JP3693280B2 - Resolver assembly equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a resolver assembling apparatus for assembling a resolver used in a position detector of a machine tool.
[0002]
[Prior art]
As shown in FIG. 2, the reluctance type resolver is disposed on the outer periphery of the rotor portion 20 made of a cylindrical magnetic body attached eccentrically with respect to a predetermined rotation shaft, and on the rotation shaft 21. The stator portion 30 is made of a magnetic material having four pole teeth in two orthogonal directions. Here, windings 32, 33, 34, and 35 are wound around the pole teeth of the stator unit 30, and current detection resistors 42, 43, 44, and 45 corresponding to the windings are connected to the pole teeth of the stator unit 30. Further, the predetermined rotation shaft of the rotor unit 20 is assembled so as to be the center (shape center 31) of the inner periphery of the pole teeth of the stator unit 30. Conventionally, this reluctance resolver has been assembled by mechanically aligning the outer periphery of the housing of the stator portion 30 and the rotor portion 20. That is, the tolerance of the processing accuracy of the stator part 30 is managed, and the housing outer periphery of the rotor part and the stator part is applied to the reference surface based on the processing precision, and then non-defective products are selected by product inspection.
[0003]
Hereinafter, the position detection using this reluctance type resolver will be specifically described. FIG. 2 is a front view of a reluctance resolver in which the rotor unit 20 is fixed to the rotation shaft 21 that is shifted by Δx from the shape center 31 (position that should originally be the rotation shaft), and FIG. 3 is a position detection of the reluctance resolver. FIG. 4 is a block diagram showing an example of a circuit for performing the above.
[0004]
In FIG. 3, a timing generator 40 generates two signals, ie, a synchronized excitation timing signal EX1 and an AD start signal ST. The excitation circuit 41 generates an excitation signal EX2, which is a rectangular wave signal obtained by current amplification of the excitation timing signal EX1.
[0005]
The cylindrical rotor portion 20 is eccentrically fixed to the housing so as to rotate about the rotation shaft 21. The stator part 30 consists of magnetic bodies, such as a silicon steel plate, and has a convex part as four pole teeth. Moreover, when the windings 32 to 35 are wound around the pole teeth and the rotor portion 20 rotates, the air gap between the rotor portion 20 and each pole tooth of the stator portion 30 changes, and the rotor portion 20 An inductance change corresponding to a trigonometric function for one period per rotation is caused in each of the windings 32 to 35.
[0006]
As shown in FIG. 3, the excitation signal EX2 is input to one end of the windings 32 to 35, and the corresponding current detection resistors 42 to 45 are connected to the other end. The windings 32 to 35 detect a change in inductance accompanying the rotation of the rotor unit 20 as a change in current, and the current detection resistors 42 to 45 detect this change in current as a change in voltage. Output voltages generated in the current detection resistors 42 to 45 are respectively input to differential amplifiers 46 and 47, and are differentially amplified to become signals A1 and B1. The A / D converters 48 and 49 convert the signals A1 and B1 into digital signals A and B at the falling edge of the AD start signal ST. The interpolation calculator 50 calculates and outputs a target detection angle θ by taking an arc tangent (inverse tangent) as a result of dividing the digital signals A and B.
[0007]
Here, if the rotating shaft 21 of the rotor unit 20 is deviated from the shape center 31 of the pole teeth of the stator unit 30 during assembly of the reluctance type resolver, an error in detection angle occurs due to this axial deviation. That is, originally, the digital signals A and B that are resolver detection signals should be accurate sine functions (sin), but if there is an axis misalignment, the second harmonic as shown in the following [Equation 1]. It becomes a function including a wave.
[0008]
[Expression 1]
A = V1 · SIN (θ) −V2 · COS (θ · 2 + α)
B = V1 · COS (θ) + V2 · COS (θ · 2 + α)
Here, θ is the rotation angle of the input shaft of the resolver, V1 is a coefficient indicating the amplitude of the fundamental wave component determined by the characteristics of the resolver, and V2 is the amplitude of the second harmonic component of the resolver. Α is a coefficient indicating the phase of the second harmonic component of the resolver. Here, V2 and α are determined by the axial deviation characteristics of the stator portion 30 and the rotor portion 20 of the resolver. Therefore, when division is performed based on the digital signals A and B and the arc tangent is calculated, when the rotor unit 20 makes one rotation, an error of one cycle and three cycles per rotation are obtained with respect to the rotation cycle. Component error.
