Sensor device

Abstract

A method for producing a measurement value transmitter for a sensor device includes providing a magnetic body, providing a coil configured to be supplied with a current, and shaping the coil into a helical winding with an internal diameter that is greater than an outer contour of the magnetic body. The winding is shaped such that the pitch of the winding changes at least in some sections when viewed along the longitudinal extension of the winding. The method further includes arranging the magnetic body within the coil, in particular coaxially to the coil, and supplying the coil with a current so as to magnetize the magnetic body in order to produce the measurement value transmitter.

Claims

1. A method for producing a measurement transducer for a sensor device with a magnetic body and a coil configured to be supplied with current, the method comprising: forming the coil into a helical winding with an inner diameter that is greater than an outer contour of the magnetic body, the winding formed to have a gradient that changes at least in some sections when viewed in the longitudinal extension of the winding; arranging the magnetic body within the coil; supplying current to the coil to permanently magnetize the magnetic body as the measurement transducer; and removing the permanently magnetized measurement transducer from the winding.

2. The method as claimed in claim 1, wherein the winding is formed such that the gradient changes continuously within at least one section.

3. The method as claimed in claim 1, wherein the winding is formed to have a constant gradient at least in some sections.

4. The method as claimed in claim 1, wherein the winding is formed to have at least two sections with different constant gradients.

5. The method as claimed in claim 1, wherein the winding is formed to have at least one clamped section within which the gradient of the coil is equal to zero.

6. The method as claimed in claim 5, wherein the clamped section is formed at an end region of the winding or the magnetic body, or in a region spaced apart from the end region.

7. The method as claimed in claim 5, wherein the clamped section is formed between two sections of the winding with a predefined gradient.

8. The method as claimed in claim 1, wherein the arranging of the magnetic body within the coil includes arranging the magnetic body coaxially within the coil.

9. The method as claimed in claim 1, wherein the forming of the coil into the helical winding includes forming a first winding section having a first gradient, a second winding section having zero gradient, and a third winding section having a second gradient that is different from the first gradient.

10. The method as claimed in claim 9, wherein the first gradient and the second gradient are both constant.

11. The method as claimed in claim 10, wherein the first gradient and the second gradient run in the same direction.

12. The method as claimed in claim 1, wherein the supplying of the current to the magnetic body includes energizing the winding such that the magnetization or magnetic field alignment of the magnet body extends in a helical or screw shaped pattern along the magnetic body.

13. A device for producing a measurement transducer for a sensor device, comprising: a magnetic body configured to be permanently magnetized as the measurement transducer; a coil formed into a helical winding with an inner diameter that is greater than an outer contour of the magnetic body; and an energy source configured to supply current to the coil so as to permanently magnetize the magnetic body such that the magnetic body becomes the measurement transducer, wherein the winding is formed to have a gradient that varies at least in some sections when viewed in a longitudinal extension of the winding.

14. The device as claimed in claim 13, wherein the helical winding includes a first winding section having a first gradient, a second winding section having zero gradient, and a third winding section having a second gradient that is different from the first gradient.

15. The device as claimed in claim 14, wherein the first gradient and the second gradient are both constant.

16. The device as claimed in claim 15, wherein the first gradient and the second gradient run in the same direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following the disclosure will be explained in further detail by reference to the drawings. Shown are:

(2) FIG. 1 an advantageous sensor device in a simplified representation and

(3) FIG. 2 the production of an advantageous measurement transducer of the sensor device in a simplified representation.

DETAILED DESCRIPTION

(4) FIG. 1 shows a simplified sectional view of a sensor device 1, which has a measurement transducer 2 that can be displaced in a housing 3. The measurement transducer 2 has a cylindrical magnetic body 4, which has a circular cross section and, in particular, is produced from an isotropic magnetic material, and is arranged to be displaceable in its longitudinal extension or axially in the housing 3, as shown by a double-headed arrow 5. In addition, a measuring point 6 is provided on the housing 3, by means of which a magnetic field of the measurement transducer 2 can be detected. To this end the measuring point 6 has one or more sensors for detecting magnetic fields. In particular, the sensors are implemented as Hall sensors.

(5) The measurement transducer 2 also has a magnetization 8, which is designed to run in a helical pattern on the magnetic body 4 or extend over the magnet body 4 in the shape of a helix. In this regard, the magnetization 8 has a gradient which extends over at least some sections of the length of the magnetic body 4. The gradient in this case changes continuously or discontinuously, viewed in the longitudinal extension of the magnetic body.

