ELECTRONIC ANGLE SENSOR FOR INDICATOR INSTRUMENTS

Abstract

Indicator instruments (1) have a good readability of a measured value, so that a simple visual checking of the measured value by the user is possible. An electronic angle sensor (17), is integrated into an exiting indicator instruments (1) with a front side (2) viewed indicator (7). The electronic angle sensor (17) includes a sensor unit (39) for the contactless detection of an angular position of the indicator (7). This allows an integration of an existing indicator instrument (1) into a control or regulation circuit for reference to the measured variable and/or the reaching of a preset switching point (30) in the form of a data signal. Good readability of the indicator instrument (1) is not lost and the measuring system is not modified. The angle sensor (17) is mountable on the front side (2) and the sensor unit (39) uses the indicator (7) as a transducer (8).

Claims

1. An electronic angle sensor for indicator instruments provided with an indicator, to be viewed from a front side of the indicator instrument, the electronic angle sensor comprising: a sensor unit for a contactless detection of an angular position of the indicator, wherein the angle sensor is configured as mountable at the front side of the indicator instrument and the sensor unit is configured to use the indicator as a transducer of the sensor unit.

2. An electronic angle sensor in accordance with claim 1, wherein the sensor unit comprises measuring sectors, which are configured to measure an electrical and/or magnetic image of the indicator.

3. An electronic angle sensor in accordance with claim 2, wherein the measuring sectors are capacitive measuring sectors and the measurement, by the capacitive measuring sectors, is carried out capacitively.

4. An electronic angle sensor in accordance with claim 3, wherein the capacitive measuring sectors are aligned radially to a mounting axis of the indicator.

5. An electronic angle sensor in accordance with claim 2, wherein the measuring sectors are inductive measuring sectors and the measurement, by the inductive measuring sectors is carried out inductively.

6. An electronic angle sensor in accordance with claim 5, wherein directly adjacent measuring sectors are arranged radially offset to one another and/or overlapping in a circumferential direction.

7. An electronic angle sensor in accordance with claim 2, wherein the indicator at least partially covers at least two measuring sectors in each angular position.

8. An electronic angle sensor in accordance with claim 1, further comprising an output interface and a switching point, the reaching of which by the indicator triggers the output of a switching point signal via the output interface, wherein a position of the switching point is settable within a predetermined range at a desired angular position of the indicator.

9. An electronic angle sensor in accordance with claim 8, further comprising at least one display element displaying and/or setting the switching point, wherein the at least one display element is configured as rotatable.

10. An electronic angle sensor in accordance with claim 9, wherein the sensor unit is nonrotatably connected to the at least one display element.

11. An electronic angle sensor in accordance with claim 9, further comprising an analysis unit, an actuating element configured as manually actuatable, and a memory, wherein the electrical and/or magnetic image of the indicator, measured at the time of the actuation, is stored in the analysis unit upon actuation of the actuating element.

12. An electronic angle sensor in accordance with claim 11, wherein the analysis unit is configured to compare the stored electrical and/or magnetic image of the indicator with a currently measured electrical and/or magnetic image of the indicator and to signal a reaching of the at least one stored switching point in the case of agreement of a stored image with the current electrical and/or magnetic image of the indicator.

13. An electronic angle sensor in accordance with claim 1, wherein a cover glass is provided for the indicator instrument, on which the electronic angle sensor is mounted.

14. A process for the contactless detection of an angular position of the indicator of an indicator instrument, the process comprising the steps of: providing an electronic angle sensor comprising a sensor unit for a contactless detection of an angular position of the indicator, wherein the angle sensor is configured as mountable at the front side of the indicator instrument and the sensor unit is configured to use the indicator as a transducer of the sensor unit; mounting the electronic angle sensor on or adjacent to the front side of the indicator instrument; and detecting the angular position of the indicator from the front side of the indicator instrument and the indicator itself is used as the transducer.

15. A process in accordance with claim 14, wherein: the sensor unit comprises measuring sectors configured to measure an electrical and/or magnetic image of the indicator; and the indicator at least partially covers at least two measuring sectors in each angular position of the indicator.

