Capacity type rotation detecting apparatus
First Claim
1. A capacity type rotation detecting apparatus comprising:
- a first plate having a plurality of electrode pieces of a first input electrode and a plurality of electrode pieces of a second input electrode arranged along a circumference at respective equally given intervals and contiguously intermeshed, said first input electrode pieces forming a first input reference angular position detection electrode comprising a set of said first input electrode pieces selected at respective different intervals and further forming a first input rotational angle detection electrode comprising a set of said first input electrode pieces other than said first input reference angular position detection electrode pieces, and said second input electrode pieces forming a second input reference angular position detection electrode comprising a set of said second input electrode pieces each thereof being positioned adjacent to one of said first input reference angular position detection electrode pieces on one side thereof and further forming a second input rotational angle detection electrode comprising a set of said second input electrode pieces other than said second input reference angular position detection electrode pieces,a second plate having output reference angular position detection electrode means arranged to face said first and second input reference angular position detection electrodes and output rotational angle detection electrode means arranged to face said first and second input rotational angle detection electrodes;
a first periodic signal supply circuit for supplying periodic signals of opposite phase to said first and second input reference angular position detection electrodes;
a second periodic signal supply circuit for supplying periodic signals, which are of opposite phase to each other and have a repetition period different from that of said periodic signals supplied to said first and second input reference angular position detection electrodes, to said first and second input rotational angle detection electrodes;
a reference angular position signal generating circuit for generating a reference angular position signal in response to signals generated at said output reference angular position detection electrode means when said second plate is rotated relative to said first plate;
a rotational angle signal generating circuit for generating a rotational angle signal in response to signals generated at said output rotational angle detection electrode means; and
signal transmitting means for transmitting signals between said second plate and said first plate which is fixed.
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Accused Products
Abstract
A capacity type rotation detecting apparatus includes a fixed first plate and a rotational second plate which are arranged to face each other and are respectively made of an electrically insulating material. Provided on the first plate are a plurality of electrodes arranged circumferentially and forming a pair of sets of input rotational angle detection electrodes and a pair of sets of input reference angular position detection electrodes and at least two capacitive coupling signal transmitting electrically conductive rings. Also provided on the second plate are at least one set of output rotational angle detection electrodes and at least one set of output reference angular position detection electrodes arranged to face the respective pairs of sets of electrodes on the first plate and at least two capacitive coupling signal transmitting electrically conductive rings which are respectively connected to the at least two sets of electrodes on the second plate and respectively arranged to face the at least two rings on the first plate. The capacity type rotation detecting apparatus further includes first and second periodic signal supply circuits which have different repetition periods and respectively supply detecting signals of opposite phase to the respective pairs of sets of input electrodes on the first plate, and a rotational angle signal generating circuit and a reference angular position signal generating circuit responsive to respective signals generated at the at least two rings on the first plate to generate a rotational angle detection signal and a reference angular position detection signal, respectively, thereby simultaneously providing detection signals accurately without any delay irrespective of the rotational speeds of the second plate.
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Citations
7 Claims
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1. A capacity type rotation detecting apparatus comprising:
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a first plate having a plurality of electrode pieces of a first input electrode and a plurality of electrode pieces of a second input electrode arranged along a circumference at respective equally given intervals and contiguously intermeshed, said first input electrode pieces forming a first input reference angular position detection electrode comprising a set of said first input electrode pieces selected at respective different intervals and further forming a first input rotational angle detection electrode comprising a set of said first input electrode pieces other than said first input reference angular position detection electrode pieces, and said second input electrode pieces forming a second input reference angular position detection electrode comprising a set of said second input electrode pieces each thereof being positioned adjacent to one of said first input reference angular position detection electrode pieces on one side thereof and further forming a second input rotational angle detection electrode comprising a set of said second input electrode pieces other than said second input reference angular position detection electrode pieces, a second plate having output reference angular position detection electrode means arranged to face said first and second input reference angular position detection electrodes and output rotational angle detection electrode means arranged to face said first and second input rotational angle detection electrodes; a first periodic signal supply circuit for supplying periodic signals of opposite phase to said first and second input reference angular position detection electrodes; a second periodic signal supply circuit for supplying periodic signals, which are of opposite phase to each other and have a repetition period different from that of said periodic signals supplied to said first and second input reference angular position detection electrodes, to said first and second input rotational angle detection electrodes; a reference angular position signal generating circuit for generating a reference angular position signal in response to signals generated at said output reference angular position detection electrode means when said second plate is rotated relative to said first plate; a rotational angle signal generating circuit for generating a rotational angle signal in response to signals generated at said output rotational angle detection electrode means; and signal transmitting means for transmitting signals between said second plate and said first plate which is fixed. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification