Rotation angle detecting device
OwnerHiroomi Ogasawara, Masaomi Ogasawarainventors
Life of this patent
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Abstract
A rotation angle detecting device with a pair of variable capacitors which are formed with a rotating object, i.e. a movable electrode, and two stationary electrodes disposed around the rotating object, so that the capacitors operate in a differential mode. Alternatively, the central electrode can be stationary while the two outer electrodes move with the rotating object. The capacitors are combined with oscillators, so that a signal varying with the rotation of the rotating object is provided by obtaining the difference between the output frequencies of the oscillators.
Claims10
A device for measuring the amount of rotation of a rotatable object comprising:
- (a) sensor means including a first electrode plate;
- a pair of second electrode plates confronting said first electrode plate and spaced therefrom by a first distance and a second distance respectively to form therewith a pair of capacitors;
- and means responsive to rotation of the rotatable object for producing relative rotation between (i) said first electrode plate and (ii) said pair of second electrode plates in an eccentric manner to vary the first distance and the second distance differentially so that as the rotatable object rotates the capacitance of one of the capacitors increases while the capacitance of the other of the capacitors correspondingly decreases differentially;
- (b) two oscillator circuits, each having an associated one of the capacitors incorporated therein as a frequency varying component;
- and
- (c) mixer means connected to said two oscillator circuits for providing a frequency difference signal determined by the difference in the frequencies of said two oscillator circuits and indicative of the extent of rotation of the rotatable object.
Dependencies are inferred from the claim text.