JP2018121404A - Resolver stator, resolver, and direct drive motor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resolver stator and the like capable of obtaining signals of a plurality of periods from one cycle in which an eccentric rotor makes one rotation.SOLUTION: A stator 22 used in combination with an eccentric rotor 21, includes: a first coil group having coils C,C,...,Cprovided along a rotational direction of the eccentric rotor 21; a multi-cycle signal output unit that outputs a signal of a plurality of periods with respect to one cycle in which the eccentric rotor 21 rotates once based on an electric signal output from the first coil group; a second coil group having coils C,C, ...,Cprovided separately from the coils C,C,...,Cand provided along the rotation direction of the eccentric rotor 21; and a one cycle signal output unit for outputting a signal of one period for one cycle based on an electric signal output from the second coil group, The first coil group and the second coil group are provided along a circumference on the same plane orthogonal to the rotation axis of the eccentric rotor 21.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resolver stator, a resolver, and a direct drive motor system.

  A resolver that changes the reluctance of a coil provided in a stator according to the rotation angle of the rotor by using an eccentric rotor is known (for example, Patent Document 1).

JP 2006-090509 A

  However, the change in reluctance due to the use of the eccentric rotor only changes the output pattern of one cycle corresponding to one rotation of the rotor, and does not function as a mechanism for obtaining a signal (harmonic) of a plurality of cycles from one cycle. It was.

  An object of the present invention is to provide a resolver stator, a resolver, and a direct drive motor system that can obtain signals of a plurality of cycles from one cycle in which an eccentric rotor makes one rotation.

  In order to achieve the above object, a resolver stator according to the present invention is a resolver stator used in combination with an eccentric rotor, and includes a first coil having eight or more coils provided along the rotation direction of the eccentric rotor. A group, a multi-cycle signal output unit that outputs a signal of a plurality of cycles for one cycle in which the eccentric rotor makes one rotation based on an electrical signal output from the first coil group, and the eight or more coils Is provided separately and has a second coil group having a plurality of coils provided along the rotation direction of the eccentric rotor, and an electric signal output from the second coil group for the one period. A first-cycle signal output unit that outputs a signal of one cycle, and the first coil group and the second coil group are arranged along a circumference on the same plane orthogonal to a rotation axis of the eccentric rotor. Setting It is.

  Therefore, since the multi-cycle signal output unit outputs a multi-cycle signal for one cycle in which the eccentric rotor makes one rotation based on the electrical signal output from the first coil group, one cycle in which the eccentric rotor makes one rotation. A signal having a plurality of cycles can be obtained from Further, since the one-cycle signal output unit outputs one cycle signal for one cycle in which the eccentric rotor makes one rotation based on the electrical signal output from the first coil group, one cycle in which the eccentric rotor makes one rotation A signal of one period can be obtained. In addition, since the first coil group and the second coil group are provided along the same circumference orthogonal to the rotation axis of the eccentric rotor, the first coil group and the second coil group in the radial direction around the rotation axis. The coil group can be collected more compactly. In addition, the first coil group and the second coil group are alternately arranged along a circumference on the same plane orthogonal to the rotation axis, so that the first coil group and the second coil group are arranged in the direction along the rotation axis. The two coil groups can be combined more compactly.

  In the resolver stator of the present invention, the first coil group includes a first phase in which a plurality of coils that output a first electric signal are connected in series, and an opposite side of the first phase across the rotating shaft. A second phase in which a plurality of coils that are provided and output a second electrical signal are connected in series; and a third electrical signal that is disposed in a positional relationship of 90 degrees with the first phase around the rotation axis. A third phase in which a plurality of coils that output a signal are connected in series, and a plurality of coils that are provided on the opposite side of the first phase across the rotating shaft and that output a fourth electrical signal are connected in series. A multi-phase signal output unit that inverts one of the two electrical signals of the first phase and the second phase to synthesize the two electrical signals. Of the two electrical signals, the third phase electrical signal and the fourth phase electrical signal, Write inverts the synthesizing the two electrical signals.

  Therefore, one of the two electric signals of the first phase and the second phase is inverted to synthesize the two electric signals, and the third phase electric signal and the fourth phase electric signal are combined. By inverting one of the two electric signals and synthesizing the two electric signals, it is possible to obtain an output that can more reliably detect a change in the electric signal according to the rotation angle of the eccentric rotor. In addition, even if a noise component is included in the electrical signal output from the coil, the influence of this noise component can be suppressed by inverting and synthesizing one of the signals in the oppositely arranged phase. it can. In addition, since a plurality of coils are provided in each phase, it is possible to extract second-order or higher-order components included in the electrical signal output from the coils according to the rotation of the eccentric rotor.

  In the resolver stator of the present invention, the first coil group and the second coil group have the same number of coils.

  Therefore, the arrangement of the coils can be made uniform around the rotation axis.

  In order to achieve the above object, a resolver according to the present invention includes the eccentric rotor and the resolver stator.

  Accordingly, it is possible to provide a resolver capable of obtaining the effects of the resolver stator, such as being able to obtain signals of a plurality of periods from one period in which the eccentric rotor makes one rotation.

  In order to achieve the above object, a direct drive motor system of the present invention includes the resolver, a direct drive motor having an output shaft to which the eccentric rotor is fixed, a rotation angle indicated by the signal of one cycle, and the plurality of And a detection unit that detects a rotation angle of the output shaft based on a rotation angle indicated by a cycle signal.

  Therefore, in the configuration for detecting the rotation angle of the output shaft of the direct drive motor, the direct drive capable of obtaining the effects exhibited by the resolver, such as being able to obtain a signal of a plurality of cycles from one cycle in which the eccentric rotor of the resolver makes one rotation. A motor system can be provided.

