Electrical centering and boring system for transducers

A method of locating the center of an angular position transducer element for subsequent boring, comprising the steps of:

• placing a blank transducer element to be bored in an operative relationship with a master transducer element;
• rotating one of the transducer elements with respect to the other at a constant speed about an axis of relative rotation, the master element being deliberately eccentric with respect to the axis of relative rotation;
• energizing one of the transducer elements and thereby inducing a corresponding signal in the other;
• processing the induced signal to derive therefrom an error signal indicative of the eccentricity of the blank element with respect to the axis of relative rotation;
• resolving the error signal into orthogonally related components;
• and
• moving the blank element in a plane perpendicular to the axis of relative rotation until the resolved components of the error signal are both zero and the blank element is therefore concentric with the axis of relative rotation.

A method of boring an accurate center-hole in an angular position transducer element, comprising the steps of:

• rotating a master rotor element at a constant speed about an axis of rotation having significant eccentricity with respect to the center of the rotor element;
• holding a blank stator element to be bored in an operative relationship with the rotor element;
• energizing the stator element with a radio-frequency signal, and thereby inducing a corresponding signal in the rotor element;
• demodulating the signal induced in the rotor element, to obtain an intermediate signal having a position-related component with amplitude variations due to incremental changes in angular position of the rotor, and having an eccentricity error signal component with an amplitude cycle corresponding to each revolution of the rotor;
• rectifying and filtering the intermediate signal to obtain therefrom the eccentricity error signal component;
• resolving the eccentricity error signal component into x and y components by sampling the error signal component at points spaced by ninety-degree intervals and corresponding to times of transition of the center of the rotor element through x and y axes;
• displaying the x and y components of the eccentricity error signal;
• moving the blank stator element along the x and y axes until the x and y error components are reduced to zero;
• and
• boring the blank stator element utilizing means rotatable about the axis or rotation of the rotor element.

Apparatus for electrically locating the center of an angular position transducer element for subsequent boring, said apparatus comprising:

• means for holding a blank transducer element to be bored and a master transducer element in an operative relationship with each other;
• means for rotating one of the transducer elements with respect to the other at a constant speed about an axis of relative rotation, the master transducer element being deliberately eccentric with respect to the axis of rotation;
• signal generation means coupled with one of the transducer elements thereby to produce an induced signal in the other;
• signal processing means couple to receive the induced signal, for deriving therefrom an eccentricity error signal indicative of any eccentricity of the blank transducer element with respect to the axis of relative rotation;
• error signal resolution means for resolving the derived error signal into orthogonally related components;
• and
• means for moving the blank transducer element in orthogonally related axes perpendicular to the axis of relative rotation until the resolved components of the error signal are zero and the blank element is therefore concentric with the axis of relative rotation.

Apparatus for electrically locating the center of an angular position transducer element for subsequent boring, said apparatus comprising:

• means for holding a rotor transducer element with its center deliberately eccentric with respect to an axis of rotation;
• means for rotating the rotor element about the axis at a constant speed;
• stator holder means for holding a blank stator element, to be bored, in an operative relationship with the rotor element;
• signal generation means coupled with the stator element thereby to induce a signal in the rotor element;
• signal processing means coupled with the rotor element to receive the induced signal, for deriving therefrom an eccentricity error signal indicative of any eccentricity of the stator element with respect to the axis of rotation;
• error signal resolution means for resolving the derived error signal into orthogonally related components;
• and
• means for moving said stator holder means in orthogonally related axes perpendicular to the axis of rotation until the resolved components of the error signal are zero and the stator element is therefore concentric with the axis of rotation.

Apparatus for electrically locating and boring the center of an angular position transducer element, said apparatus comprising:

• means for holding a rotor transducer element with its center deliberately eccentric with respect to an axis of rotation;
• means for rotating the rotor element about the axis at a constant speed, including a drive motor and motor speed control means;
• stator holder means for holding a blank stator element in an operative relationship with the rotor element;
• signal generation means, including means for generating a relatively high-frequency carrier signal, said signal generation means being connectable with the stator element to induce a corresponding signal in the rotor element, the induced signal being amplitude-modulated by variations in electrical coupling between the rotor and stator elements caused by rotation of the rotor, whereby the induced signal includes a carrier-frequency component modulated by a position-indicating signal varying once per angular position increment and further modulated by an eccentricity error signal;
• signal processing means for receiving and processing the induced signal, including demodulation means for removing the carrier-frequency component, and rectifying and filtering means for isolating the eccentricity error signal;
• error signal resolution means for resolving the eccenticity error signal into orthogonally related components, said error signal resolution means including
• means for sampling the eccentricity error signal at preselected points in its cycle, by generating sampling pulses at times when the angular position of the center of the rotor element coincides with orthogonally related axes, and
• means for holding the sampled values of the eccentricity error signal;
• means for visibly displaying the sampled values of the eccentricity error signal;
• means for moving said stator holder means in the orthogonally related axes until the resolved components of the eccentricity error signal are zero and the stator element is therefore concentric with the axis of rotation of the rotor element;
• and
• boring means movable along and rotatable about the axis of rotor rotation, for accurately boring the stator element after location of its center.