DE9012171U1 - Non-contact measuring device for torque and/or angle of rotation - Google Patents

Description

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a · · 0002/Be/Be 15-08.1990 Oberkochen ZDGAR BZIER 7082

Contact-free measuring device for torque and/or angle of rotation

State of the art

The invention relates to a measuring device according to the type of Ha .^tansprue ,Iis.

Such a contact-free charging device for detecting a torque and/or an angle of rotation on a stationary or rotating shaft is known (EP 0 144 80J BI).

This known measuring device determines the torque acting on the shaft and/or the angle of rotation by which a given shaft section rotates by using the eddy current effect and assigns a concentric coil to two concentric bodies which consist of electrically conductive materials and whose common overlap area changes with increasing angle of rotation occurring between the two bodies. The two bodies are connected to the shaft at one end in a rotationally fixed manner and can change their common overlap area by having cutouts and the cutouts of one body forming windows for the spokes of the other body located between the cutouts.

3002/Be/BeG

15.08.1990 ~ ² ~

The relative rotation of the two bodies changes the material surface of the two bodies that acts on the measuring coil to generate the eddy current effect. The problem with this measuring device could be that the measuring coil must be operated with alternating voltage in order to utilize the eddy current effect. The resulting gyratory current effect means a power loss in the coil that needs to be measured. However, since the power is the product of current and voltage, and a phase shift between current and voltage occurs in the coil, the power is zero at every zero crossing of voltage and current. At a frequency of 50 Hz, this occurs 200 times per second. However, if the power is zero, no power loss occurs, i.e. nothing can be measured 200 times per second at 50 Hz. By boiling the average power, an accurate measurement is simulated, but an accurate measurement of the moment-time curve with any moment peaks that may occur is not possible. not possible. The invention is therefore based on the object of creating a non-contact measuring device for torque and/or angle of rotation which ensures continuous and simple but precise measurement.

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0002/Be/BeG

13.08.1990 - 3-

Advantage 1. &ogr; d_e r Kj[Xi &eegr; dun 'j :

The invention solves the features so characteristic of Au Cy a be ir.it don and has, compared to the known contact?; f > a MoSv-M icht'-JH'j the Vnrrpi 1 . ti &lgr; R dip ".ossuivj continuously rf ^r )] Jt-. and c' -.lit is more precise.

Depending on the type and application, measurement can be carried out using magnetic, optical, inductive or acoustic measurement methods.

The bodies are absolutely identical in principle ^{and can} , for example ^, be manufactured using casting technology with ^sufficient precision and in large ^numbers . The standardization achieved thereby contributes to the cost savings.

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0002/Be/BeG

15.08.1990 ~ ⁴ '

Drawing:

Examples of embodiments of the invention are shown in the drawing and explained in more detail in the following description.

Show Fs.

Fig.1: Measuring arrangement with two bodies (1,2) which have sawtooth-like profiles facing each other.

Fig. 2 : Measuring arrangement with concentric cylinders.

Fig. 3: Development profile of two bodies (1,2) with a sawtooth-like profile facing each other.

Fig.3a: as in Fig.3, but with indicated optical beam path for two different relative positions

Fig. 4: Development profile of two bodies (1,2) with a sawtooth-like profile facing away from each other.

Fig.4a: like Fig.4, but with indicated optical beam path for two different relative positions

Fiq.5 : Example of another possible development profile of the two bodies (1,2).

Fig.6 : like Fig.5 Fig.7 : like Fig.5

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0002/Be/BeG

15.08.1990 ~ ⁵ ~

Description of the execution -· examples:

The basic idea of the present invention is that in the case of two wedge-shaped bodies Fig. 1/1,2, which are concentrically connected around the width y cinyöü'", the relative material thickness and the relative air gap width between the bodies 1,2 are constant over long distances. When the two bodies 1,2 are rotated relative to one another, both the relative material thickness and the relative air gap width change.

For the sake of clarity, the functional principles of the various embodiments are explained using their development profiles.

Execution according to Fig.3 and Fig. 3a:

During a relative movement, the relative gap width between the two bodies 1,2 changes. At the same time, the relative material thickness also changes. It is advisable for the gradients of the inclined flanks to be equal in magnitude. This means that both the relative gap width and the relative material thickness are the same at every point.

If the bodies 1,2 are made of paramagnetic material, an externally applied magnetic field is strengthened or weakened when the relative position changes, depending on whether the relative air quality and the relative material thickness increase or decrease. This effect is independent of the position.

