JPH086262Y2 - Magnetic resolver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a magnetic leakage prevention measure for a magnetic resolver having a sin phase coil and a cos phase coil.

<Prior Art> Such a magnetic resolver has been disclosed in the application specification of Japanese Patent Application No. 1-284526 filed by the present applicant.

In this magnetic resolver, the number of stator plates is one, and as coils wound around salient poles of this stator plate, a coil excited by a sin phase voltage and a coil excited by a cos phase voltage are provided, and induction of these coils is provided. A phase modulation type rotation detection signal is obtained based on the voltage.

<Problems to be solved by the invention> However, the magnetic resolver having the sin phase coil and the cos phase coil has the following peculiar problems.

The magnetic flux of the sin phase coil and the magnetic flux of the cos phase coil interfere,
The amount of change in magnetic flux in the coil portion when the rotor of the magnetic resolver rotates becomes small. In addition, the leakage of magnetic flux becomes unbalanced. Because of this, the detection accuracy decreases.

For example, in a four-phase coil, there are four types of salient poles in which the tooth phase shift with respect to the reference position is 0, p / 4, 2p / 4, 3p / 4 (p is the tooth pitch). The stator is provided with multiple salient poles of the same type, and the coils wound around these salient poles are connected in series to average the induced voltage in the coils wound around the salient poles and improve the accuracy of the detection signal. I am letting you.

When the stator has a structure in which two stator plates are stacked, the number of salient poles of the same type is large, so that the salient poles used for averaging are large and the detection accuracy is improved.

On the other hand, in the case where the stator is composed of one stator plate, the number of salient poles of the same type is small, and it is difficult to improve the detection accuracy.

In order to solve this, if the gap between the rotor and the stator is increased, the harmonic component of the induced voltage in the coil is reduced and the ripple of the detection signal can be reduced. However, when the gap is increased, the leakage magnetic flux is increased.

The present invention has been made to solve such a problem, and solves a problem specific to a magnetic resolver having a single stator plate and a sin phase coil and a cos phase coil,
The purpose is to obtain a highly accurate detection signal.

<Means for Solving the Problems> In the present invention, one stator plate is provided, and the coil wound around the salient poles of this stator plate is excited by a sin phase voltage and a cos phase voltage. There is a coil that is used for a magnetic resolver that obtains a phase modulation type rotation detection signal based on the induced voltage of these coils, is composed of a magnetic material, and is fixed to at least one of the rotor and stator, It is arranged at a position that covers the gap between the rotor and the stator and guides the leakage magnetic flux that flows out of the stator and follows the path that does not pass through the gap to flow into the rotor, or flows out from the rotor and flows through the path that does not pass through the gap. A magnetic resolver having a magnetic flux guide member that guides a leaked magnetic flux that follows and flows into the stator.

<Operation> In the present invention as described above, among the magnetic fluxes generated by the sin-phase coil and the cos-phase coil, the leakage magnetic flux that flows out of the stator and follows a path that does not pass through the gap is guided by the magnetic flux guide member and made to flow into the rotor. To be Leakage magnetic flux that flows out of the rotor and follows a path that does not pass through the gap is also guided by the magnetic flux guide member and made to flow into the stator.

<Example> Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which (a) is a sectional view taken along line XX of FIG. (B) and (b) is a sectional view taken along line YY of (a). is there.

In the figure, 10 is a rotor having a cylindrical shape and teeth 11 formed on the inner circumference at a constant pitch p.

Reference numeral 20 denotes a stator arranged inside the rotor 10, which is composed of one stator plate.

The stator plate 20 is provided with 4n (n is an integer), for example, 16 salient poles 21 _{1 to} 21 ₄ , 22 _{1 to} 22 ₄ , 23 ₁ to 23 ₄ , 24 _{1 to} 24 ₄ . Teeth 25 with a pitch p facing the teeth 11 are formed at the tips of these salient poles. The phases of the teeth formed on the salient poles are shifted by p / 4 according to the arrangement order of the salient poles. For example,
The phase of the teeth of salient poles 22 ₁ , 23 ₁ , 24 ₁ with respect to the teeth of salient pole 21 ₁ is
They are offset by p / 4, 2p / 4, 3p / 4 respectively.

The salient poles 21 _{1 to} 21 ₄ , 22 _{1 to} 22 ₄ , 23 ₁ to 23 ₄ , and 24 _{1 to} 24 ₄ are referred to as 0 ° salient pole, 90 ° salient pole, 180 ° salient pole, and 270 ° salient pole, respectively.

The salient poles 21 _{1 to} 21 ₄ , 22 _{1 to} 22 ₄ , 23 ₁ to 23 ₄ , 24 _{1 to} 24 ₄ are
Coils 26 _{1 to} 26 ₄ , 27 _{1 to} 27 ₄ , 28 _{1 to} 28 ₄ , 29 ₁ to 2
9 ₄ is wound.