16. A process in accordance with claim 15, wherein: the measuring sectors are capacitive measuring sectors and the measurement, by the capacitive measuring sectors, is carried out capacitively; and the capacitive measuring sectors are aligned radially to a mounting axis of the indicator.

17. A process in accordance with claim 14, wherein: the measuring sectors are inductive measuring sectors and the measurement, by the inductive measuring sectors is carried out inductively; and directly adjacent measuring sectors are arranged radially offset to one another and/or overlapping in a circumferential direction.

18. A process in accordance with claim 14, wherein: the electronic angle sensor further comprises an output interface and a switching point, the reaching of which by the indicator triggers the output of a switching point signal via the output interface, wherein a position of the switching point is set within a predetermined range at a desired angular position of the indicator; the electronic angle sensor further comprises at least one display element displaying and/or setting the switching point; the at least one display element is configured to be rotatable; the sensor unit is nonrotatably connected to the at least one display element.

19. A process in accordance with claim 14, wherein: the electronic angle sensor further comprises an analysis unit, an actuating element configured as manually actuatable, and a memory; the electrical and/or magnetic image of the indicator, measured at the time of the actuation, is stored in the analysis unit upon actuation of the actuating element; the analysis unit is configured to compare the stored electrical and/or magnetic image of the indicator with a currently measured electrical and/or magnetic image of the indicator and to signal a reaching of the at least one stored switching point in the case of agreement of a stored image with the current electrical and/or magnetic image of the indicator.

20. A process in accordance with claim 14, wherein: a cover glass is provided for the indicator instrument; and the electronic angle sensor is mounted on the cover glass.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0106] In the drawings:

[0107] FIG. 1 is a perspective view of a mechanical indicator instrument of the state of the art;

[0108] FIG. 2 is a perspective view of an indicator instrument with an electronic angle sensor;

[0109] FIG. 3 is a section of the perspective view of an indicator instrument with electronic angle sensor;

[0110] FIG. 4 is a perspective view of a capacitive electronic angle sensor;

[0111] FIG. 5 is a perspective view of an inductive electronic angle sensor;

[0112] FIG. 6 is the design of an indicator image and the setting of a switching point;

[0113] FIG. 6a is a first indicator image; and

[0114] FIG. 6b is a second indicator image.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0115] Referring to the drawings, an indicator instrument 1 of the state of the art is shown in FIG. 1. Such an indicator instrument 1 comprises a measuring unit 3 and a display unit 5, which in turn comprises an indicator 7, an instrument dial 9, a display housing 11 as well as a cover glass 13.

[0116] The measuring unit converts a measured variable into a proportional angle of rotation of the indicator axis 15, said angle of rotation being proportional to the measured variable.

[0117] The indicator 7 is connected nonrotatably to an indicator axis 15.

[0118] FIG. 2 shows an indicator instrument with an electronic angle sensor 17.

[0119] In addition to the technical features shown in FIG. 1, the embodiment of the indicator instrument shown in FIG. 2 additionally comprises a black print 19, which is printed directly on the top side of the cover glass 13. Under said black print 19, data lines (21, not visible) are led from the electronic angle sensor to the display housing 11 under the cover glass 13, wherein the not visible data lines open into an aggregate port 23, which represents the output interface 25.

[0120] The indicator instrument 1 with an electronic angle sensor 17 is shown in a sectional, perspective view in FIG. 3. The electronic angle sensor 17 comprises a display element 27, which has an indicator element 29.

[0121] The indicator element 29 of the display element 27 points to a switching point 30.

[0122] In the present embodiment, the indicator element 29 is configured as a triangle embossed into the display element 27; however, it may be configured in any other form, for example, as a point formed on the actuating element 42.

[0123] The electronic angle sensor 17 comprises an upper housing part 31 and a lower housing part 33. Both housing parts 31, 33 are connected to one another, for example, locked into position, wherein a connection point 35 is led through an opening of the cover glass 13. The opening of the cover glass 13 is not visible in FIG. 3.

[0124] An actuating element 42, which can be configured as either movable separately and in relation to the housing part, or as a monolithic part of the upper housing part 31, is provided on the side of the upper housing part 31 facing the user.

[0125] The actuating element 42 may be configured to signal both optically and haptically the functions of the actuating element 42 that are available.

