JPH0448142Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to the structure of a rotor of an inductor resolver in which an excitation winding and a detection winding are wound around a stator, and the rotor is made of a salient pole body.

[Background technology of the invention]

A front view in cross section of a conventional example (non-vernier type) of this type of device is shown in FIG.

FIG. 2 is an explanatory diagram of the winding directions of the excitation (α phase, β phase) winding and the detection (θ phase) winding.

This resolver consists of a stator 1 that is made of laminated magnetic plates and has 16 salient poles (8 poles) formed on its inner periphery; a rotor 2 made of laminated magnetic plates with salient poles at intervals; a rotating shaft 3 to which the rotor 2 is fitted and fixed and rotated by another rotation drive source (not shown);
An α-phase excitation winding 4 that excites the stator 1, a β-phase excitation winding 5 through which an excitation current whose phase is shifted by π/2 in electrical angle from the α-phase flows, and a θ-phase that detects the rotational phase of the rotor 2. A detection winding 6 is provided.

In FIG. 2, the positive winding direction of the α-phase excitation winding 4 is represented by S and the opposite direction, the positive winding direction of the β-phase excitation winding 5 is represented by C and the opposite direction, and the θ-phase detection winding 6 The direction of flow at each salient pole of the stator is indicated by an arrow.

Considering this resolver as two poles, the equivalent circuit when an excitation current is passed through it to rotate the rotary shaft is shown in FIG.

Here, 7 is the direction of the rotating magnetic field due to the exciting current, 8 is the rotor rotation direction, AT ₁ to AT ₄ are the first to fourth distributed magnetomotive forces (ampere turns) in the stator, and Φ ₁ to Φ ₄ are AT ₁ ~The magnetic flux generated by AT ₄ , λ ₁ ~ _{λ 2} is the magnetic permeability (permeance) to the rotor of Φ ₁ ~ _{Φ 4} , N is the magnetic potential at the neutral point, and AT is the excitation The current (amplitude) is the number of amperes, ω is 2πf, f is the excitation frequency, λ ₀ is the average level of permeance, λ _n is the maximum positive or negative amplitude of permeance amplitude, (when permeance changes sinusoidally, λ The relationship between ₀ and λ _n is shown in Figure 5.) θ is the rotational mechanical angle of the rotating shaft, V〓 is the induced voltage of the θ phase detection winding, and n is the number of turns of the θ phase detection winding.

The relationship between the α-phase excitation current i and the β-phase excitation current i is shown in FIG.

Therefore, the circuit equation is AT ₁ −Φ ₁ /λ ₁ =N AT ₂ −Φ ₂ /λ ₂ =N AT ₃ −Φ ₃ /λ ₃ =N AT ₄ −Φ ₄ /λ ₄ =N...(1 ) Φ ₁ +Φ ₂ +Φ ₃ +Φ ₄ = 0 ...(2) where AT ₁ = AT・sinωt AT ₂ = −AT・cosωt AT ₃ = −AT・sinωt AT ₄ = AT・cosωt ...(3) Assuming that the permeance λ changes in a sinusoidal manner, λ ₁ = λ ₀ + λ _n・cosθ λ ₂ = λ ₀ −λ _n・sinθ λ ₃ = λ ₀ −λ _n・cosθ λ ₄ =λ ₀ +λ _n・sinθ ...(4). Therefore, N=λ ₁・AT ₁ +λ ₂・AT ₂ +λ ₃・AT ₃ +λ ₄・AT ₄ /λ ₁
+λ ₂ +λ ₃ +λ ₄ =λ _n・AT/2λ ₀ (sinωt・cosθ+cosωt・sinθ
)=λ _n /2λ ₀・AT・sin(ωt+θ)……(5) Each magnetic flux is: Φ ₁ = λ ₁ (AT ₁ −N) Φ ₂ = λ ₂ (AT ₂ −N) Φ ₃ = λ ₃ (AT ₃ -N) Φ ₄ = λ ₄ (AT ₄ -N) ...(6) The induced voltage V of the detection coil 6 is V = -n (dΦ ₁ /dt-dΦ ₂ /dt+dΦ ₃ /dt −dΦ ₄ /d
t) = -nd/dt (Φ ₁ -Φ ₂ +Φ ₃ -Φ ₄ ) = -nd/dt {λ ₁・AT ₁ −λ ₁・N−λ ₂・AT ₂ +λ ₂
・N+λ ₃・AT ₃ −λ ₃・N−λ ₄・AT ₄・λ ₄・N}
...(7) Here, d/dt is the time differential, and the inside of { } on the right side of equation (7) is { }=(λ ₁ − λ ₃ )・AT ₁ − (λ ₂ − λ ₄ )・AT ₂ −(
λ ₁ −λ ₂ +λ ₃ −λ ₄ )N =2λ _n・cosθ・sinωt−2λ _n sinθ・cosωt =2λ _n・sin(ωt−θ) ……(8) Therefore, V〓=−nd/ dt{2λ _n・sin(ωt−θ)}=−2n・
λ _n・ω・cos(ωt−θ)……(9).

