1. A motor rotational angle detection device comprising:
a plurality of motor rotational angle detection units (6 and 7) configured to detect a
rotational angle of a motor (1); and
a normal angle decision device (8) configured to include a motor rotational angle
information item and to decide a normal motor rotational angle; wherein
the normal angle decision device (8) is characterized by being configured to, when a
difference is detected between output values of the plurality of motor rotational angle
detection units (6 and 7), respectively compare the output value of each of the motor
rotational angle detection units (6 and 7) with the motor rotational angle information item
included in the normal angle decision device (8), and to identify the motor rotational
angle detection unit (6) providing the smallest difference as the normal motor rotational
angle detection unit (6), and to decide the normal motor rotational angle.
2. The motor rotational angle detection device as claimed in claim 1, wherein the
plurality of motor rotational angle detection units are composed of a main rotation sensor
(6) and a sub-rotation sensor (7), and the motor rotational angle information item, which
is included in the normal angle decision device (8), is obtained from a redundant rotation
sensor (9), and the normal angle decision device (8) is configured to, when a difference,
which is greater than or equal to a predetermined value, is detected between the output
values of the main rotation sensor (6) and the sub-rotation sensor (7), compare each of the
output values of the main rotation sensor (6) and the sub-rotation sensor (7) with the
motor rotational angle information item, which is obtained from the redundant rotation
sensor (9), of the normal angle decision device (8), and to identify the motor rotational
angle detection unit (6) providing the smallest difference as the normal motor rotational
angle detection unit (6), and to decide the normal motor rotational angle.
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3. The motor rotational angle detection device as claimed in claim 1 or claim 2, wherein the normal angle decision device (8) is configured to, when a difference is detected between the output values of the plurality of motor rotational angle detection units (6 and 7), respectively compare the output value of each of the motor rotational angle detection units (6 and 7) with the motor rotational angle information item included in the normal angle decision device (8), and to identify the motor rotational angle detection unit (6) providing the smallest difference as the normal motor rotational angle detection unit (6), and to output the motor rotational angle information item, which is included in the normal angle decision device (8), as the motor rotational angle.
4. The motor rotational angle detection device as claimed in claim 1 or claim 2, wherein the normal angle decision device (8) is configured to, when a difference is detected between the output values of the plurality of motor rotational angle detection units (6 and 7), respectively compare the output value of each of the motor rotational angle detection units (6 and 7) with the motor rotational angle information item included in the normal angle decision device (8), and to identify the motor rotational angle detection unit (6) providing the smallest difference as the normal motor rotational angle detection unit (6), and to communicate to the outside an abnormality of the difference when the one motor rotational angle detection unit (6) is identified as a normal unit, and a difference is detected between the output value of the motor rotational angle detection unit (6), which is identified as the normal unit, and the motor rotational angle information item, which is included in the normal angle decision device (8).
5. The motor rotational angle detection device as claimed in claim 1, wherein the normal angle decision device (8) is configured to respectively compare the output value of each of the motor rotational angle detection units (6 and 7) with the motor rotational angle information item included in the normal angle decision device (8), when a difference between the motor rotational angle information item, which is included in the normal angle decision device (8), and the output value of the motor rotational angle detection unit (6) is greater than or equal to a predetermined value, and to inform the outside of an abnormality of the difference.
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6. The motor rotational angle detection device as claimed in claim 1, wherein the motor rotational angle detection units (6 and 7) are composed of magnetic detection elements, and are mounted on a board (17) which is faced to a magnet (20) attached to a shaft end of the motor (1) so as to be arranged, and configured to detect a magnet field variation of the magnet (20), and to obtain the rotational angle of the motor (1), and the motor rotational angle information item, which is included in the normal angle decision device (8), is the motor rotational angle information item which is computed and obtained by a microcomputer (3) of a control unit (2) for controlling the motor (1).