The winding direction of each coil is clockwise when viewed from the outer circumference of the stator.

And if the coil 26 _{1-26 4,} and if 27 _{1-27 4} 28 _{1-28 4} What happened, 29 _{1-29 4} How to each series or are connected in parallel 0 ° phase coil, 90 ° phase coil, 180 ° A phase coil and a 270 ° phase coil are configured.

30 is the coil wound around each salient pole with Ecosωt or Esinω
It is a drive source that is excited by a voltage signal of t (E is voltage amplitude, ω is angular velocity, and t is time).

Reference numeral 31 is an arithmetic circuit for calculating the rotation of the rotor 10 based on the voltage induced in each coil.

In Fig. 1, the excitation coil and the detection coil are shown as 26 _{1 to} 26 ₄ , 27 ₁
To 27 _4, 28 ₁ to 28 are shown also serves as at _4, 29 ₁ to 29 _4.

Reference numeral 40 is a rotor ring fixed to the rotor 10, and 41 and 42 are electromagnetic steel plates fixed to the rotor ring 40 and arranged at positions covering the gap between the rotor and the stator.

50 is a stator ring fixed to the stator 20, 51, 52
Is fixed to the stator ring 50 and part of it is a magnetic steel plate
It is a magnetic steel sheet that overlaps with 41 and 42.

 Here, a specific circuit configuration will be described.

FIG. 2 is an explanatory view showing the connection between each coil and the drive source. In this figure, the salient poles are shown in a developed view.

In the figure, L ₀ , L ₉₀ , L ₁₈₀ , and L ₂₇₀ are 0 ° phase coil, 90 ° phase coil, 180 ° phase coil, and 270 ° phase coil, respectively. Although only four salient poles are shown in the figure, these four
One salient pole is a set of 0 ° salient pole, 90 ° salient pole, 180 ° salient pole, and 270 ° salient pole, and each is shown as one salient pole.

The coils L ₀ and L ₁₈₀ are connected in parallel with the driving source that generates the voltage signal Ecosωt, and the coils L ₉₀ and L ₂₇₀ are connected to the voltage signal Esinωt.
It is connected in parallel with the drive source that generates t.

By connecting such a driving source, the magnetic force lines shown by the solid line and the magnetic force lines shown by the broken line in FIG. 3 are alternately generated. As a result, the voltage signals S are applied to the coils L ₀ , L ₉₀ , L ₁₈₀ , and L ₂₇₀ , respectively.
₁ , S ₂ , S ₃ , and S ₄ occur. Each of the signals S _{1 to} S ₄ is given by the following equation.

S ₁ = (1 + mcosθ) cosωt−k (1 + msinθ) sinωt
+ K (1-msinθ) sinωt S ₂ = (1-mcosθ) cosωt + k (1 + msinθ) sinωt
−k (1-msinθ) sinωt S ₃ = (1 + msinθ) sinωt−k (1 + mcosθ) cosωt
+ K (1-mcosθ) cosωt S ₄ = (1-msinθ) sinωt + k (1 + mcosθ) cosωt
-K (1-msinθ) cosωt θ: Rotation angle of the rotor, k, m: constants, the second and third terms on the right side of each equation are obtained by excitation other than the excitation performed to obtain the signal of the first term. Is the generated interference component.

 FIG. 4 is a diagram showing a specific configuration of the arithmetic circuit.

In the figure, 311 is a circuit for adjusting the phase and gain of the sin-phase and cos-phase excitation signals.

As shown in the figure, the arithmetic circuit calculates the detection signal S by performing the following calculation.

S = S ₁ −S ₃ + S ₂ −S ₄ = 2mcos θcosωt + 2msin θsinωt −4kmsin θsinω
t-4km cos θcosωt = 2m {(1-2k) cosθcosωt + (1-2k) sin θsin
ωt} = 2m (1-2k) cos (θ−ωt) Theoretically, the residual carrier component is S ₁ −
It should be erased by the operation S ₃ + S ₂ −S ₄ . However, in reality, the residual carrier component Acos (ωt−φ) is generated due to a mechanical error such as circularity or coaxiality of the rotor and the stator, and the detection signal S is expressed by the following equation.

S = 2m (1-2k) cos (θ-ωt) + Acos (ωt-φ) A: constant Therefore, the signal Acos whose phase and amplitude are adjusted by the circuit 311
The residual carrier component is removed by adding (ωt−φ + π) to the detection signal S.

The detection signal S is a signal whose phase is modulated according to the rotation angle of the rotor, the rotation position of the rotor is detected from the phase of this signal, and the rotation speed is detected from the frequency.

 Also, the leakage flux is guided as follows.

FIG. 5 is a block diagram of the magnetic circuit of the resolver of FIG.