[0126] The two housing parts 31, 33 of the electronic angle sensor 17 form an interior space 37 of the angle sensor 17, in which the sensor unit 39 and the analysis unit 41 are located. Both the sensor unit 39 and the analysis unit 41 are configured as integrated switching circuits 43.

[0127] The sensor unit 39 is located in the lower housing part 33 of the angle sensor 17, the lower housing part 33 being opened on its side pointing in the direction of the indicator 7 such that the sensor unit 39 pointing in the direction of the indicator 7 closes the interior space 37 of the angle sensor 17. The sensor unit 39 is thus visible and accessible from outside of the angle sensor 17.

[0128] There is a measuring distance 45 between the sensor unit 39 pointing in the direction of the indicator 7 and the indicator 7 of the indicator instrument 1.

[0129] FIG. 4 show a capacitive electronic angle sensor 17. This comprises the upper housing part 31, the lower housing part 33, which is shown as semitransparent in FIG. 4, the output interface 25, which is configured in the form of two data lines 21, the sensor unit 39 as well as the cover glass 13, which has the black print 19.

[0130] A sealing element 47 between the upper housing part 31 and the cover glass 13 is provided at the connection point 35, which is located in the not visible opening of the cover glass 13. The sealing element 47 is advantageous to reduce or even to prevent a penetration of dust and fluids behind the cover glass 13.

[0131] Further, individual measuring sectors 49 of the sensor unit 39 are shown. These measuring sectors extend circumferentially about an axle mount 51. The axle mount 51 is used to receive an end of the indicator axis 15 protruding beyond the indicator 7 (see FIG. 1), without the indicator axis 15 contacting the angle sensor 17.

[0132] The axle mount 51 also makes it possible to set the measuring distance 45 between the indicator 7 and the sensor unit 39 independently of the axle projecting length 53.

[0133] The measuring sectors 49 are configured as flat electrodes in the embodiment of the electronic angle sensor 17 shown in FIG. 4. The measured capacity of the electrodes 50 is dependent on whether a dielectric material is located in the vicinity of the electrodes 50 and how large the overlap between the indicator and the surface of the electrodes 50 is.

[0134] The indicator axis (not shown in FIG. 4), which is symbolized here by an axis of rotation 55, runs in the mounted state 53 centrally through the axle mount 51. In the mounted state 53, the axis of rotation 55 shown in FIG. 4 is identical to the axis of rotation 55 shown in FIG. 1.

[0135] The measuring sectors 49 have a length 1 and a width b. The length 1 extends in the radial direction and the width b in the circumferential direction. The achievable angular resolution of the sensor unit 39 is dependent on how many measuring sectors 49 are located in an angle segment. If the measuring sectors 49 are arranged around the entire circumference, i.e., over an angle of 2, then the angular resolution results from the quotient of 2 and the number N of measuring sectors 49.

[0136] The achievable angular resolution of the sensor unit 39 is thus dependent on the width b of the measuring sectors 49, on the distance 59 between the measuring sectors 49 as well as on the radial distance r of the measuring sectors 49 from the axis of rotation 55.

[0137] FIG. 5 shows an inductive electronic angle sensor 17. This comprises essentially the same elements as the capacitive electronic angle sensor 17 from FIG. 4.

[0138] The sensor unit 39 of the exemplary embodiment of the electronic angle sensor 17 shown in FIG. 5 comprises an inner coil ring 61 and an outer coil ring 63.

[0139] Both coil rings 61, 63 comprise a plurality of single coils 65, each of which represents a measuring sector 49 of the inductive electronic angle sensor 17.

[0140] The single coils 65 preferably have at least one winding.

[0141] The single coils 65, which are provided on different coil rings 61, 63 and are adjacent, have an angular offset 67, which is shown, in the example of the single coils 65a and 65b in FIG. 5. The angular offset 67 is selected, so that the measured values of the single coils 65a and 65b are phase-shifted to one another by 90. This arrangement increases the angular resolution.

[0142] Both the measuring sectors 49 configured as electrodes 50 in FIG. 4 and as single coils 65 in FIG. 5 may be part of the integrated switching circuit 43.

[0143] With reference to FIG. 6, the setting of the switching point 30 and the design of the indicator image 77 shall be explained on the basis of a configuration not limiting the present invention.