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•t*

0002/Be/BeG

15.08.1990 ~ ⁶ ~

For optical detection (Fig. 1a), the two bodies 1,2 are usually made of an optical material with a high refractive index.

J(J A ray of light penetrates body 1 in an axial direction. It is refracted at the angle F1 and changes direction. This direction remains ^the same until it hits the oblique surface of body 2 and is refracted again, so that it runs in an axial direction. When it exits from body 2 it has been parallel to its original direction. When the two bodies 1,2 move relative to each other it changes direction. si:.: the relative ^. alt-width and S'.rr.it the 'lie which places the light beam obliquely to its starting and ending directions.

This causes the amount of parallel shift to become larger or smaller.

/-.us implementation according to Fig. 4 and Fig. 4a: This arrangement is suitable for optical detection, whereby the relative material thickness is important here.

A ray of light falling from an axial direction onto body 1 is refracted at the oblique flank. With the new direction it passes through body 1,2, until it is refracted again at the oblique flank of body 2 when it emerges and continues parallel to its original direction. Depending on the relative thickness of the material, its parallel displacement will be larger or smaller.

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0002/Be/Se G

15.08.1990 -7-

Execution according to Fig.5, Fig.6 and Fig.7:

If the relative position of the two bodies 1,2 changes, the relative distance between two opposing flank pairs changes. While the relative distance decreases for one flank pair, it increases for the other to the same extent. A magnetic field applied from the outside would be strengthened between the flanks that are coming closer together and weakened between those that are moving away from each other. Since the strengthening and weakening of the magnetic field are not linearly related to the flank distance, their sum effectively results in a strengthening.

All features presented in the description, the claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims (9)

0002/Be/Be G 15.08.1990 EDGAR BEIER, 7082 Oberkochen Non-contact measuring device for torque and/or angle of rotation Protection claims: 1. Contact-free measurement for torque and/or angle of rotation on stationary or rotating shafts (2) with two bodies ( 1,2) which are concentric with the shaft, fastened to the shaft (3) with their respective end regions in a rotationally fixed manner and which can be rotated relative to one another, furthermore with a measuring system (4a,4b) which determines the torque and/or angle of rotation transmitted by the shaft (3) over a predetermined shaft section from the relative position of the two bodies (1,2) which changes with the angle of rotation, characterized in that the axial dimensions of both bodies (1,2) on at least one side in each case &iacgr; circumferential direction over at least a certain circumferential angle .continuously or abruptly change (Figs.3-7), or that the two bodies (1,7) are concentric cylinders, each having optical patterns (Fig.2), and that the axial dimensions of the optical patterns of both cylinders on at least one side in the circumferential direction change continuously or abruptly over at least a certain circumferential angle (Figs.3-7). /2 0002/Be/BeG 15.08.1990 -2- 2. Measuring device according to claim 1, characterized in that the two cor;?": ,1/2) r.ir have sawtooth-like profiles on the sides facing away from each other *.? have u;:l are bordered on the sides facing each other by concentric circular ring surfaces (Fig.4) 3. Measuring device according to claim 1, characterized in that the two bodies (1, 2) have sawtooth-like profiles only on the sides facing each other and are delimited by concentric circular ring surfaces on the sides facing away from each other (Fig. 2) 4. Measuring device according to claim 1, characterized in that each of the two bodies (1, 2) has sawtooth-like profiles on both sides (Fig. 5). 5 5. Measuring device according to one or more of claims 1 to 4, characterized in that at least one detection system (4a, 4b) detects the relative material thickness in the axial direction, which changes with the angle of rotation, and/or the changing relative gap width between the two bodies. 6. Measuring device according to one or more of claims 1 to 5, characterized in that the two bodies (1, 2) consist of an optical material. /1' 0002/Be/Br.G 15.08.1990 -3- "j 7. Measuring device ^according to one or more of claims 1 to 5, characterized in that the two bodies (1, 2) consist of a paramagnetic or ferromagnetic material. 8. Measuring device according to one or more of claims 1 to 6, characterized in that the boid'-n bodies (1,2) are concentric, nested cylinders made of an electrically non-conductive material and that they each have patterns 'Tj3' of an electrically conductive material "j'j ( t ig . 2 ). 9. Measuring device according to one or more of claims 1 to 5, characterized in that the two bodies (1, 2) consist of an electrically conductive material.