System for ascertaining the number of revolutions of a rotationally mounted shaft, and method for ascertaining the number of revolutions of a rotationally mounted shaft, a permanent magnet being connected to the shaft in a torsionally fixed manner, the signal voltage generated by a microgenerator situated in an operative connection with the permanent magnet being supplied to an energy buffer, especially via a rectifier to a capacitor, a memory device for storing the number of revolutions being supplied from the energy buffer, the signal voltage of the microgenerator in particular being supplied to a counting logic device, which is supplied from the energy buffer and is connected to the memory device for reading out the respective old numerical value of the revolutions and for storing the respective newly ascertained numerical value of the revolutions.

A magnet for detection mounted on a rotating shaft rotating about a rotation axis, and a detector disposed opposite to the magnet for detection to detect rotation of the rotating shaft are included. The detector includes a multi-layer circuit board, a recessed groove that is provided in an interlayer of the circuit board, has a center on an extension of the rotation axis, and is orthogonal to the rotation axis, a combined magnetic wire incorporated in the recessed groove and exhibiting a large Barkhausen effect, and a pickup coil formed of wiring conductors on the circuit board and a conductor with which through holes are filled, to surround the combined magnetic wire.

The rotation sensing device comprises a magnet, magnetic sensors, and yokes, which are secured to the base and control the magnetic flux of the magnetic field formed by the magnet; each magnetic sensor comprises a magnetic wire, a coil, and a bobbin; each yoke comprises a left yoke piece and a right yoke piece partially covering the left portion and the right portion of the magnetic sensor; the left yoke piece has a left front plate portion, the left front plate portion, which extends linearly from the front of the left portion of the bobbin, which is to the left of the section where the coil is provided, all the way to the front of the coil, and is inclined with respect to the direction of extension of the magnetic wire such that the right end thereof is located rearwardly of left end thereof.

A position sensor is configured to use a Wiegand wire, position magnet(s) and a reset magnet in which changes in polarization of the Wiegand wire caused by the position magnet(s) can be reset by the reset magnet. The position magnet(s), which can move in relation to the Wiegand wire, can have relatively stronger magnetic flux densities, and the reset magnet, which can be fixed in relation to the Wiegand wire, can have a relatively weaker magnetic flux density. When the position magnet(s) are proximal the Wiegand wire, the relatively stronger position magnet(s) overcome the reset magnet to cause a change in polarization of the Wiegand wire which produces an electrical pulse which can be counted. However, when the position magnet(s) become distal to the Wiegand wire, the relatively weaker reset magnet can reset the polarization of the Wiegand wire to prepare for a next count. As a result, the total number of magnets required in the system can be reduced, and the probability of failing to reset the Wiegand wire can be lowered.

The rotation sensing device comprises a magnet, magnetic sensors, and yokes, which are secured to the base and control the magnetic flux of the magnetic field formed by the magnet; each magnetic sensor comprises a magnetic wire, a coil, and a bobbin; each yoke comprises a left yoke piece and a right yoke piece partially covering the left portion and the right portion of the magnetic sensor; the left yoke piece has a left front plate portion, the left front plate portion, which extends linearly from the front of the left portion of the bobbin, which is to the left of the section where the coil is provided, all the way to the front of the coil, and is inclined with respect to the direction of extension of the magnetic wire such that the right end thereof is located rearwardly of left end thereof.

A battery-free rotation detecting device includes a rotating carrier, a first magnetic element, a second magnetic element and at least one detection coil set. The rotating carrier can be assembled with a rotating element. The first magnetic element is disposed to the rotating carrier, and the second magnetic element is also disposed to the rotating carrier but spaced from the first magnetic element. The at least one detection coil set is located between the first magnetic element and the second magnetic element. The rotating carrier can be driven by the rotating element so as further to rotate the first magnetic element and the second magnetic element synchronously. The at least one detection coil set generates an electrical signal upon when a change of the magnetic field between the first magnetic element and the second magnetic element is detected.

A sensor device includes an excitation magnet which generates an alternating excitation magnetic field, an energy generator having a pulse wire module in which electric energy pulses are generatable via the alternating excitation magnetic field, at least one sensor element which senses a physical variable and which provides a sensor signal, an evaluation unit which evaluates the sensor signal, and a wireless data interface which is connected to the evaluation unit via a data connection. The at least one sensor element and the evaluation unit are each electrically connected to the energy generator and are suppliable with an electric energy thereby.

A magnetic-field sensor device includes at least two impulse wires, a coil assembly which radially surrounds the at least two impulse wires, the coil assembly defining a sensor element and a feedback element which generates an auxiliary magnetic field, an energy storage which is electrically connected to the coil assembly, a switching element which is electrically connected to the energy storage and to the feedback element, and a control unit which electrically controls the switching element.

The magnetic sensing portion 30 of the rotation sensing device comprises three magnetic sensors 31-33 and a substrate 45 for mounting these magnetic sensors, with each magnetic sensor comprising a magnetic wire 34 generating large Barkhausen effects, a coil 35, and a bobbin 36. The magnetic sensors are disposed on the substrate 45 such that the directions of extension of the magnetic wires 34 are parallel to the substrate 45, the magnetic sensing portion 30 is disposed on the outer periphery of the trackway of the magnetic field forming portions such that the directions of extension of the magnetic wires 34 are parallel to the axial direction of the rotary shaft 3, and the location of the magnetic wire installation portion 38 in the bobbin 36 of each magnetic sensor is configured such that the respective magnetic wires 34 of the three magnetic sensors are respectively equidistant from the rotary shaft 3.

A magnet-based rotary angle sensor system for detecting a shaft rotation. The magnet-based rotary angle sensor system includes a rotatable excitation unit which is mounted to a shaft for rotation therewith, and a static sensor unit. The rotatable excitation unit includes at least one excitation magnet. The static sensor unit detects an excitation-magnetic field generated by the at least one excitation magnet. The static sensor unit includes a first Wiegand sensor module and a second Wiegand sensor module which are arranged in a cross-shaped manner and axially spaced from each other.