  According to the resolver stator, resolver, and direct drive motor system of the present invention, a signal having a plurality of cycles can be obtained from one cycle in which the eccentric rotor makes one rotation.

FIG. 1 is a diagram illustrating a main configuration example of a resolver according to the first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration example of a circuit unit connected to the coil. FIG. 3 is a schematic diagram illustrating a wiring example of the first coil group. FIG. 4 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the first phase. FIG. 5 is a graph showing an example of a voltage waveform indicated by one current signal different from that in FIG. 4 among the coils provided in the first phase. FIG. 6 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 4 and 5 among the coils provided in the first phase. FIG. 7 is a graph illustrating an example of a voltage waveform of the first sin θ signal. FIG. 8 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the second phase. FIG. 9 is a graph showing an example of a voltage waveform indicated by one current signal different from that in FIG. 8 among the coils provided in the second phase. FIG. 10 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 8 and 9 among the coils provided in the second phase. FIG. 11 is a graph illustrating an example of a voltage waveform of the first (−sin θ) signal. FIG. 12 is a graph illustrating an example of an output voltage waveform of the first differential amplifier circuit. FIG. 13 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the third phase. FIG. 14 is a graph showing an example of a voltage waveform indicated by one current signal different from that in FIG. 13 among the coils provided in the third phase. FIG. 15 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 13 and 14 among the coils provided in the third phase. FIG. 16 is a graph illustrating an example of a voltage waveform of the first cos θ signal. FIG. 17 is a graph showing an example of a voltage waveform indicated by one current signal among coils provided in the fourth phase. 18 is a graph showing an example of a voltage waveform indicated by one current signal different from that in FIG. 17 among the coils provided in the fourth phase. FIG. 19 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 17 and 18 among the coils provided in the fourth phase. FIG. 20 is a graph illustrating an example of a voltage waveform of the first (−cos θ) signal. FIG. 21 is a graph illustrating an example of an output voltage waveform of the second differential amplifier circuit. FIG. 22 is a schematic diagram illustrating a wiring example of the second coil group. FIG. 23 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the fifth phase. FIG. 24 is a graph illustrating an example of a voltage waveform indicated by one current signal different from that in FIG. 23 among the coils provided in the fifth phase. FIG. 25 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 23 and 24 among the coils provided in the fifth phase. FIG. 26 is a graph illustrating an example of a voltage waveform of the second sin θ signal. FIG. 27 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the sixth phase. FIG. 28 is a graph illustrating an example of a voltage waveform indicated by one current signal different from that in FIG. 27 among the coils provided in the sixth phase. FIG. 29 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 27 and 28 among the coils provided in the sixth phase. FIG. 30 is a graph illustrating an example of a voltage waveform of the second (−sin θ) signal. FIG. 31 is a graph illustrating an example of an output voltage waveform of the third differential amplifier circuit. FIG. 32 is a graph showing an example of a voltage waveform indicated by one current signal among the coils provided in the seventh phase. FIG. 33 is a graph illustrating an example of a voltage waveform indicated by one current signal different from that in FIG. 32 among the coils provided in the seventh phase. FIG. 34 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 32 and 33 among the coils provided in the seventh phase. FIG. 35 is a graph illustrating an example of a voltage waveform of the second cos θ signal. FIG. 36 is a graph showing an example of a voltage waveform indicated by one current signal among coils provided in the eighth phase. FIG. 37 is a graph showing an example of a voltage waveform indicated by one current signal different from that in FIG. 36 among the coils provided in the eighth phase. FIG. 38 is a graph showing an example of a voltage waveform indicated by one current signal different from those in FIGS. 36 and 37 among the coils provided in the eighth phase. FIG. 39 is a graph illustrating an example of a voltage waveform of the second (−cos θ) signal. FIG. 40 is a graph illustrating an example of an output voltage waveform of the fourth differential amplifier circuit. FIG. 41 is a cross-sectional view of the direct drive motor according to the second embodiment. FIG. 42 is a block configuration diagram including a direct drive motor system with a driver unit according to the third embodiment. FIG. 43 is a flowchart describing a CPU position detection processing routine. FIG. 44 is a block diagram of a direct drive motor system with a driver unit, which is a modification of the third embodiment.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings, but the present invention is not limited thereto. The requirements of the embodiments described below can be combined as appropriate. Some components may not be used.

(Embodiment 1)
FIG. 1 is a diagram illustrating a main configuration example of a resolver 20 according to the first embodiment of the present invention. The resolver 20 includes an eccentric rotor 21 and a stator 22. The resolver 20 is configured such that the reluctance of the gap between the eccentric rotor 21 and the stator 22 changes depending on the rotation angle position of the eccentric rotor 21, and the fundamental wave component of the reluctance change becomes one cycle by one rotation of the eccentric rotor 21. Resolver 20. Specifically, the outer diameter center and inner diameter center of the stator 22 and the outer diameter center of the eccentric rotor 21 coincide with the rotation center O ₁ of the direct drive motor, but the inner diameter center O ₂ of the eccentric rotor 21 is the rotation center O _1. Is decentered by Δx. More specifically, the annular eccentric rotor 21 is formed by laminating, for example, an annular iron plate formed so that the radial thickness continuously changes.

The stator 22 is provided on the inner peripheral side of the eccentric rotor 21. The stator 22 has, for example, a predetermined number (for example, 24) of stator poles 23 provided so as to protrude from the annular base portion toward the eccentric rotor 21 side (outer peripheral side). The predetermined number of stator poles 23 are arranged in a ring at regular intervals. Coil bobbin 24 wound to C ₂₄ coils C _1, respectively is mounted on the stator poles 23. That is, the number to C ₂₄ number of coils C ₁ of the stator poles 23 are identical.