This relationship is shown in FIGS. 6 and 7.

Therefore, the induced voltage V〓 becomes a so-called resolver whose phase changes in proportion to the mechanical angle θ'.

I'm thinking of two poles now. θ=θ′……(10) becomes.

[Problems with background technology]

By the way, the rotor of the conventional example has the shape of the seventh
(perspective view), the permeance λ changes with its rotation in a rectangular shape as shown in Figure 8a, which consists of the fundamental wave of b, the 3rd harmonic of c, and the 5th harmonic of d.
It is a superposition of harmonics, etc.

That is, when k ₁ , k ₃ , k ₅ , . . . are constants, equation (4) can be expressed as follows.

λ ₁ = λ ₀ + λ _n (k ₁ cos θ + k ₃ cos 3 θ + k ₅ cos 5 θ) λ ₂ = λ ₀ + λ _n {k ₁ cos (θ + π/2) + k ₃ cos 3 (θ +
π/2) + k ₅ cos5 (θ + π/2)} λ ₃ = λ ₀ + λ _n {k ₁ cos (θ + π) + k ₃ cos3 (θ + π)
+k ₅ cos5(θ+π)} λ ₄ =λ ₀ +λ _n {k ₃ cos(θ+3/2π)+k ₃ cos3(θ
+3/2π)+k ₅ cos5(θ+3/2π)}……(11) Here, in equation (8), λ ₁ −λ ₃ =λ _n [k ₁ {cosθ−cos(θ+π)}+k ₃ {c
os3θ−cos3(θ+π)}+k ₅ {cos5θ−cos5(θ+π
)}] =λ _n [2k ₁ cosθ+2k ₃ cos3θ+2k ₅ cos5θ] …(12) λ ₂ −λ ₄ =λ _n [k ₁ {cos(θ+π/2)−cos(θ+
3/2π)} +K ₃ {cos3(θ+π/2)−cos3(θ+3/2π)
}+k ₅ {cos5(θ+π/2)−cos5(θ+3/2π)}
] =λ _n [−2k ₁ sinθ+2k ₃ sin3θ−2k ₅ sin5θ]……(
13) Also, λ ₁ −λ ₂ +λ ₃ −λ ₄ =0 (14). Therefore, from equations (7), (8), (12), and (13),
The induced voltage V〓 of the detection coil 6 is V〓=-nd/dt {(λ ₁ − λ ₃ )・AT ₁ −(λ ₂ − λ ₄ )
・AT ₂ }=-nd/dt [2λ _n {k ₁ cosθ+k ₃ cos3θ+k ₅ cos5θ}AT・sinω
t＋2λ _n {−k ₁ sinθ＋k ₃ sinθ −k ₅ sin5θ}cosωt〕＝−2ωnλ _n・AT〔{k ₁ cosθ
＋k ₃ cos3θ＋k ₅ cos5θ｝cosωt +{−k ₁ sinθ＋k ₃ sin3θ−k ₅ sin5θ}(−sinωt
)〕=−2ωnλ _n・AT〔k ₁ cos(ωt−θ)＋k ₃ cos(ωt＋3θ)＋k ₅ cos
(ωt−5θ)]...(15)

From equation (9), the induced voltage V〓 of an ideal resolver is: V〓=−2ωnλ _n・AT・k ₁ cos (ωt−θ)
...(9'), and from equations (15) and (9'), in the conventional example, the permeance waveform includes harmonics [Fig. 9 c, d] in addition to the fundamental wave [Fig. 9 b], A phase error occurs in the induced voltage V to the θ phase detection winding 6, which is a problem.