(6) In accordance with the present exemplary embodiment of FIG. 1 it is provided that the magnetization 8 has a plurality of sections I, II and III, in which the magnetization 8 has different gradients. It is envisaged in this case that the gradient in section I is less than the gradient in section III, and that in section II the gradient is equal to zero, so that a so-called clamped range is formed, within which a displacement of the measurement transducer 2 does not lead to any change in the measurement. In each of sections I and III, the gradient is designed to be constant.

(7) With the advantageous sensor device 1, highly accurate measurements can be made, wherein the sensitivity of the sensor device 1 can be adjusted differently over different displacement path sections by means of the respective gradient, and clamped regions (section II) can also be simply produced.

(8) In the following, the production of the magnetic body 4 will be described.

(9) In this connection, FIG. 2 shows an enlarged representation of a device 10 for producing the measurement transducer 2. The measurement transducer 2 and/or the magnetic body 4 is apparent from the figure.

(10) In accordance with the exemplary embodiment shown, the magnetization 8 is produced using a coil 9 of the device 10 formed by a winding wire, which is arranged coaxially to the magnetic body 4 to produce the magnetization of the magnetic body 4.

(11) The device 10 also preferably has a mounting device (not shown here), which is designed for the mounting and alignment of the magnetic body 4 within the winding, so that, for example, a physical contact between the winding and the magnetic body 4, or a central arrangement and orientation of the magnetic body 4 relative to the coil 9 is ensured. In particular, the mounting device is designed to move the magnetic body 4 into and out of the coil 9 in the direction of its longitudinal extension.

(12) The device 10 also has an energy source 11 which can be connected to the coil 9, in order to supply this with current for producing the measurement transducer 2. If the coil 9 is supplied with current, then across the winding wire into which the current is injected a north pole N is produced, and below it a south pole S. Due to physical principles, each pole N, S has a full-valued antipole on the reverse outer surface of the magnetic body 4.

(13) In order to obtain the previously described course of the helical magnetization of the magnetic body 4, the coil is shaped to form a helix-shaped winding, which has a plurality of sections I, II and III in which different gradients are formed, corresponding to the gradients of the magnetic body 4 described in relation to FIG. 1, as shown in FIG. 2.

(14) Once the magnetization 8 has been produced, its pattern corresponds to the helical pattern of the coil 9, so that the magnetization 8 or its magnetic field orientation also extends in a helical or screw-shaped pattern along the magnetic body 4. The coil 9 is then removed and the magnetic body 4 is installed in the housing 3.

(15) If this measurement transducer 2 is now moved in a linear manner, in accordance with arrow 5, and at the measurement point 6 which is stationary with respect to it, the resulting angles and/or individual components of the magnetic flux density or magnetic field of the measurement transducer 2 are measured by means of the sensor 7, it is possible, in all three spatial directions in accordance with the coordinate system shown in FIG. 2, to detect a more or less sinusoidal change in all three flux density components.

(16) The combination of any two of the three measured flux density components leads in most cases to at least two continuous arctangent information values. There are two continuous output signals produced, which in combination may increase the accuracy and robustness of the measurement signal.

(17) Due to the advantageous gradient of the helical or screw-shaped magnetization 8, which optionally changes along the magnetic body 4, unique information or a unique spatial angle can be detected, even beyond a magnetic angle of 360°, by means of which the displacement position of the magnetic body 4 or of the measurement transducer 2 is unambiguously identifiable.

(18) The gradient of the magnetization 8 is preferably chosen in such a way that it is at its lowest at the point where the highest measurement accuracy is required, so that at this point a displacement of the transducer 2 relative to the measuring point 6 has the highest resolution accuracy with respect to the measurement signal, and therefore the highest measurement sensitivity. This is recommended for sensor applications in which one measurement range must be more accurate than other ranges.

(19) In this case it is also imaginable to design a differential measurement principle with two measuring points 6, because then the difference signal is largest where the gradient of the magnetization 8 is ideally of similar size to the distance between the two measuring points 6.

(20) Conveniently, the sensor device 1 has a control unit, not shown here, or at least a microcontroller, which monitors the output signals of the sensors 7 to determine the position of the measurement transducer 2 with respect to the stationary or housing-fixed measurement point 6.

(21) Advantageously, the constant or changing gradient extends within a limited section viewed in the longitudinal direction of the magnetic body or the coil 9. As shown in FIG. 2, sections of the coil 9 can also extend with a gradient equal to zero, so that the angle of rotation of the magnetic field of the magnetic body 4 in this so-called clamped region 12 does not change. The clamped region 12 can be arranged between two coil sections with a predetermined constant or varying gradient, as shown in the present exemplary embodiment, or else in one or both of the end regions of the magnetic body 4.