The stator 22 functions as an iron core of the coils C ₁ to C ₂₄ and is configured by using laminated iron plates or the like. However, the material of the stator 22 is not limited to this, and is a material that functions as an iron core. If there is, it can be adopted as appropriate. The coil bobbin 24 is configured using a nonmagnetic material having moderate elasticity. The material of the coil bobbin 24 is, for example, a thermoplastic resin that can be injection-molded, such as styrene resin, polycarbonate resin, polyphenylene ether resin, nylon, polybutylene terephthalate resin, but is not limited thereto. It can be changed.

FIG. 2 is a block diagram showing a configuration example of a circuit portion 30 connected from the coil C ₁ and C _24. The coils C ₁ to C ₂₄ in the _first embodiment include a first coil group G ₁ and a second coil group G ₂ . The first coil group G _1, the common terminal COM1, and is connected to the current / voltage converter 41a and the two-phase signal converter 42a. The second coil group G _2, the common terminal COM2, is connected to a current / voltage converter 41b and the two-phase signal converter 42b. The common terminals COM1 and COM2 are terminals for supplying an excitation signal to the connected coil group. The current / voltage converters 41a and 41b are circuits having a detection resistor R that converts a current signal output from a connected coil group into a voltage signal (see FIGS. 3 and 22). The two-phase signal converter 42a includes a first differential amplifier circuit A ₁ and a second differential amplifier circuit A ₂ for outputting the output of the first coil group G ₁ as a two-phase signal (see FIG. 3). . The two-phase signal converter 42b includes a third differential amplifier circuit A ₃ and a fourth differential amplifier circuit A ₄ for outputting the output of the second coil group G ₂ as a two-phase signal (see FIG. 22). . The first differential amplifier circuit A ₁ , the second differential amplifier circuit A ₂ , the third differential amplifier circuit A ₃ , and the fourth differential amplifier circuit A ₄ receive one of the two input signals. It is a circuit that inverts and outputs two signals. Specifically, the first differential amplifier circuit A ₁ , the second differential amplifier circuit A ₂ , the third differential amplifier circuit A ₃ , and the fourth differential amplifier circuit A ₄ are, for example, operational amplifiers.

The first coil group G ₁ and the second coil group G ₂ each have a plurality of coils provided along the rotation direction of the eccentric rotor 21. The first coil group G ₁ includes eight or more coils (for example, 12 coils C ₁ , C ₃ , C ₅ , C ₇ , C ₉ , C ₁₁ , C ₁₃ , C ₁₅ , C ₁₇ , and the like shown in FIG. C ₁₉ , C ₂₁ , C ₂₃ ). The outputs of the coils C ₁ , C ₃ , C ₅ , C ₇ , C ₉ , C ₁₁ , C ₁₃ , C ₁₅ , C ₁₇ , C ₁₉ , C ₂₁ , C ₂₃ constituting the first coil group G ₁ are: The signals are synthesized so as to be a signal having a period of n times (for example, n = 3) for one rotation of the eccentric rotor 21. The outputs of the coils C ₂ , C ₄ , C ₆ , C ₈ , C ₁₀ , C ₁₂ , C ₁₄ , C ₁₆ , C ₁₈ , C ₂₀ , C ₂₂ , C ₂₄ constituting the second coil group G ₂ are as follows: The signals are synthesized so as to be a signal having one cycle for one rotation of the eccentric rotor 21.

In the first embodiment, the coils C ₁ , C ₃ , C ₅ , C ₇ , C ₉ , C ₁₁ , C ₁₃ , C ₁₅ , C ₁₇ , C ₁₉ , C ₂₁ , C constituting the _first coil group G ₁ are used. ₂₃ and the coils C ₂ , C ₄ , C ₆ , C ₈ , C ₁₀ , C ₁₂ , C ₁₄ , C ₁₆ , C ₁₈ , C ₂₀ , C ₂₂ , C ₂₄ constituting the _second coil group G ₂ The eccentric rotors 21 are alternately arranged along a circumference on the same plane orthogonal to the rotation axis (rotation center O ₁ ) of the eccentric rotor 21. Thus, the first coil group G ₁ and the second coil group G ₂ have the same number of coils. The first coil group G ₁ and the second coil group G ₂ are provided along the same circumference orthogonal to the rotational axis of the eccentric rotor 21. In the first embodiment for convenience, and the arrangement angle to C ₂₄ coil C ₁ around the rotational center O _1, the arrangement angle of the coils C ₁ is provided 0 degrees and (360 degrees), the coils C _2, In the order of C ₃ ,..., C ₂₄ , 15 degrees, 30 degrees,. In the first embodiment, for example, the case where the positional relationship between the coils C ₁ , C ₂ ,..., C ₂₄ and the eccentric rotor 21 shown in FIG. However, the method of determining the origin of the rotation angle of the eccentric rotor 21 is arbitrary.

Figure 3 is a schematic diagram showing a first example of wiring coil group G _1. The first coil group G ₁ has a wiring in which four phases including a first phase P ₁ , a second phase P ₂ , a third phase P ₃ and a fourth phase P ₄ are connected in parallel. Each of the four phases is provided with three coils connected in series. In the first embodiment, the three coils provided in each of the four phases are arranged at intervals of 120 degrees around the rotation center O ₁ . Further, the first phase P ₁ and the second phase P ₂ have a phase difference of 60 degrees around the rotation center O ₁ . Further, the third phase P ₃ and the fourth phase P ₄ have a phase difference of 60 degrees around the rotation center O ₁ . Further, the first phase P ₁ and the third phase P ₃ have a phase difference of 90 degrees around the rotation center O ₁ .

