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

Patent metadata

Field	Value
Publication number	US-9803996-B2
Application number	US-201314410442-A
Country	US
Kind code	B2
Filing date	Jun 17, 2013
Priority date	Jun 28, 2012
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

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.

First claim

The invention claimed is:

1. A system for ascertaining a number of revolutions of a rotationally mounted shaft, comprising:
a permanent magnet connected to the shaft in a torsionally fixed manner;
a microgenerator situated in an operative connection with the permanent magnet, wherein a signal voltage generated by the microgenerator is supplied to an energy buffer, wherein the microgenerator is adapted to operate in an energy-autonomous manner;
a memory device for storing the number of revolutions supplied from the energy buffer;
a counting logic device, wherein:
the signal voltage of the microgenerator is supplied to the counting logic device, and
the counting logic device is supplied from the energy buffer and is connected to the memory device for reading out a respective old numerical value of the revolutions and for storing a respective newly ascertained numerical value of the revolutions,
the memory device is at least one of designed for long-term stability and designed in FRAM technology, and

an angle sensor for ascertaining a rotational position of the shaft and connected via a signal line to a computer, wherein:
the computer analyzes a voltage applied at the energy buffer,
the computer one of (1) has an arrangement for analyzing the voltage applied at the energy buffer, and (2) is connected to the arrangement for analyzing the voltage,
a voltage characteristic occurring at the energy buffer is used for ascertaining a value of a characteristic quantity corresponding to a state variable of the voltage characteristic,
an error signal is triggered when a critical measure corresponding to a predefined measure of a deviation of a value from an average value is exceeded,
the average value is determined from corresponding values of characteristic quantities determined previously, and
the measure is a function of a statistical variable or a higher moment of a distribution function.

2. The system as recited in claim 1 , further comprising a rectifier, wherein:
the energy buffer includes a capacitor, and
the signal voltage is supplied via the rectifier to the capacitor.

3. The system as recited in claim 1 , wherein the angle sensor ascertains the rotational position as an angle of rotation.

4. The system as recited in claim 1 , wherein the computer is connected to the arrangement for analyzing the voltage via a data exchange link.

5. The system as recited in claim 1 , wherein the microgenerator is a Wiegand wire or includes a Wiegand wire.

6. The system as recited in claim 1 , wherein the microgenerator is a pulse wire.

7. The system as recited in claim 1 , further comprising a signal line for the exchange of data that is disposed between the computer and the memory device.

8. The system as recited in claim 1 , wherein the angle sensor and the computer are supplied by one voltage source.

9. The system as recited in claim 8 , wherein the counting logic and the energy buffer are not supplied from the voltage source.

10. The system as recited in claim 1 , wherein the angle sensor includes one of:
a Hall-effect sensor that is mechanically linked to the permanent magnet, and
a resolver connected to one of the shaft and an incremental encoder.

11. A method for ascertaining a rotational speed of a rotationally mounted shaft, comprising:
connecting a permanent magnet to the shaft in a torsionally fixed manner;
generating a signal voltage by a microgenerator situated in an operative connection with the permanent magnet, wherein the microgenerator operates in an energy-autonomous manner;
supplying the signal voltage to an energy buffer;
supplying a memory device from the energy buffer, the memory device storing currently ascertained numerical values of revolutions of the shaft, wherein the memory device is at least one of designed for long-term stability and designed in FRAM technology; and
supplying the signal voltage of the microgenerator to a counting logic device, which is supplied from the energy buffer and is connected to the memory device for reading out respective old numerical value of the revolutions and for storing respective newly ascertained numerical value of the revolutions, wherein:
the rotational angle of the shaft is determined using an angle sensor and forwarded to a computer,
the computer analyzes the signal voltage applied at the energy buffer, while taking an angle of rotation detected by the angle sensor into account,
a voltage characteristic occurring at the energy buffer is used for ascertaining a value of a characteristic quantity corresponding to a state variable of the voltage characteristic,
an error signal is triggered when a critical measure corresponding to a predefined measure of a deviation of a value from an average value is exceeded,
the average value is determined from corresponding values of characteristic quantities determined previously, and
the measure is a function of a statistical variable or a higher moment of a distribution function.

12. The method as recited in claim 11 , wherein:
the energy buffer includes a capacitor, and
the signal voltage is supplied via a rectifier to the capacitor.

13. The method as recited in claim 11 , wherein:
the statistical variable is a standard deviation, and
the measure corresponds to a statistical moment multiplied by a factor, the moment being the standard deviation.

14. The method as recited in claim 11 , wherein for a pulse-shaped voltage characteristic occurring at the energy buffer, a value of a characteristic quantity, especially a state variable, of a voltage curve is ascertained from the voltage characteristic that occurs at the energy buffer, and an error signal is triggered when a critical value is not attained or exceeded.

15. The method as recited in claim 11 , wherein for a pulse-shaped voltage characteristic occurring at the energy buffer, a value of a characteristic quantity, especially a state variable, of a voltage curve is ascertained from the voltage characteristic that occurs at the energy buffer, an average value of the characteristic quantity is ascertained for all pulses, or another statistical variable, such as the standard deviation or a higher distribution moment, and an error signal is triggered when the average value or the value of the other statistical variable drops below or exceeds a critical value.

16. A method for ascertaining a rotational speed of a rotationally mounted shaft, comprising:
connecting a permanent magnet to the shaft in a torsionally fixed manner;
generating a signal voltage by a microgenerator situated in an operative connection with the permanent magnet, wherein the microgenerator operates in an energy-autonomous manner;
supplying the signal voltage to an energy buffer;
supplying a memory device from the energy buffer, the memory device storing currently ascertained numerical values of revolutions of the shaft, wherein the memory device is at least one of designed for long-term stability and designed in FRAM technology; and
supplying the signal voltage of the microgenerator to a counting logic device, which is supplied from the energy buffer and is connected to the memory device for reading out respective old numerical value of the revolutions and for storing respective newly ascertained numerical value of the revolutions, wherein:
the rotational angle of the shaft is determined using an angle sensor and forwarded to a computer,
the computer analyzes the signal voltage applied at the energy buffer, while taking an angle of rotation detected by the angle sensor into account,

a pulse-shaped voltage characteristic occurring at t

Assignees

• Sew Eurodrive Gmbh & Co Kg

Inventors

• Simon Olaf
• Meyrowitz Gunnar

Classifications

• G01P3/4815

  using a pulse wire sensor, e.g. Wiegand wire · CPC title

• G01D3/08

  with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown · CPC title

• G01R19/00

  Arrangements for measuring currents or voltages or for indicating presence or sign thereof (G01R5/00 takes precedence; for measuring bioelectric currents or voltages A61B5/24) · CPC title

• G01D9/005 Primary

  Solid-state data loggers · CPC title

• G01D5/142 Primary

  using Hall-effect devices (measuring magnetic variables using Hall-effect or other galvanomagnetic devices G01R33/06) · CPC title