Rotation angle detector

A rotation angle detector for detecting a rotation angle of a detectable rotation body, comprising:

• a primary rotation body to be attached to the detectable rotation body and to rotate as integral with the detectable rotation body;
• a secondary rotation body to rotate as a predetermined rotation ratio for the primary rotation body;
• a primary rotation detection mechanism to output a signal to be varied periodically as corresponding to a rotation of the primary rotation body;
• a secondary rotation detection mechanism to output a signal to be varied periodically as corresponding to a rotation of the secondary rotation body;
• a signal processing unit to convert a cycle of the signals that the primary rotation detection mechanism and the secondary rotation detection mechanism output, and to calculate the rotation angles of the primary rotation body and the secondary rotation body regarding the converted cycle by using the signals;
• and
• an operation processing unit to calculate the rotation angle of the detectable rotation body, based on the calculated rotation angle of the primary rotation body or of the secondary rotation body, on a relative rotation angle between the primary rotation body and the secondary rotation body, and on the converted cycle.

A rotation angle detector for detecting a rotation angle of a detectable rotation body, comprising:

• a primary rotation body to be attached to the detectable rotation body and to rotate as integral with the detectable rotation body;
• a secondary rotation body to rotate as a predetermined rotation ratio for the primary rotation body;
• a primary rotation detection mechanism to output a continuous signal to be varied periodically as corresponding to a rotation of the primary rotation body;
• a secondary rotation detection mechanism to output a continuous signal to be varied periodically as corresponding to a rotation of the secondary rotation body;
• a signal processing unit to calculate the rotation angles of the primary rotation body and the secondary rotation body using the signals that the primary rotation detection mechanism and the secondary rotation detection mechanism output;
• and
• an operation processing unit to calculate the rotation angle of the detectable rotation body, based on the calculated rotation angle of the primary rotation body or of the secondary rotation body, on a relative rotation angle between the primary rotation body and the secondary rotation body, and on cycles of the signals that the primary rotation detection mechanism and the secondary rotation detection mechanism output.

A rotation angle detector for detecting a rotation angle of a detectable rotation body, comprising:

• a primary rotation body to be attached to the detectable rotation body and to rotate as integral with the detectable rotation body;
• a secondary rotation body to rotate as a predetermined rotation ratio for the primary rotation body;
• a primary rotation detection mechanism to output a continuous signal to be varied periodically as corresponding to a rotation of the primary rotation body, with a periodicity of n as an integer of not less than two for one rotation of the primary rotation body;
• a secondary rotation detection mechanism to output a continuous signal to be varied periodically as corresponding to a rotation of the secondary rotation body, with a periodicity of m as an integer of less than n but not less than one for one rotation of the secondary rotation body;
• a signal processing unit to calculate the rotation angles of the primary rotation body and the secondary rotation body using the signals that the primary rotation detection mechanism and the secondary rotation detection mechanism output;
• and
• an operation processing unit to calculate the rotation angle of the detectable rotation body, based on the calculated rotation angle of the primary rotation body or of the secondary rotation body, on a relative rotation angle between the primary rotation body and the secondary rotation body, and on cycles of the signals that the primary rotation detection mechanism and the secondary rotation detection mechanism output.