More specifically, the first coil group G ₁ includes, for example, a first phase P ₁ connected in series in the order of coils C ₁ , C ₉ , and C ₁₇ from one end side to the other end side, and one end The second phase P ₂ connected in series in the order of the coils C ₁₃ , C ₂₁ , C ₅ from the side to the other end side, and the coils C ₇ , C ₁₅ , C _{23 in} the order from the one end side to the other end side and a third phase P ₃ are connected in series, and a fourth phase P ₄ that are connected in series in the order of coil C _19, C _3, C ₁₁ from one end to the other end. The connection order of the three coils in each phase can be changed as appropriate.

On one side of the first four phases have coil group G _1, the common terminal COM1 is provided. The first phase P ₁ , the second phase P ₂ , the third phase P ₃ , and the fourth phase P ₄ generate different current signals according to the excitation signal from the common terminal COM1. Specifically, the first phase P ₁ generates a signal that functions as a sin θ component. The second phase P ₂ generates a signal that functions as a (−sin θ) component. The third phase P ₃ generates a signal that functions as a cos θ component. Further, the fourth phase P ₄ generates a signal that functions as a (−cos θ) component. The current signals of each of the four phases of the first coil group G ₁ are individually converted into voltage signals by a current / voltage converter 41a having a detection resistor R provided at the other end of each of the four phases. Is done.

Hereinafter, the first phase P ₁ signal converted into the voltage signal is referred to as a first sin θ signal. Further, the second phase P ₂ signal converted into the voltage signal is defined as a first (−sin θ) signal. Further, the signal of the third phase P ₃ converted into the voltage signal is set as the first cos θ signal. Further, the signal of the fourth phase P ₄ converted into the voltage signal is defined as a first (−cos θ) signal. That is, the first coil group G ₁ has a plurality of coils to output a first electrical signal (first 1sinθ signal) and the first phase P ₁ connected in series, the first phase P ₁ across the rotational axis A second phase P ₂ in which a plurality of coils that are provided on the opposite side and output a second electrical signal (first (−sin θ) signal) are connected in series, and first phases P ₁ and 90 around the rotation axis. A third phase P ₃ in which a plurality of coils that are provided so as to be in a positional relationship and output a third electrical signal (first cos θ signal) are connected in series, and the opposite of the first phase P ₁ across the rotating shaft And a fourth phase P ₄ connected in series with a plurality of coils provided on the side and outputting a fourth electric signal (first (−cos θ) signal).

The first sin θ signal and the first (−sin θ) signal are input to the first differential amplifier circuit A ₁ . In the first embodiment, the non-inverting input (+) of the first differential amplifier circuit A ₁ is the first sin θ signal. In the first embodiment, the inverting input (−) of the first differential amplifier circuit A ₁ is the first (−sin θ) signal.

The input / output of the first differential amplifier circuit A ₁ will be described with reference to the graphs of FIGS. 4 to 6 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₁ , C ₉ , and C ₁₇ provided in the first phase P ₁ . FIG. 7 is a graph illustrating an example of a voltage waveform of the first sin θ signal. 8 to 10 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₁₃ , C ₂₁ , and C ₅ provided in the second phase P ₂ . FIG. 11 is a graph illustrating an example of a voltage waveform of the first (−sin θ) signal. Figure 12 is a graph showing an example of a first output voltage waveform of the differential amplifier circuit A _1. The angle of the horizontal axis shown in FIGS. 4 to 12 indicates the rotation angle of the eccentric rotor 21.

The voltages of the current signals output from the three coils C ₁ , C ₉ , C ₁₇ provided in the first phase P ₁ according to the excitation signal and the rotation angle of the eccentric rotor 21 are, for example, FIG. 4, FIG. As shown in FIG. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₁ , C ₉ , and C ₁₇ shown in FIGS. 4, 5, and 6 increase most are 270 degrees, 150 degrees, and 30 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the first sin θ signal obtained by converting the current signals of the three coils C ₁ , C ₉ , C ₁₇ combined in series in the first phase P ₁ into voltage signals is obtained from the eccentric rotor 21. According to the rotation angle, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 7 is relatively large when the rotation angle of the eccentric rotor 21 is 30 degrees, 150 degrees, and 270 degrees, and the voltage amplitude decreases as the distance from these angles increases. The voltage of the current signal output from the three coils C ₁₃ , C ₂₁ , C ₅ provided in the second phase P ₂ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 8, FIG. 10 is different. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₁₃ , C ₂₁ , and C ₅ shown in FIGS. 8, 9, and 10 increase most are 90 degrees, 330 degrees, and 210 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the first (−sin θ) signal obtained by converting the current signals of the three coils C ₁₃ , C ₂₁ , and C ₅ combined in series in the second phase P ₂ into voltage signals is: Depending on the rotation angle of the eccentric rotor 21, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 11 is relatively large when the rotation angle of the eccentric rotor 21 is 90 degrees, 210 degrees, and 330 degrees, and the amplitude of the voltage decreases as the distance from these angles increases.

When the voltage waveform shown in FIG. 7 and the waveform obtained by inverting the voltage waveform shown in FIG. 11 are synthesized, the waveform shown in FIG. 12 is obtained. That is, the first differential amplifier circuit A ₁ combines the first sin θ signal and the inverted first (−sin θ) signal, and outputs a signal having a voltage waveform as shown in FIG. The waveform shown in FIG. 12 repeats the increase and decrease of positive and negative amplitudes at a cycle of 2n times with respect to one rotation of the eccentric rotor 21. The amplitude of the voltage shown in FIG. 12 is relatively large when the rotation angle of the eccentric rotor 21 is 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 degrees, and 330 degrees. Further, the amplitude of the voltage shown in FIG. 12 is relatively small when the rotation angle of the eccentric rotor 21 is 0 degrees (360 degrees), 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees. Zero crossing. This indicates that the output voltage waveform of the first differential amplifier circuit A ₁ functions as a signal having a period of n times (for example, n = 3) with respect to one rotation of the eccentric rotor 21.

