DE1249575B - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

301 ρ

Gold

Jueutsche Kl .: 42 ο - 13/10

Number: 1 249 575

File number: S 90125 IX b / 42 ο

Filing date: March 20, 1964

Opened on: September 7, 1967

The invention relates to an arrangement for the simultaneous measurement of distance and speed rotating body, in which in moving, conductive, non-magnetic metal bodies, in particular Drums or disks, eddy currents proportional to the speed of fixed magnets are generated whose magnetic field penetrates a Hall generator, with two parallel permanent magnets arranged with the same magnetization direction on a soft magnetic base plate and the pole faces of the permanent magnets opposite the base plate each with a soft magnetic plate are provided so that there is an air gap between these plates in which a Hall generator is located in the magnetic plane of symmetry of the permanent magnets.

An arrangement for measuring speed by means of eddy currents is already known in which a Hall generator is arranged stationary relative to the magnet so that it is separated from the magnet by the eddy currents resulting field is enforced. With this arrangement, however, it is possible without additional integrating means do not perform a direct electrical displacement measurement.

Furthermore, a contactless signal transmitter with contactless actuation by iron parts is known using a hall generator. This signal transmitter has two permanent magnets on one magnetically soft iron plate. With this plate, the signal transmitter is against at the place of installation existing iron parts are shielded from below, which could disturb the field symmetry. aside from that the iron plate helps to increase the sensitivity of the signal transmitter. To be as large as possible To achieve a bundling effect for the magnetic flux and thus a high display sensitivity, the Hall generator is located in the air gap between two pieces of soft iron in the magnetic plane of symmetry of the arrangement. Taper the soft iron pole pieces towards the hall generator. This eliminates the magnetic shunt between the pieces of soft iron kept small.

The present invention has for its object to provide an arrangement with the opposite the known arrangements without additional integrating means at the same time speed and Distance measurements can be carried out. To this end, the invention is on both sides of the Hall generator each arranged an L-shaped soft magnetic sheet and in the movable non-magnetic metal body attached at least one permanent magnet.

Arrangement for the simultaneous measurement of displacement
and speed of rotating bodies

Applicant:

Siemens Aktiengesellschaft, Berlin and Munich, Erlangen, Werner-von-Siemens-Str. 50

Named as inventor:

Dr. rer. nat. Friedrich Kuhrt,

Dr. rer. nat. Julius Brunner, Nuremberg

^

Only through this arrangement of the L-shaped soft magnetic sheets is it possible to control the magnetic flux of the permanent magnet located in the movable non-magnetic metal body

Catch ao and bring it to action on the Hall generator in order to cause a counting pulse. This measure ensures that the known arrangements for speed measurement by means of eddy currents and Hall generators can now be used simultaneously for distance measurement.

In the following, the invention will be explained with reference to the drawing and an exemplary embodiment explained in more detail. It shows

F i g. 1 limits the basic principle of the arrangement according to the invention in a schematic representation on the speed measurement,

Fig. 2 shows an embodiment of the arrangement according to the invention for simultaneous speed and distance measurement.

F i g. 3 a graphical representation of the course of the generated with the arrangement according to the invention Signal voltage.

In Fig. 1 the known basic principle of speed measurement is shown schematically. With 11 are two parallel permanent magnets with the same magnetization direction, with 12 is a soft magnetic base plate, with 13 a Hall generator, z. B. a ferrite Hall generator, which is located in the air gap between two soft magnetic plates 14 , with 15 a non-magnetic movable metal body, for. B. a disc or drum made of copper, with 16 and 17 denotes the field lines of the magnetic fields of the two permanent magnets. 18 and 19 indicate the direction of the eddy currents in the non-magnetic metal body; with 20 the course of the field lines of the eddy current magnet

709 640/120

Claims (2)

shown in the field. If a relative movement occurs between the non-magnetic metal body 15 and the magnet 11 z. B. in the direction of the arrow, an electrical voltage is generated in the body 15. Under the action of this tension, eddy currents occur in the body 15, the direction of which is indicated by 18 and 19, respectively. The eddy currents in turn result in a magnetic field, the field lines of which are represented by 20. This magnetic field is proportional to the speed of the moving body. The magnetic flux of the eddy current field penetrates the Hall generator 13, which emits a voltage proportional to the speed. In FIG. 2, the arrangement according to the invention for simultaneous speed and distance measurement is shown schematically in an exemplary embodiment. With 21 and 22 permanent magnets, with 23, 24 and 25 soft magnetic pieces, with 26 a Hall generator, with 27 and 28 L-shaped soft magnetic sheets and with 29 a permanent magnet, which is located in the non-magnetic metal body. The metal body is not shown in the drawing for the sake of clarity. Only when this permanent magnet is above the Hall generator is the magnetic flux emanating from the permanent magnet 29 picked up by the L-shaped catch pieces and passed through the semiconductor layer. In addition to the voltage proportional to the speed, the Hall generator now emits a voltage pulse once per revolution, the polarity of which is opposite to that of the voltage proportional to the speed (selection of the polarity of the magnet 29) and the magnitude of which exceeds the maximum value of the voltage proportional to the speed. The Hall voltage then runs accordingly, as shown in FIG. 3 is shown. The path 5 covered by the non-magnetic disk or drum is shown on the abscissa and the voltage Uti, which is proportional to the speed, is shown on the ordinate. The mean value of the voltage proportional to the speed can be displayed using an appropriate instrument, e.g. a moving-coil instrument. The negative pulse can be generated through a simple amplifier, e.g. B. transistor amplifier, amplified and to operate the odometer, z. B. be used as an odometer on motor vehicles. The arrangement according to the invention is suitable for measuring the speed and distance on rotatingly moving bodies. Patent claims: 1. Arrangement for the simultaneous measurement of path and speed of rotating bodies, in which in moving, conductive, non-magnetic metal bodies, in particular drums or disks, eddy currents proportional to the speed are generated by stationary magnets, the magnetic field of which penetrates a Hall generator, with two parallel permanent magnets with the same magnetization direction arranged a soft magnetic base plate and the base plate opposite pole faces of the permanent magnets are each provided with a soft magnetic plate, so that there is an air gap between these plates in which a Hall generator is located in the magnetic plane of symmetry of the permanent magnets, characterized in that on both sides of the Hall generator an L-shaped soft magnetic sheet (27, 28) is arranged and that in the movable non-magnetic metal body at least one permanent magnet (29) is attached (Fig. 2). 2. Arrangement according to claim 1, characterized in that a ferrite Hall generator is used is. Considered publications:
German Auslegeschrift No. 1147 787;
"Elektrotechnische Zeitschrift", Ed. A (ETZ-A), 1. 83, issue 11 of May 21, 1962, pp. 367 to 372. 1 sheet of drawings 709 640/120 8.67 © Bundesdruckerei Berlin