32 shows the position at a maximum angle of rotation γ = max. The resulting one during the rotation Measuring line corresponds in an analogous manner to the characteristic curve shown in FIG. 30.

Claims

Expectations

1.Measuring device for non-contact detection of an angle of rotation γ between a stator (16, 17) and a rotor (14), a magnet (15) being arranged on the rotor (14), with a stator (16, 17) and rotor (14) there is an air gap and the stator (16, 17) consists of at least two segments (16, 17) which are separated by a magnetically non-conductive gap (21, 22), with at least one gap (21) there is a magnetic field sensitive element (25), at least a part (17) of the stator having no magnetically conductive connection to the rotor (14), characterized in that the magnet (15) is made smaller than the angle of rotation γ to be measured.

2.Measuring device for non-contact detection of an angle of rotation γ between a stator (93, 95, 96, 97) made of magnetically conductive material and a rotor (91a, 91b), the stator (93, 95, 96, 97) and rotor ( 91a, 91b) there is an air gap (100) and at least one air gap (98) is formed in the stator (93, 95, 96, 97), there being at least one magnetic field-sensitive element (99) in the at least one air gap (99) and wherein at least one segment of at least one magnet is arranged in the rotor (91a, 91b), the stator (93, 95, 96) being constructed from a plurality of parts (93, 95, 96, 97), at least one part (97) being non-magnetic Has a conductive connection to the other parts (93, 95, 96) so that the magnetic flux of the magnet (91a, 91b) is split, at least a first part of the magnetic flux flowing through the magnetic field-sensitive element (99), characterized in that the Magnet (91a, 91b) smaller than that Angle of rotation γ to be measured is formed.

3.Measuring device according to claim 1 or 2, characterized in that the magnet (15, 91a, 91b) consists of several parts which are separated by a section of non-magnetic material.

4.Measuring device according to claim 3, characterized in that at least two parts of the magnet (51a, 51b) are connected to one another by means of a web (50).

5.Measuring device according to one of claims 1, 3 or 4, characterized in that the rotor consists of magnetically conductive material.

6.Measuring device according to claim 1 or one of claims 3-5, characterized in that at least one reflux piece (72) is arranged on one of the segments (16), which protrudes beyond the rotor (14).

7.Measuring device according to claim 1 or one of claims 3-5, characterized in that at least one reflux piece (72) is arranged on one of the segments (16), and that the rotor (14) projects beyond the reflux piece (72).

8.Measuring device according to claim 1 or one of claims 1- 5, characterized in that the axis (11) of the rotor

(14) has at least one area (12) made of magnetically conductive material which extends at least from the rotor (14) to the part (16) of the stator which has a magnetically conductive connection to the rotor (14) and that at least a first gap ( 22) is present between the two parts (16, 17) of the stator, which impedes the magnetic flux of the magnet (15) and controls it so that it runs over at least one of the other gaps (21), and that the first gap (22) is larger than the other gap (21).

9.Measuring device according to claim 8, characterized in that the shaft (11), in particular the extension (12), and the rotor (14) consist of soft magnetic material.

10.Measuring device according to claim 1 or 8 or 9, characterized in that a part (16) of the stator has an extension (19) into which the axis (11), in particular its extension (12) protrudes.