Specifically, the waveform W ₁ that traces the peak voltage in the amplitude of the voltage waveform shown in FIG. 12 is a waveform that repeats positive and negative increases and attenuations with a period of 2n times with respect to one rotation of the eccentric rotor 21. Here, when the polarity (positive or negative) of the voltage to be traced is switched at the timing when the positive and negative amplitudes are most attenuated according to the change in the rotation angle of the eccentric rotor 21 (for example, the zero cross point), the peak voltage is switched. The waveform obtained by tracing (for example, the waveform L ₁ ) is a sine wave having a period n times as large as one rotation of the eccentric rotor 21.

In the example shown in FIG. 12, a waveform W ₁ including two waveforms L ₁ and LT ₁ obtained by switching the polarity of a voltage to be traced at the zero cross point and tracing the peak voltage is illustrated. In the first embodiment, the waveform L ₁ is employed as a sine wave having a period n times as large as one rotation of the eccentric rotor 21.

The first cos θ signal and the first (−cos θ) signal are input to the second differential amplifier circuit A ₂ . In the first embodiment, the non-inverting input (+) of the second differential amplifier circuit A ₂ is the first cos θ signal. In the first embodiment, the inverting input (−) of the second differential amplifier circuit A ₂ is the first (−cos θ) signal.

The input / output of the second differential amplifier circuit A ₂ will be described with reference to the graphs of FIGS. 13 to 15 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₇ , C ₁₅ , and C ₂₃ provided in the third phase P ₃ . FIG. 16 is a graph illustrating an example of a voltage waveform of the first cos θ signal. FIGS. 17 to 19 are graphs showing examples of voltage waveforms indicated by current signals of the _three coils C ₁₉ , C ₃ , and C ₁₁ provided in the fourth phase P ₄ . FIG. 20 is a graph illustrating an example of a voltage waveform of the first (−cos θ) signal. Figure 21 is a graph showing an example of a second output voltage waveform of the differential amplifier circuit A _2. The angle of the horizontal axis shown in FIGS. 13 to 21 indicates the rotation angle of the eccentric rotor 21.

The voltage of the current signal output from the three coils C ₇ , C ₁₅ , C ₂₃ provided in the third phase P ₃ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 13, FIG. As shown in FIG. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₇ , C ₁₅ , and C ₂₃ shown in FIGS. 13, 14, and 15 increase most are 180 degrees, 60 degrees, and 300 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the first cos θ signal obtained by converting the current signals of the three coils C ₇ , C ₁₅ , and C ₂₃ combined in series in the third phase P ₃ into voltage signals is obtained from the eccentric rotor 21. Depending on the rotation angle, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 16 is relatively large when the rotation angle of the eccentric rotor 21 is 60 degrees, 180 degrees, and 300 degrees, and the amplitude of the voltage decreases as the distance from these angles increases. The voltage of the current signal output from the _three coils C ₁₉ , C ₃ , C ₁₁ provided in the fourth phase P ₄ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 17, FIG. 19 are different. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₁₉ , C ₃ , and C ₁₁ shown in FIGS. 17, 18, and 19 increase most are 0 degrees (360 degrees), 240 degrees, and 120 degrees, respectively. The amplitude of each voltage decreases as the distance from the angle increases. The voltage waveform of the first (−cos θ) signal obtained by converting the current signals of the _three coils C ₁₉ , C ₃ , and C ₁₁ combined in series in the fourth phase P ₄ into voltage signals is: Depending on the rotation angle of the eccentric rotor 21, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 20 is relatively large when the rotation angle of the eccentric rotor 21 is 0 degrees (360 degrees), 120 degrees, and 240 degrees, and the amplitude of the voltage is attenuated as the distance from these angles increases. doing.

When the voltage waveform shown in FIG. 16 and the waveform obtained by inverting the voltage waveform shown in FIG. 20 are combined, the waveform shown in FIG. 21 is obtained. That is, the second differential amplifier circuit A ₂ combines the first cos θ signal and the inverted first (−cos θ) signal, and outputs a signal having a voltage waveform as shown in FIG. The waveform shown in FIG. 21 repeats the increase and decrease of positive and negative amplitudes with a period of 2n times with respect to one rotation of the eccentric rotor 21. The amplitude of the voltage shown in FIG. 21 is relatively large when the rotation angle of the eccentric rotor 21 is 0 degrees (360 degrees), 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 300 degrees. In addition, the amplitude of the voltage shown in FIG. 21 is relatively small when the rotation angle of the eccentric rotor 21 is 30 degrees, 90 degrees, 150 degrees, 210 degrees, 270 degrees, and 330 degrees, resulting in zero crossing. Yes. This indicates that the output voltage waveform of the second differential amplifier circuit A ₂ functions as a signal having a cycle of n times (for example, n = 3) with respect to one rotation of the eccentric rotor 21.

Specifically, the waveform W ₂ that traces the peak voltage in the amplitude of the voltage waveform shown in FIG. 21 is a waveform that repeats positive and negative increases and attenuations with a period of 2n times with respect to one rotation of the eccentric rotor 21. Here, when the polarity (positive or negative) of the voltage to be traced is switched at the timing when the positive and negative amplitudes are most attenuated according to the change in the rotation angle of the eccentric rotor 21 (for example, the zero cross point), the peak voltage is switched. The waveform (for example, waveform L ₂ ) obtained by tracing is a cosine wave having a period n times as large as one rotation of the eccentric rotor 21.

In the example shown in FIG. 21, a waveform W ₂ including _two waveforms L ₂ and LT ₂ obtained by switching the polarity of the voltage to be traced at the zero cross point and tracing the peak voltage is illustrated. In the first embodiment, the waveform L ₂ is adopted as a cosine wave having a period n times as large as one rotation of the eccentric rotor 21.

