Resolver
A resolver includes a sine coil and a cosine coil that transmit AC signals having phases of the electrical angle different from each other by 90 degrees in one of a sheet-like excitation coil and a sheet-like detection coil disposed at a rotor or a stator, and a counter coil or a conductor disposed to face the sine coil and the cosine coil in the other of the excitation coil and the detection coil. In addition, an area (S) of a portion where each of the sine coil and the cosine coil and the counter coil or the conductor overlap each other when viewed in the axial direction of the resolver changes into a sinusoidal shape as the rotor rotates.
1. A resolver that detects a rotation angle of a rotor with respect to a stator, the resolver comprising:
a sine coil and a cosine coil that transmit AC signals in which phases of an electrical angle are different from each other by 90 degrees in one of a sheet-like excitation coil and a sheet-like detection coil disposed at the rotor or the stator; and
a counter coil or a conductor disposed to face the sine coil and the cosine coil in the other of the excitation coil and the detection coil, wherein
an area of a portion where each of the sine coil and the cosine coil overlap the counter coil or the conductor when viewed in an axial direction of the resolver changes into a sinusoidal shape as the rotor rotates,
each of the sine coil and the cosine coil has a shape that changes a radial width into a sinusoidal shape with respect to a deflection angle in a polar coordinate plane with a rotation axis of the rotor as a reference,
each of the sine coil and the cosine coil has a first coil for generating one of a magnetic pole pair and a second coil for generating the other of the magnetic pole pair,
the first coil and the second coil are disposed on an identical plane so as not to overlap each other, and
the first coil and the second coil are disposed so as to be adjacent to each other without a gap in a radial direction.
2. The resolver according to claim 1 , wherein
the counter coil is formed in an annular shape coaxial with a rotation axis of the rotor.
3. The resolver according to claim 1 , wherein
the excitation coil and the detection coil are both provided at the stator, and
the rotor includes a conductor that generates a diamagnetic field in a direction of canceling a magnetic field of the excitation coil with a magnitude according to the rotation angle.
4. The resolver according to claim 1 , wherein
the excitation coil and the detection coil are disposed to face the rotor and the stator.
5. The resolver according to claim 1 , wherein
each of the first coil and the second coil is formed in a circular pattern, and
when a clockwise current flows in the first coil, a counterclockwise current flows in the second coil.
6. A resolver that detects a rotation angle of a rotor with respect to a stator, the resolver comprising:
a sine coil and a cosine coil that transmit AC signals in which phases of an electrical angle are different from each other by 90 degrees in one of a sheet-like excitation coil and a sheet-like detection coil disposed at the rotor or the stator; and
a counter coil or a conductor disposed to face the sine coil and the cosine coil in the other of the excitation coil and the detection coil, wherein
an area of a portion where each of the sine coil and the cosine coil overlap the counter coil or the conductor when viewed in an axial direction of the resolver changes into a sinusoidal shape as the rotor rotates,
each of the sine coil and the cosine coil has a shape that changes a radial width into a sinusoidal shape with respect to a deflection angle in a polar coordinate plane with a rotation axis of the rotor as a reference, and
each of the sine coil and the cosine coil is formed in a shape corresponding to a region surrounded by a curve expressed by Expressions 1 and 2 in a polar coordinate plane with a rotation axis of the rotor as a reference
[
Math
1
]
r
=
(
R
1
-
R
2
)
{
cos
(
θ
-
3
4
π
)
+
1
2
}
+
R
2
,
0
≤
θ
≤
π
Expression
1
r
=
(
R
1
-
R
2
)
{
sin
(
θ
-
3
4
π
)
+
1
2
}
+
R
2
,
0
≤
θ
≤
π
Expression
2
R 1 : Outer diameter, R 2 : Inner diameter, r: Distance from origin, θ: Deflection angle.