[0144] The indicator instrument 1 is shown with an indicator 7 in a first indicator position 7a. The indicator instrument 1 can be used for temperature measurement in the embodiment shown in FIG. 6, wherein a process is monitored, the temperature of which is approximately between 32 C. and 65 C. and the minimum temperature of about 32 C. may not be dropped below.

[0145] FIG. 6 likewise shows the display element 27 as well as the sensor unit 39 with forty electrodes 50 of a capacitive electronic angle sensor 17 as an example. The housing parts of the angle sensor 17 are not shown in order to illustrate the position of the individual electrodes 50 to the indicator 7.

[0146] The display element 27 displays the switching point 30 with its indicator element 29.

[0147] In the embodiment shown, the indicator 76 has a recess 71 and two webs 73, which converge in the indicator tip 75 and enclose the recess 71.

[0148] At the opposite end of the indicator, this [indicator] has a counterbalancing end 76, which has the form of a dovetail and thus overlaps more electrodes 50 than the individual webs 73 of the indicator tip 75.

[0149] FIG. 6a likewise shows a first indicator image 77a. The first indicator image 77a is composed of the individual signals S of the respective electrodes 50 in arbitrary units. These signals S are plotted over a running index n of the electrodes 50.

[0150] Depending on the configuration of the indicator in the area of the sensor unit, a different indicator image 77 is obtained as a result.

[0151] In the example shown, the running index n=1 is assigned to the electrode 50a, the running index n=20 to the electrode 50b and the running index n=40 to the electrode 50c. Said assignment is only selected as an example to illustrate the principle of the indicator image 77.

[0152] In the first indicator position 7a, the indicator 7 overlaps the electrodes 50 such that the measured capacity of the individual electrodes 50 plotted over the running index n of the electrodes 50 produces the first indicator image 77a. In this case, the capacity is plotted as signal S in arbitrary units.

[0153] It can be clearly seen from the first indicator image 77a that it is not possible to conclude the angular position of the indicator 7 by means of an analysis of the maximum value and of the weighted maximum value. In the case of a weighting during the measurement, the counterbalancing end 76 overlapping the plurality of electrodes 50 would suggest an erroneous display of about 100 C.

[0154] If the temperature of about 32 C. shall be fixed as a switching point 30 of the minimum temperature in the example of FIG. 6 shown, then the display element 27 is correlated with the indicator 7.

[0155] In another embodiment, it may be sufficient to correlate the indicator element 29, which can be formed on the upper housing part 31, with the indicator 7. The indicator element 29 may be, for example, a point, or else any other form of a marking on the upper housing part 31.

[0156] This correlation can take place in any desired indicator position, i.e., not necessarily in the indicator position 7a shown, since the sensor unit 39 and thus the entirety of the electrodes 50 are connected nonrotatably to the display element 7 and thus the electrode 50a always lies above the recess 71 of the indicator 7 in case of correlation of the display element 27 with the indicator 7.

[0157] By actuating the actuating element (not shown), the first indicator image 77a can be stored in a memory, not shown.

[0158] After inputting the first indicator image 77a, the display element 27 is rotated to the switching point 30. In FIG. 6, this is the indicator position, which corresponds to a temperature of about 38 C.

[0159] If the temperature rises to about 88 C., then the indicator 7 is in a second indicator position 7b shown by a dotted line. In the second indicator position 7b, the indicator overlaps other electrodes 50 of the sensor unit 39, since the position of the sensor unit 39 was not changed in relation to the indicator instrument 1.

[0160] In the second indicator position 7b, a second indicator image 77b is detected.

[0161] FIG. 6b shows a second indicator image 77b. Since the indicator 7 was rotated by 90 from the first indicator position 7a to the second indicator position 7b, this second indicator image 77b is offset by ten electrodes 50 in relation to the first indicator image. The second indicator image 77b is likewise shown in FIG. 6.

[0162] If the temperature drops to 38 C. during the operation, then the first indicator image 77a is obtained only precisely upon reaching the indicator position, which corresponds to a temperature of 38 C.

[0163] If this is the case, then the analysis unit, not shown, will detect the reaching of the switching point 30 and bring about the output of a switching point signal, as described above.

[0164] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.