Since the first phase P ₁ and the third phase P ₃ have a phase difference of 90 degrees around the rotation center O ₁ , one functions as a sinn θ signal corresponding to a sine wave, and the other corresponds to a cosine wave. Functions as a cosnθ signal. In the case of the first embodiment (n = 3), the output of the first differential amplifier circuit A ₁ functions as a sin 3θ signal, and the output of the second differential amplifier circuit A ₂ functions as a cos 3θ signal.

Thus, 2-phase signal converter 42a having a first differential amplifier circuit A ₁ and the second differential amplifier circuit A ₂ is eccentric rotor 21 on the basis of the first electrical signal output from the coil group G ₁ Functions as a multi-period signal output unit that outputs a signal of a plurality of periods for one period of one rotation. The multi-cycle signal output unit (two-phase signal converter 42a) inverts one of the two electric signals of the first phase P ₁ and the second phase P ₂ to generate the two electric signals. The signals are combined, and one of the two electric signals of the third phase P ₃ and the fourth phase P ₄ is inverted to synthesize the two electric signals.

Figure 22 is a schematic diagram showing a second example of wiring coil group G _2. The second coil group G ₂ has a wiring in which four phases including a fifth phase P ₅ , a sixth phase P ₆ , a seventh phase P ₇ and an eighth phase P ₈ are connected in parallel. Each of the four phases is provided with three coils connected in series. In the first embodiment, the three coils provided in each of the four phases are arranged at intervals of 30 degrees around the rotation center O ₁ . Further, the fifth phase P ₅ and the sixth phase P ₆ are in a positional relationship facing each other across the rotation center O ₁ , and have a phase difference of 180 degrees. Further, the seventh phase P ₇ and the eighth phase P ₈ are in a positional relationship facing each other across the rotation center O ₁ , and have a phase difference of 180 degrees. Further, the fifth phase P ₅ and the seventh phase P ₇ have a phase difference of 90 degrees around the rotation center O ₁ .

More specifically, the second coil group G ₂ includes, for example, a fifth phase P ₅ connected in series in the order of coils C ₂ , C ₄ , C ₆ from one end side to the other end side, and one end The sixth phase P ₆ connected in series in the order of the coils C ₁₄ , C ₁₆ , C ₁₈ from the side to the other end side, and the coils C ₈ , C ₁₀ , C _{12 in} the order from the one end side to the other end side. A seventh phase P ₇ connected in series and an eighth phase P ₈ connected in series in the order of coils C ₂₀ , C ₂₂ , C ₂₄ from one end side to the other end side are included. The connection order of the three coils in each phase can be changed as appropriate.

On one side of the second four phases having coil groups G _2, the common terminal COM2 is provided. The fifth phase P ₅ , the sixth phase P ₆ , the seventh phase P ₇ , and the eighth phase P ₈ generate different current signals according to the excitation signal from the common terminal COM2. Specifically, the fifth phase P ₅ generates a signal that functions as a sin θ component. The sixth phase P ₆ generates a signal that functions as a (−sin θ) component. The seventh phase P ₇ generates a signal that functions as a cos θ component. In addition, the eighth phase P ₈ generates a signal that functions as a (−cos θ) component. Each of the current signals of four phases with the second coil group G ₂ is converted into individual voltage signal by a current / voltage converter 41b having a detection resistor R provided at the other end of each of the four phases Is done.

Hereinafter, the signal of the fifth phase P ₅ converted into the voltage signal is referred to as a second sin θ signal. Further, the signal of the sixth phase P ₆ converted into the voltage signal is defined as a second (−sin θ) signal. Further, the signal of the seventh phase P ₇ converted into the voltage signal is set as the second cos θ signal. Further, the signal of the eighth phase P ₈ converted into the voltage signal is set as a second (−cos θ) signal.

The second sin θ signal and the second (−sin θ) signal are input to the third differential amplifier circuit A ₃ . In the first embodiment, the non-inverting input (+) of the third differential amplifier circuit A ₃ is the second sin θ signal. In the first embodiment, the inverting input (−) of the third differential amplifier circuit A ₃ is the second (−sin θ) signal.

The input / output of the third differential amplifier circuit A ₃ will be described with reference to the graphs of FIGS. 23 to 25 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₂ , C ₄ , and C ₆ provided in the fifth phase P ₅ . FIG. 26 is a graph illustrating an example of a voltage waveform of the second sin θ signal. 27 to 29 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₁₄ , C ₁₆ , and C ₁₈ provided in the sixth phase P ₆ . FIG. 30 is a graph illustrating an example of a voltage waveform of the second (−sin θ) signal. Figure 31 is a graph showing an example of the third output voltage waveform of the differential amplifier circuit A _3. The angle of the horizontal axis shown in FIGS. 23 to 31 indicates the rotation angle of the eccentric rotor 21.

The voltage of the current signal output from the three coils C ₂ , C ₄ , C ₆ provided in the fifth phase P ₅ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 23, FIG. 24, FIG. As shown in FIG. The rotational angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₂ , C ₄ , and C ₆ shown in FIGS. 23, 24, and 25 increase the most are 255 degrees, 225 degrees, and 195 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the second sin θ signal obtained by converting the current signals of the three coils C ₂ , C ₄ , and C ₆ combined in series in the fifth phase P ₅ into voltage signals is obtained from the eccentric rotor 21. According to the rotation angle, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 26 is relatively large when the rotation angle of the eccentric rotor 21 is 225 degrees, and the amplitude of the voltage decreases as the distance from the angle increases. The voltage of the current signal output from the three coils C ₁₄ , C ₁₆ , C ₁₈ provided in the sixth phase P ₆ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 27, FIG. 28, FIG. 29 are different. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₁₄ , C ₁₆ , and C ₁₈ shown in FIGS. 27, 28, and 29 are maximized are 75 degrees, 45 degrees, and 15 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the second (−sin θ) signal obtained by converting the current signals of the three coils C ₁₄ , C ₁₆ , C ₁₈ synthesized in series in the sixth phase P ₆ into voltage signals is: Depending on the rotation angle of the eccentric rotor 21, for example, as shown in FIG. The amplitude of the voltage shown in FIG. 30 is relatively large when the rotation angle of the eccentric rotor 21 is 45 degrees, and the amplitude of the voltage decreases as the distance from the angle increases.