The direction of the magnetic flux is from the stator to the rotor.

Most of the magnetic flux flowing out of the stator 20 flows into the rotor 40 through the air gap g. However, at the same time, magnetic leakage occurs from the stator 20. Electrical steel sheet
By arranging 41, 42, 51, 52 so as to cover the portion where magnetic leakage occurs, the leakage magnetic flux passes through the electromagnetic steel sheet, and the rotor 10
Be made to flow into. This reduces the leakage flux and eliminates the leakage flux imbalance.

Here, the principle of increasing the amount of change in the magnetic flux of each coil when the rotor of the magnetic resolver rotates by providing the magnetic flux guide member such as an electromagnetic steel plate will be described. It will be explained using a formula generally known in electromagnetics.

The magnetic resistance R _g of the gap between the rotor and the stator of the magnetic resolver is given by the following equation.

R _g = R _g1 + R _g2 sin θ + R _g3 = (R _g1 + R _g3 ) [1+ {R _g2 / (R _g1 + R _g3 )} ・ sin
θ]… In the above formula, R _g1 + R _g2 sin θ is the magnetic resistance as the signal, and R
_g1 is the bias amount, R _g2 is the amplitude of the modulation component, and θ is the phase shift between the rotor and stator teeth. R _g3 is the magnetic resistance due to the leakage flux.

R _g3 is reduced by providing the magnetic flux guide member. As a result, {R _g2
The value of / (R _g1 + R _g3 )} increases.

 The magnetic flux φ of the coil is given by the following equation.

φ = F / (R _c + R _g ) F: Magnetomotive force, R _c : Magnetic reluctance of the core Therefore, when the value of {R _g2 / (R _g1 + R _g3 )} increases, the amount of change in the magnetic flux φ of the coil also increases. Become. As a result, by providing the magnetic flux guide member, the amount of change in the magnetic flux of the coil when the rotor of the magnetic resolver rotates increases.

In the present invention, since the magnetic flux guide member is provided, the gap can be made larger than in the conventional example in which the magnetic flux guide member is not provided. As a result, in the present invention, the harmonic component of the induced voltage of the coil can be reduced as compared with the conventional example.

The rotor and the electromagnetic steel plate may be installed on one of the rotor and the stator.

Further, the number of electromagnetic steel plates is not limited to one, and may be laminated. Further, permalloy may be used instead of the electromagnetic steel sheet.

Further, the magnetic rotor is not limited to the outer rotor type magnetic resolver, but may be an inner rotor type configuration.

<Effect> According to the present invention, since the electromagnetic steel sheet is installed in the portion where magnetic leakage occurs, the leakage magnetic flux is guided by the electromagnetic steel sheet and flows into the core. As a result, the leakage flux of the magnetic resolver is reduced, and the imbalance in the leakage of the magnetic flux is removed, so that the detection accuracy of the magnetic resolver can be improved.

As described above, according to the present invention, it is possible to solve the problem peculiar to the magnetic resolver in which one stator plate is used and the rotation detection signal is obtained by the sin phase coil and the cos phase coil.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2, FIG.
FIG. 5 is a diagram showing a configuration example of a main part of the magnetic resolver of FIG. 1, and FIG. 3 is an operation explanatory diagram of the magnetic resolver of FIG. 10 ...... rotor, 11, 25 ...... teeth, 20 ...... stator, 21 ₁ to 21
₄ , 22 _{1 to} 22 ₄ , 23 ₁ to 23 ₄ , 24 _{1 to} 24 ₄ ...... salient pole, 26 ₁ to 2
6 ₄ , 27 _{1 to} 27 ₄ , 28 _{1 to} 28 ₄ , 29 _{1 to} 29 ₄ …… Coil, 30 ……
Drive source, 31 ... Arithmetic circuit. 40 …… Rotoring, 50 ……
Stator ring, 41, 42, 51, 52 ... Electromagnetic steel sheet.

Continuation of the front page (56) Reference JP-A-1-155210 (JP, A) JP-A-1-270615 (JP, A) Actually opened 63-128465 (JP, U) Actually opened 58-65572 (JP , U)

Claims (1)

[Scope of utility model registration request] 1. A single stator plate is provided, and coils wound around salient poles of the stator plate include a coil excited by a sin phase voltage and a coil excited by a cos phase voltage,
It is used for a magnetic resolver that obtains a phase modulation type rotation detection signal based on the induced voltage of these coils, and it is made of a magnetic material and is fixed to at least one of the rotor and stator. It is arranged in a position to cover the gap and guides a leakage magnetic flux that flows out of the stator and follows a path that does not pass through the gap and flows into the rotor, or guides a leakage magnetic flux that flows out of the rotor and that follows a path that does not pass through the gap. A magnetic resolver having a magnetic flux guide member for flowing into a stator.