[0009]
[Problems to be solved by the invention]
As described above, in the conventional resolver assembly, the tolerance of the resolver component processing is managed, and the outer periphery of the housing of the rotor portion and the stator portion is aligned with the reference plane based on the processing accuracy. The rotating shaft of the part is the center of the outer periphery of the stator part. Here, if the center of the outer periphery of the stator portion and the center of the inner periphery of the pole teeth (shape center) are shifted due to a processing error of the stator portion, the rotation axis of the rotor portion is deviated from the shape center of the stator portion. As a result, an error occurs in the detection angle by the resolver, and this resolver is selected as a non-defective product. In this case, there is a problem that the yield is deteriorated due to unexpected processing accuracy failure such as burrs.
[0010]
In order to increase the yield, the shape of the stator portion may be processed with high accuracy, but there is a problem in that this increases costs.
[0011]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a resolver assembling apparatus capable of improving the yield without increasing the cost.
[0012]
[Means for Solving the Problems]
The present invention for solving the problems of the above-described conventional example is a stator comprising a rotating shaft of a rotor portion which is made of a magnetic material and is eccentrically fixed around a predetermined rotating shaft, and pole teeth wound with windings. A resolver comprising: a detector that detects a relative position of the portion of the pole tooth relative to the inner peripheral center of the pole tooth as an amount of axial deviation; and an adjuster that adjusts the relative position based on the amount of axial deviation detected by the detector. In the assembling apparatus, the detector detects a change in inductance generated in the winding of the stator portion by the rotation of the rotor portion and performs Fourier transform, and the amplitude of the three period components per rotation of the resolver of the inductance change. And a Fourier transformer for detecting the phase and a phase, and an arithmetic unit for detecting the amount of axial deviation with respect to the rotation axis of the rotor unit based on the amplitude and phase output from the Fourier transformer. To have.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing a resolver assembling apparatus according to an embodiment of the present invention. As shown in FIG. 1, the resolver assembling apparatus according to the embodiment of the present invention includes an amplitude calculator 2, an interpolation calculator 3, a storage unit 4, a Fourier transformer 5, and a first calculator. 6, a second computing unit 7, and an XY table 8. Here, the amplitude calculator 2, the interpolation calculator 3, the memory 4, the Fourier transformer 5, the first calculator 6, and the second calculator 7 correspond to detectors, XY Table 8 corresponds to a regulator.
[0015]
Hereinafter, each of these parts will be described. The amplitude calculator 2 performs the calculation shown in [Equation 2] based on the digital signals A and B output from the resolver 1 to be assembled, and outputs the amplitude R. .
[0016]
[Expression 2]
R = √ (A ² + B ² )
The interpolation calculator 3 performs the calculation shown in [Equation 3] based on the digital signals A and B output from the resolver 1 to be assembled, and outputs the rotational position P.
[0017]
[Equation 3]
P = TAN ⁻¹ (A / B) / (2 · π) · N when A ≧ 0 and B> 0
When B <0, P = (π + TAN ⁻¹ (A / B)) / (2 · π) · N
When A <0 and B ≧ 0, P = (3/2 · π-TAN ⁻¹ (B / A)) / (2 · π) · N
Where N is the number of samples per resolver revolution.
The storage unit 4 stores N pieces of the rotational position P of the resolver and the amplitude R corresponding to the resolver, and outputs a completion signal Q when all the N pieces of data are set.
[0019]
Upon receiving the completion signal Q, the Fourier transformer 5 calculates and outputs the amplitude G and the phase β of the three period components per revolution of the resolver included in the amplitude R by a generally well-known method. The amplitude G obtained here is proportional to the amount of axial deviation of the stator portion with respect to the rotor portion, and the phase β indicates the direction of the axial deviation, so that the first and second calculators 6 and 7 perform unit conversion and XY. Convert to plane coordinates.
[0020]
That is, the first calculator 6 performs the calculation shown in [Equation 4] and outputs the amount X of axial deviation in the X-axis direction.
[0021]
[Expression 4]
X = K ・ G ・ SIN (β)
The second calculator 7 performs the calculation shown in [Equation 5] and outputs the amount Y of axial deviation in the Y-axis direction.
[0022]
[Equation 5]
Y = K ・ G ・ COS (β)
In [Equation 4] and [Equation 5], K is a unit conversion coefficient determined by the resolver structure. The XY table 8 moves the stator unit 30 with respect to the rotor unit 20 using the axis deviation amounts X and Y as command values, and corrects this axis deviation.