7. The motor rotational angle detection device as claimed in claim 2, wherein the main rotation sensor (6) and the sub-rotation sensor (7) of the motor rotational angle detection units, and the redundant rotation sensor (9), by which the normal angle decision device (8) is configured to obtain the motor rotational angle information item, are composed of magnetic detection elements, and are mounted on a board (17) which is faced to a magnet (20) attached to a shaft end of the motor (1) so as to be arranged, and configured to detect a magnet field variation of the magnet (20).
8. The motor rotational angle detection device as claimed in claim 7, wherein the two rotation sensors in the main rotation sensor (6), the sub-rotation sensor (7), and the redundant rotation sensor (9) are mounted on a surface of the board (17), and the remaining one rotation sensor is mounted on the other surface of the board (17), wherein the two rotation sensors, which are mounted on a surface of the board (17), are concurrently arranged at a position extended from a shaft of the motor (1).
9. The motor rotational angle detection device as claimed in claim 7, wherein the rotation sensor which is mounted on a surface, which is distant from the shaft end of the motor (1), of the board (17), is the redundant rotation sensor (9) by which the normal angle decision device (8) is configured to obtain the motor rotational angle information item.
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10. A motor rotational angle detection device comprising:
at least three motor rotational angle detection units
configured to detect a rotational angle of a motor (1); wherein
the motor rotational angle detection device is
characterized by being configured to identify, when a difference is detected between motor rotational angles which are outputted from the at least the three motor rotational angle detection units (6, 7, and 9), the two motor rotational angle detection units (7 and 9) providing the smallest difference in the motor rotational angles which are outputted from at least the three motor rotational angle detection units (6, 7, and 9), as the normal motor rotational angle detection units, and to inform the outside, when a difference is detected between the motor rotational angles, which are outputted from the two motor rotational angle detection units (7 and 9), in the two motor rotational angle detection units (7 and 9) which are identified as the normal motor rotational angle detection units, of an abnormality of the difference .
11. A motor rotational angle detection device comprising:
at least four motor rotational angle detection units configured to detect a rotational angle of a motor (1); wherein
the four motor rotational angle detection units (6, 7, 42, and 43) are formed as two pairs of motor rotational angle detection units, and wherein the motor rotational angle detection device is characterized by being configured to identify, when a difference is detected between motor rotational angles, which are outputted from the motor rotational angle detection units (6 and 7), in any pair of the two pairs of motor rotational angle detection units, the pair of motor rotational angle detection units (42 and 43), in which a difference is not detected, as the normal motor rotational angle detection units, and to inform to the outside, when a difference is detected between motor rotational angles, which are outputted from the pairs of motor rotational angle detection units (42 and 43), in the pair of motor rotational angle detection units (42 and 43) which are identified as the normal motor rotational angle detection units, of an abnormality of the difference is.
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12. The electric power steering device comprising the motor rotational angle detection device, which is claimed in any one of claim 1, claim 10, and claim 11, , wherein the motor (1) is configured to be used as a driving motor, and at least one of the motor rotational angle detection units is configured to continue a detection of a motor rotational angle when an ignition of a vehicle is turned off.
13. The electric power steering device comprising the motor rotational angle detection devices (6, 7, and 9), which are claimed in claim 2, wherein the motor (1) is configured to be used as a driving motor, and the redundant rotation sensor (9) is configured to be operated as a rotation sensor for obtaining the motor rotational angle information item, which is included in the normal angle decision device (8), when an ignition of a vehicle is turned on, and to continue a detection of a motor rotational angle when the ignition of the vehicle is turned off.
14. The electric power steering device comprising the motor rotational angle detection devices (6, 7, and 9), which are claimed in claim 7, wherein the motor (1) is configured to be used as a driving motor, and the main rotation sensor (6), the sub-rotation sensor (7), or the redundant rotation sensor (9) is mounted on a surface, which is distant from the shaft end of the motor (1), of the board (17), and is configured to continue a detection of a motor rotational angle when an ignition of a vehicle is turned off.
15. The electric power steering device as claimed in any one of claims 12 through 14, configured to calculate rudder angle information item by using a motor rotational angle which is obtained by continuing a detection of the motor rotational angle when an ignition of a vehicle is turned off.