Daimler-benz Ag

Werner Forkel

Edmund Schiessle

A fiber optic sensor for the detection of the position or movement of a component, for example the speed of rotation of a shaft, is described, which is particularly suitable for use in a coarse environment. The optical modulator of the sensor comprises a permanent magnet and a modulator part, the permanent magnet and/or the modulator part being mounted so as to be movable relative to a transmitting and receiving light guide. A change caused by a movement generator, for example the shaft, causes a change in the course of the field lines emanating from the permanent magnet which causes a corresponding movement of the modulator part, whereby a greater or lesser proportion of the light radiated out by the transmitting optical fiber is modulated by the modulator part and is transmitted into the receiving optical fiber. The corresponding modulation of the light according to the intensity, color or polarization is then utilized as a measure of the movement or position of the component, and appropriately analyzed.

Fiber optic sensor with an optical modulator having a permanent magnet

A device is provided for the indirect contactless electrical measuring of short distances, particularly for measuring the stroke and/or the position of nozzle needles for injection nozzles of internal combustion engines. A coil having a solid core of a soft-magnetic alloy is used as magnetic field sensor and a low-mass permanent magnet. The permanent magnet is rigidly connected to a moving control element. The nozzle needle is fixed to the control element. Movement of the permanent magnet in relation to the coil causes a change in the magnetic flux density in the core of the coil and, via the nonlinear function B=f(H) of the mangetization curve, effects a change in the dynamic permeability and consequently in the inductance of the coil. The change in inductance of the coil is converted by a suitable electronic evaluating circuit into a path-analogue signal to determine the distance between the fixed coil and the movable permanent magnet. Thus, movement of the nozzle needle which is fixed in relation to the permanent magnet can be precisely monitored.

Device for the indirect contactless electrical measuring of short paths

A device for detecting the speed of rotation and/or an angle of rotation of a shaft having a motion transmitter which rotates with the shaft, the device consisting of a magnetic-field-dependent sensor which receives a signal from the motion transmitter. A permanent magnet is arranged in the vicinity of the sensor with an evaluating circuit, the sensor being an integrating component of the evaluating circuit. The arrangement of the permanent magnet with respect to the sensor and of the permanent magnet and sensor with respect to the motion transmitter, on the one hand, and the construction of the sensor as a saturable-core probe (fluxgate effect), on the other hand, make it possible to detect even very slow rotational movements such as occur, for example, with antiblocking systems or forward drive control systems in motor vehicles.

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Stuttgart, Germany

Werner Forkel