[0023]
That is, the resolver assembling apparatus according to the embodiment of the present invention temporarily assembles the resolver 1 on the XY table 8, Fourier-transforms the signal output from the resolver 1 to acquire a harmonic component, Based on the wave component, the amount of axial deviation is detected, and the relative position between the rotor portion 20 and the stator portion 30 of the resolver 1 is adjusted to perform actual assembly.
[0024]
As described above, according to the resolver assembling apparatus according to the embodiment of the present invention, the axial deviation amount of the stator portion 30 with respect to the rotor portion 20 is calculated based on the three period components per one revolution of the resolver of the amplitude of the signal output from the resolver. Therefore, a resolver with a low position detection error can be assembled. Further, since the axis deviation is corrected with the value detected using the actual part, high-precision part processing is not required, and the resolver part can be made inexpensive. Further, even if there is a processing defect in a part, it can be assembled with high accuracy without being affected by it, the position detection accuracy of the assembled resolver can be improved, and the yield can be improved.
[0025]
【The invention's effect】
According to the present invention, the detector that detects the amount of shaft misalignment between the rotor portion and the stator portion detects the amount of shaft misalignment based on the three-cycle components per resolver rotation of the signal output by the resolver to be assembled. In addition, since the misalignment is corrected, even if there is a machining defect in a part, it can be assembled with high accuracy, and the yield can be improved without increasing the cost of machining the part.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram of a resolver assembling apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a structure of a 1 × reluctance resolver in which a rotor portion and a stator portion are misaligned.
FIG. 3 is a configuration block diagram showing an example of a position detection circuit of a general reluctance resolver.
FIG. 4 is a timing chart of signals in a position detection circuit of a general reluctance resolver.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Resolver, 2 Amplitude calculator, 3 Interpolation calculator, 4 Memory | storage device, 5 Fourier transformer, 6 1st calculator, 7 2nd calculator, 8 XY table, 20 Rotor part, 21 Rotating shaft, 30 Stator part, 31 shape center, 32 to 35 windings, 40 timing generator, 41 excitation circuit, 42 to 45 current detection resistor, 46 and 47 differential amplifier, 48 and 49 AD converter, 50 interpolation calculator.

Claims (2)

A relative position between the rotation shaft of the rotor portion, which is made of a magnetic material and is eccentrically fixed around a predetermined rotation shaft, and the inner peripheral center of the pole teeth of the stator portion having the pole teeth wound with windings is an axis. In a resolver assembling apparatus comprising a detector that detects the amount of deviation, and an adjuster that adjusts the relative position based on the amount of axial deviation detected by the detector.
The detector detects a change in inductance generated in the winding of the stator portion due to the rotation of the rotor portion and performs Fourier transform, and calculates the amplitude and phase of the three period components per resolver rotation of the inductance change. A Fourier transformer to detect;
A resolver assembling apparatus comprising: an arithmetic unit that detects an amount of axial deviation of the rotor portion with respect to the rotation axis based on an amplitude and a phase output from the Fourier transformer. A relative position between the rotation shaft of the rotor portion, which is made of a magnetic material and is eccentrically fixed around a predetermined rotation shaft, and the inner peripheral center of the pole teeth of the stator portion having the pole teeth wound with windings is an axis. In a resolver assembling apparatus comprising: a detector that detects the amount of deviation; and an adjuster that adjusts the relative position based on the amount of axial deviation detected by the detector.
An amplitude calculator that calculates based on the digital signals A and B output from the resolver to be assembled and outputs the amplitude R, and an interpolation calculator that calculates the rotational position P based on the digital signals A and B And the rotational position P and the amplitude R corresponding thereto are stored in association with each other, and a storage device that outputs a completion signal Q when all of the N pieces of data are set, and an amplitude when the completion signal Q is received. A Fourier transformer that calculates and outputs an amplitude G and a phase β of three period components per revolution of the resolver included in R, and an axis deviation amount X in the X-axis direction is determined by the amplitude G, the phase β, and the resolver structure. From unit conversion factor K
X = K ・ G ・ SIN (β)
The first arithmetic unit calculated by
Y = K ・ G ・ COS (β)
A second computing unit calculated by
An resolver assembling apparatus comprising: an XY table that moves the stator portion with respect to the rotor portion using the axial deviation amounts X and Y as command values and corrects the axial deviation.

Images