Electricity: measuring and testing – Magnetic – Displacement
Reexamination Certificate
1998-09-04
2001-05-22
Oda, Christine K. (Department: 2862)
Electricity: measuring and testing
Magnetic
Displacement
C324S207250, C340S870320
Reexamination Certificate
active
06236199
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an inductive angle sensor with a stator element, having an exciting coil with a periodic AC voltage applied thereto and several receiving coils, and with a rotor element that affects a strength of inductive coupling between the exciting coil and receiving coils as a function of its angular position relative to the stator element, and an evaluation circuit for determining the angular position of the rotor element relative to the stator element from voltage signals induced in the receiving coils.
An embodiment of a position sensor shown in
FIG. 3
of European patent application (0 159 191 A2) discloses such an angle sensor. A structural principle of this position, or angle, sensor is that secondary coils formed as angularly-periodic, interspaced, series-connected coil sequences are provided, with each coil sequence being formed of one or more pairs of coils connected in reversed polarity. Because of this reversed polarity connection, an output signal coupled in from primary coils to a coil sequence of secondary coils is respectively (approximately) zero.
A movable element, the position of which is to be determined relative to this coil arrangement, has a “flow coupler” that is structured to be small in contrast to dimensions of a measuring path and modifies coupling between the primary coil(s) and individual secondary coils. A coil sequence of secondary coils that contains a secondary coil influenced in this manner generates an output signal that is different from zero. Each of the coil sequences of secondary coils is connected with part of a phase shifting network so that, at an output of this network, an output signal dependent on the position of the movable element is phase shifted relative to the signal fed into the primary coil (s). An evaluation of a time difference between the signal fed into the primary coils and the output signal of the phase shifting network is used for determining a respective position of the movable element. In European patent document (EPA 0 159 191 A2), a magnetic element that is small relative to the measuring path or even a conducting ring (page 4, paragraph 2) is suggested as a flow coupler; the ring is characterized as disadvantageous since it produces only a weak output signal.
Use of a phase shifting network, whose tolerances significantly reduce a measuring accuracy of the sensor, is disadvantageous in this angle sensor. The zero output signal expected from the coil sequences of uninfluenced secondary coils is hardly achievable, at least not without additional costly balancing measures.
Therefore, it is an object of this invention to provide an angle sensor according to the introductory paragraph above whose structure is uncomplicated and inexpensive and which achieves a high degree of measuring accuracy without expensive balancing measures. Specifically, an inductive angle sensor according to this invention should be as insensitive to manufacturing and mounting tolerances as possible, as well as to environmental influences, particularly outside temperature.
SUMMARY
According to principles of this invention a rotor element of an inductive angle sensor of the introductory paragraph above forms at least one closed-loop lead that, at least over a partial area, forms a periodic repeating bend structure.
REFERENCES:
patent: Re. 32857 (1989-02-01), Luneau
patent: 4816759 (1989-03-01), Ames et al.
patent: 5077635 (1991-12-01), Bollhagen et al.
patent: 5406155 (1995-04-01), Persson
patent: 5594434 (1997-01-01), McCullough
patent: 5903205 (1999-05-01), Goto et al.
patent: 6011389 (2000-01-01), Masreliez et al.
patent: OS 21 48 703 (1973-04-01), None
patent: OS 2 158 713 (1973-06-01), None
patent: 33 28 421 A1 (1984-02-01), None
patent: 36 42 607 A1 (1988-06-01), None
patent: 36 42 678 A1 (1988-06-01), None
patent: 39 19 749 C2 (1991-01-01), None
patent: 43 35 701 C2 (1995-04-01), None
patent: 195 04 307 A1 (1996-08-01), None
patent: 0 159 191 (1985-10-01), None
Irle Henning
Kost Norbert
Schmidt Franz-Josef
Andersen Henry S.
Birch & Stewart Kolasch & Birch, LLP
Hella KG & Hueck Co.
Oda Christine K.
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