Induction detecting type rotary encoder
An induction detecting type rotary encoder includes: a stator; a rotor configured to be rotated with respect to a rotary shaft; a first transmitting coil; a second transmitting coil; a first receiving coil; a second receiving coil; a first magnetic flux coupling body; and a second magnetic flux coupling body. The first transmitting coil is disposed between the first and second receiving coils. A distance between the second transmitting coil and the rotary shaft is larger than that of the second receiving coil and the rotary shaft. The first magnetic flux coupling body forms a first track for causing a periodic change for each rotation. The second magnetic flux coupling body forms a second track for causing a periodic change for each rotation. The second magnetic flux coupling body has a pattern of which an inner peripheral side is substantially continuous in a circumferential direction.
1. An induction detecting type rotary encoder comprising:
a stator;
a rotor configured to be rotated with respect to a rotary shaft, the rotor being disposed while facing the stator;
a first transmitting coil disposed on a first surface of the stator, the first surface facing the rotor;
a second transmitting coil disposed on the first surface to surround the first transmitting coil, the second transmitting coil being arranged in a concentric pattern with the first transmitting coil with respect to the rotary shaft;
a first receiving coil disposed on the first surface;
a second receiving coil disposed on the first surface to surround the first receiving coil, the second receiving coil being arranged in a concentric pattern with the first receiving coil with respect to the rotary shaft;
a first magnetic flux coupling body disposed on a second surface of the rotor, the second surface facing the stator, the first magnetic flux coupling body magnetically coupling with the first receiving coil; and
a second magnetic flux coupling body disposed on the second surface to surround the first magnetic flux coupling body, the second magnetic flux coupling body being arranged in a concentric pattern with the first magnetic flux coupling body with respect to the rotary shaft, the second magnetic flux coupling body magnetically coupling with the second receiving coil, wherein:
the first transmitting coil is disposed between the first receiving coil and the second receiving coil;
a distance between the second transmitting coil and the rotary shaft is larger than a distance between the second receiving coil and the rotary shaft;
the first magnetic flux coupling body forms a first track for causing a periodic change for each rotation;
the second magnetic flux coupling body forms a second track for causing a periodic change for each rotation;
the second magnetic flux coupling body has a pattern of which an inner peripheral side is substantially continuous in a circumferential direction,
the second magnetic flux coupling body includes a first wiring and a second wiring, and
a magnetic flux coupling degree between the second transmitting coil and the first wiring of the second magnetic flux coupling body becomes larger than a magnetic flux coupling degree between the second transmitting coil and the second wiring of the second magnetic flux coupling body.
2. The induction detecting type rotary encoder according to claim 1 , wherein
the second magnetic flux coupling body includes:
the first wiring including a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
the second wiring which connects an inner peripheral side of the first wiring.
3. The induction detecting type rotary encoder according to claim 1 , wherein
the second magnetic flux coupling body includes:
the first wiring including a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
the second wiring including a second circular wiring which is located on an inner peripheral side of the first wiring.
4. The induction detecting type rotary encoder according to claim 1 , wherein
the second magnetic flux coupling body includes:
the first wiring including a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
the second wiring including a second close-loop-shaped wiring which is disposed to be fitted to the concave portions.
5. An induction detecting type rotary encoder comprising:
a stator;
a rotor configured to be rotated with respect to a rotary shaft, the rotor being disposed while facing the stator;
a first transmitting coil disposed on a first surface of the stator, the first surface facing the rotor;
a second transmitting coil disposed on the first surface to surround the first transmitting coil, the second transmitting coil being arranged in a concentric pattern with the first transmitting coil with respect to the rotary shaft;
a first receiving coil disposed on the first surface;
a second receiving coil disposed on the first surface to surround the first receiving coil, the second receiving coil being arranged in a concentric pattern with the first receiving coil with respect to the rotary shaft;
a first magnetic flux coupling body disposed on a second surface of the rotor, the second surface facing the stator, the first magnetic flux coupling body magnetically coupling with the first receiving coil; and
a second magnetic flux coupling body disposed on the second surface to surround the first magnetic flux coupling body, the second magnetic flux coupling body being arranged in a concentric pattern with the first magnetic flux coupling body with respect to the rotary shaft, the second magnetic flux coupling body magnetically coupling with the second receiving coil, wherein:
a distance between the first receiving coil and the rotary shaft is larger than a distance between the first transmitting coil and the rotary shaft;
the second transmitting coil is disposed between the first receiving coil and the second receiving coil;
the first magnetic flux coupling body forms a first track for causing a periodic change for each rotation;
the second magnetic flux coupling body forms a second track for causing a periodic change for each rotation;
the first magnetic flux coupling body has a pattern of which an outer peripheral side is substantially continuous in a circumferential direction,
the second magnetic flux coupling body includes a first wiring and a second wiring, and
a magnetic flux coupling degree between the second transmitting coil and the first wiring of the second magnetic flux coupling body becomes larger than a magnetic flux coupling degree between the second transmitting coil and the second wiring of the second magnetic flux coupling body.
6. The induction detecting type rotary encoder according to claim 5 , wherein
the first magnetic flux coupling body includes:
a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
a second wiring which connects an outer peripheral side of the first gear-shaped wiring.
7. The induction detecting type rotary encoder according to claim 5 , wherein
the first magnetic flux coupling body includes:
a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
a second circular wiring which is located on an outer peripheral side of the first gear-shaped wiring.
8. The induction detecting type rotary encoder according to claim 5 , wherein
the second magnetic flux coupling body includes:
the first wiring including a first gear-shaped wiring in which concave portions and convex portions are alternately formed in a circumferential direction; and
the second wiring including a second close-loop-shaped wiring which is disposed to be fitted to the concave portions.