When the voltage waveform shown in FIG. 26 and the waveform obtained by inverting the voltage waveform shown in FIG. 30 are synthesized, the waveform shown in FIG. 31 is obtained. That is, the third differential amplifier circuit A ₃ synthesizes the second sin θ signal and the inverted second (−sin θ) signal, and outputs a signal having a voltage waveform as shown in FIG. The waveform shown in FIG. 31 repeats increase and decrease of positive and negative amplitudes at a period twice as large as one rotation of the eccentric rotor 21. The amplitude of the voltage shown in FIG. 31 is relatively large when the rotation angle of the eccentric rotor 21 is 45 degrees and 225 degrees. Further, the amplitude of the voltage shown in FIG. 31 is zero-crossed because the amplitude is relatively small when the rotation angle of the eccentric rotor 21 is 135 degrees and 315 degrees. This indicates that the output voltage waveform of the third differential amplifier circuit A ₃ functions as a signal having one cycle for one rotation of the eccentric rotor 21.

A waveform W ₃ that traces the peak voltage in the amplitude of the voltage waveform shown in FIG. 31 is a waveform that repeats positive and negative increases and attenuations at a cycle twice that of one rotation of the eccentric rotor 21. Here, when the polarity (positive or negative) of the voltage to be traced is switched at the timing when the positive and negative amplitudes are most attenuated according to the change in the rotation angle of the eccentric rotor 21 (for example, the zero cross point), the peak voltage is switched. The waveform obtained by tracing (for example, waveform L ₃ ) draws a sine curve having one cycle for one rotation of the eccentric rotor 21.

In the example shown in FIG. 31, a waveform W ₃ including two waveforms L ₃ and LT ₃ obtained by switching the polarity of the voltage to be traced at the zero cross point and tracing the peak voltage is illustrated. In the first embodiment, the waveform L ₃ is adopted as a sine curve having one cycle for one rotation of the eccentric rotor 21.

The second cos θ signal and the second (−cos θ) signal are input to the fourth differential amplifier circuit A ₄ . In the first embodiment, the non-inverting input (+) of the fourth differential amplifier circuit A ₄ is the second cos θ signal. In the first embodiment, the inverting input (−) of the fourth differential amplifier circuit A ₄ is the second (−cos θ) signal.

The input / output of the fourth differential amplifier circuit A ₄ will be described with reference to the graphs of FIGS. 32 to 34 are graphs showing examples of voltage waveforms indicated by current signals of the three coils C ₈ , C ₁₀ , and C ₁₂ provided in the seventh phase P ₇ . FIG. 35 is a graph illustrating an example of a voltage waveform of the second cos θ signal. 36 to 38 are graphs showing examples of voltage waveforms indicated by the current signals of the three coils C ₂₀ , C ₂₂ , and C ₂₄ provided in the eighth phase P ₈ . FIG. 39 is a graph illustrating an example of a voltage waveform of the second (−cos θ) signal. Figure 40 is a graph showing an example of a fourth output voltage waveform of the differential amplifier circuit A _4. The angle of the horizontal axis shown in FIGS. 32 to 40 indicates the rotation angle of the eccentric rotor 21.

The voltage of the current signal output from the three coils C ₈ , C ₁₀ , C ₁₂ provided in the seventh phase P ₇ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 32, FIG. 33, FIG. 34 are different. The rotational angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₈ , C ₁₀ , and C ₁₂ shown in FIGS. 32, 33, and 34 increase the most are 165 degrees, 135 degrees, and 105 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the second cos θ signal obtained by converting the current signals of the three coils C ₈ , C ₁₀ , and C ₁₂ connected in series in the seventh phase P ₇ into a voltage signal is obtained from the eccentric rotor 21. For example, as shown in FIG. 35 according to the rotation angle. The amplitude of the voltage shown in FIG. 35 is relatively large when the rotation angle of the eccentric rotor 21 is 135 degrees, and the amplitude of the voltage decreases as the distance from the angle increases. The voltage of the current signal output from the three coils C ₂₀ , C ₂₂ , C ₂₄ provided in the eighth phase P ₈ according to the excitation signal and the rotation angle of the eccentric rotor 21 is, for example, FIG. 36, FIG. 37, FIG. As shown in FIG. The rotation angles of the eccentric rotor 21 in which the amplitudes of the voltages of the coils C ₂₀ , C ₂₂ , and C ₂₄ shown in FIGS. 36, 37, and 38 increase most are 345 degrees, 315 degrees, and 285 degrees, respectively. As the distance increases, the amplitude of each voltage decreases. The voltage waveform of the second (−cos θ) signal obtained by converting the current signals of the three coils C ₂₀ , C ₂₂ , C ₂₄ combined in series in the eighth phase P ₈ into voltage signals is: For example, as shown in FIG. 39 according to the rotation angle of the eccentric rotor 21. The amplitude of the voltage shown in FIG. 39 is relatively large when the rotation angle of the eccentric rotor 21 is 315 degrees, and the amplitude of the voltage decreases as the distance from the angle increases.

