Rotational angle detecting apparatus and torque detecting apparatus

A rotational angle detecting apparatus comprising:

• a plurality of detectors, disposed respectively to face a target made of a magnetic material and provided on a rotating member, for detecting the target and outputting detection signals having phases according to the position of the target which changes with a rotation of the rotating member;
• and
• a controller capable of performing operations of
• executing a predetermined operation on the detection signals respectively outputted from the detectors;
• storing ones of a plurality of tables and a plurality of conversion formulas, said tables representing the correlation of each operation result obtained by executing the predetermined operation in advance for different gaps between the target and the detectors with a corresponding electrical angle of the detection signals, said conversion formulas representing the relationship between the operation result and the electrical angle of the detection signals for different gaps between the target and the detectors;
• determining the gap based on the detection signals respectively outputted from the detectors;
• converting the result of the executed operation into the electrical angle of the detection signals based on one of the table and the conversion formula corresponding to the determined gap;
• and
• detecting a rotational angle of the rotating member based on the obtained electrical angle.

A method of detecting a rotation angle of a rotating member supporting a magnetic target comprising the steps of:

• providing first and second detectors facing the target and spaced from the target by a gap;
• detecting the target and outputting first and second detection signals having phases related to the relative positions of the first and second detectors and the target;
• performing a predetermined operation on the first and second detection signals and obtaining a given operation result;
• providing either:
• a first table including, for a first gap, correlations between operation results obtained in advance for various positions of the target and electrical angles of the detection signals, and a second table including, for a second gap, correlations between operation results obtained in advance for various positions of the target and electrical angles of the detection signals;
• or
• first and second conversion formulas representing the relationship between operation results obtained in advance for various positions of the target and the electrical angle of the detection signals for first and second gaps;
• converting the given operation result into an electrical angle based on the first and second tables or the first and second of conversion formulas;
• and
• determining a rotational angle of the rotating member based on the obtained electrical angle.

A rotational angle detecting apparatus comprising:

• first and second detectors disposed adjacent a magnetic target on a rotating member, said first and second detectors outputting first and second detection signals having phases related to the position of the target with respect to the first and second detectors;
• an operating circuit for performing a predetermined operation on the first and second detection signals and producing an operation result;
• a converting circuit for converting the operation result into an electrical angle based on a first table including, for a first gap, correlations between operation results obtained in advance for various positions of the target and electrical angles of the detection signals, and a second table including, for a second gap, correlations between operation results obtained in advance for various positions of the target and electrical angles of the detection signals or based on first and second conversion formulas representing the relationship between operation results obtained in advance for various positions of the target and the electrical angle of the detection signals for first and second gaps;
• and
• a determining circuit for determining a gap between the target and the first and second detectors based on the detection signals outputted from the first and second detectors, wherein
• the converting circuit converts an operation result into an electrical angle based on the first and second tables or the first and second conversion formulas and determines a rotational angle of the rotating member based on the obtained electrical angle.