[Purpose of invention]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of conventional devices and to provide an inductor type resolver having a rotor structure in which no phase error occurs.

[Summary of the idea]

In this invention, in order to obtain a resolver with characteristics with little phase error, the change in permeance must be sinusoidal, and the permeance ∝ area of rotor salient pole surface/gap length between stator and rotor. This is an inductor type resolver in which a sinusoidal approximation skew is formed in the axial direction on the salient poles of the rotor.

[Example of idea]

FIG. 10 shows a perspective view of an embodiment of the present invention.

This rotor 2 corresponds to the eight-pole inductor resolver shown in FIG. 1, and the axial shape of all the protrusions of the rotor 2 forms a skew 7 that approximates a sine wave.

Molding into such a shape can be easily performed using a machining center or the like.

In this invention, permeance ∝ area of rotor salient pole surface/gap length between stator and rotor, and in order to obtain a resolver with characteristics with little phase error, permeance changes must be sinusoidal. It is based on In other words, making the change in permeance a sine wave is
It is based on the fact that the change in area of the salient pole surface roughly corresponds to a sine wave.

In this embodiment, FIG. 11 is a side view of the rotor, FIG. 12 is a front view of the rotor, and FIG. 13 is a developed view of the rotor surface.

The present invention has been described with reference to an example in which there are four rotor protrusions, but the number may be 1, 2, 3, 4, 5, 6,
Any number such as 7, 8, 9, . . . can be applied.

FIG. 14 shows that the change in permeance λ due to the rotation of the mechanical angle θ in this embodiment exhibits a sinusoidal shape.

[Effect of idea]

Thus, according to the present invention, there is a need for an inductor type resolver with a high level of accuracy with significantly less detection error, and a device with significantly improved reliability and ease of mass production has been obtained, and has become an industry leader in this field. There are great benefits to this.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the configuration of a conventional example, Fig. 2 is a distribution diagram of each winding, Fig. 3 is a magnetic equivalent circuit diagram, Fig. 4 is a relation diagram of excitation current (α phase, β phase), Figure 5 is a diagram of changes in magnetic permeability due to rotation of mechanical angle, Figure 6 is a diagram of changes in exciting current and detection voltage due to rotation, Figure 7 is a diagram of the relationship between rotational mechanical angle and detection phase, and Figure 8 is a diagram of changes in magnetic permeability due to rotation of mechanical angle. A perspective view of a conventional rotor, FIGS. 9a to 9d are analysis diagrams of changes in permeance due to rotation, FIG. 10 is a perspective view of a rotor in an embodiment of the present invention, and FIG. 11 is a side view thereof. , FIG. 12 is a front view thereof, FIG. 13 is a developed view thereof, and FIG. 14 is an explanatory diagram of changes in permeance due to rotation. 1... Stator, 2... Rotor, 3... Rotating shaft,
4...α-phase excitation winding, 5...β-phase excitation winding, 6...
...θ phase detection winding, 7...Sine wave skew.

Claims (1)

[Claims for Utility Model Registration] 1. On the rotation direction protrusion provided on the outer peripheral side of the rotor,
An inductor type resolver characterized by forming a sinusoidal skew in the direction of the rotation axis. 2. A stator made of a magnetic material having a plurality of protrusions arranged at equal intervals on its inner periphery; an α-phase excitation winding wound around every other protrusion to allow an α-phase AC excitation current to flow therethrough; A β-phase excitation winding is wound around every other protruding portion to flow a β-phase AC excitation current electrically shifted by π/2 from the α phase, and a β-phase excitation winding is wound around every other protruding portion to conduct θ-phase detection. a θ-phase detection winding in which a voltage is induced; a rotor made of a magnetic material that faces the stator through a gap, is fitted and fixed to a rotating shaft, and has the protrusions arranged at equal intervals on its outer periphery, and is rotatable; An inductor type resolver according to claim 1, comprising: a rotating shaft supported by a rotating shaft; and a rotating shaft supported by a rotating shaft.