When the voltage waveform shown in FIG. 35 and the waveform obtained by inverting the voltage waveform shown in FIG. 39 are synthesized, the waveform shown in FIG. 40 is obtained. That is, the fourth differential amplifier circuit A ₄ synthesizes the second cos θ signal and the inverted second (−cos θ) signal, and outputs a signal having a voltage waveform as shown in FIG. The waveform shown in FIG. 40 repeats increase and decrease in positive and negative amplitudes at a period twice that of one rotation of the eccentric rotor 21. The amplitude of the voltage shown in FIG. 40 is relatively large when the rotation angle of the eccentric rotor 21 is 135 degrees and 315 degrees. In addition, the amplitude of the voltage shown in FIG. 40 is zero-crossed because the amplitude is relatively small when the rotation angle of the eccentric rotor 21 is 45 degrees and 225 degrees. This indicates that the output voltage waveform of the fourth differential amplifier circuit A ₄ functions as a signal having one cycle for one rotation of the eccentric rotor 21.

A waveform W ₄ that traces the peak voltage in the amplitude of the voltage waveform shown in FIG. 40 is a waveform that repeats positive and negative increases and attenuations at a period twice that of one rotation of the eccentric rotor 21. Here, when the polarity (positive or negative) of the voltage to be traced is switched at the timing when the positive and negative amplitudes are most attenuated according to the change in the rotation angle of the eccentric rotor 21 (for example, the zero cross point), the peak voltage is switched. The waveform obtained by tracing (for example, waveform L ₄ ) draws a sine curve having one cycle for one rotation of the eccentric rotor 21.

In the example shown in FIG. 40, a waveform W ₄ including two waveforms L ₄ and LT ₄ obtained by switching the polarity of the voltage to be traced at the zero cross point and tracing the peak voltage is illustrated. In the first embodiment, the waveform L ₄ is adopted as a sine curve having one cycle for one rotation of the eccentric rotor 21.

Since the fifth phase P ₅ and the seventh phase P ₇ have a phase difference of 90 degrees around the rotation center O ₁ , one functions as a sin θ signal and the other functions as a cos θ signal. In the first embodiment, the output of the third differential amplifier circuit A ₃ functions as a sin θ signal, and the output of the fourth differential amplifier circuit A ₄ functions as a cos θ signal.

As described above, the two-phase signal converter 42b having the third differential amplifier circuit A ₃ and the fourth differential amplifier circuit A ₄ has the eccentric rotor 21 based on the electric signal output from the second coil group G _2. Functions as a one-cycle signal output unit that outputs a signal of one cycle for one cycle of rotation. The one-cycle signal output unit (two-phase signal converter 42b) inverts one of the two electric signals of the fifth phase P ₅ and the sixth phase P ₆ to generate the two electric signals. The signals are combined, and one of the two electric signals of the seventh phase P ₇ and the eighth phase P ₈ is inverted to synthesize the two electric signals.

The output of the first coil group G ₁ output through the first differential amplifier circuit A ₁ and the second differential amplifier circuit A ₂ is a signal (INC signal) indicating a relative (INcremental) INC rotation angle. Function. The output of the second coil group G ₂ output via the third differential amplifier circuit A ₃ and the fourth differential amplifier circuit A ₄ is a signal (ABS signal) indicating an absolute (ABS) rotation angle. Function. The INC signal and the ABS signal may be used in combination. For example, the absolute rotation angle indicated by the ABS signal may be corrected by the rotation angle within the range of 360 degrees / n indicated by the INC signal. Specifically, the absolute rotation angle is obtained from the ABS signal. Further, the relative rotation angle is obtained from the INC signal. At this time, the rotation angle of the eccentric rotor 21 that can be specified from the INC signal is a rotation angle within the range of 360 degrees / n, but the rotation angle within the range of 360 degrees / n including the absolute rotation angle obtained from the ABS signal. By obtaining the relative rotation angle in the range, the rotation angle of the eccentric rotor 21 can be obtained from the INC signal. If the obtained absolute rotation angle and relative rotation angle match, no correction is necessary. On the other hand, when the obtained absolute rotation angle and the relative rotation angle do not coincide with each other, the absolute rotation angle is corrected by the rotation angle of the eccentric rotor 21 obtained from the INC signal, and the corrected rotation angle is detected. The rotation angle of

As described above, according to the first embodiment, the eccentric rotor 21 rotates once based on the electrical signal a plurality periodic signal output unit (2-phase signal converter 42a) is outputted from the first coil group G ₁ Since a signal having a plurality of cycles is output for one cycle, a signal having a plurality of cycles can be obtained from one cycle in which the eccentric rotor 21 rotates once. Also, one period signal output section (the two-phase signal converter 42b) the first eccentric rotor 21 based on the electric signal output from the coil group G ₁ is output one cycle of the signal to one period of rotation 1 Therefore, a signal of one cycle to one cycle in which the eccentric rotor 21 rotates once can be obtained. Further, since the first coil group G ₁ and the second coil group G ₂ are provided along the same circumference orthogonal to the rotation axis of the eccentric rotor 21, the first coil group G ₁ and the second coil group G ₂ are arranged in the first radial direction around the rotation axis. The coil group G ₁ and the second coil group G ₂ can be combined more compactly.

In addition, _one of the two electrical signals of the first phase P ₁ and the second phase P ₂ is inverted to synthesize the two electrical signals, and the third phase P ₃ electrical signal and the second phase P ₃ electrical signal are combined. By inverting one of the two electric signals of the four-phase P ₄ electric signals and synthesizing the two electric signals, it is possible to more reliably detect a change in the electric signal according to the rotation angle of the eccentric rotor 21. Output can be obtained. In addition, even if a noise component is included in the electrical signal output from the coil, the influence of this noise component can be suppressed by inverting and synthesizing one of the signals in the oppositely arranged phase. it can. For the fifth phase P ₅ , the sixth phase P ₆ , the seventh phase P ₇ and the eighth phase P ₈ , the first phase P ₁ , the second phase P ₂ , the third phase P ₃ and the fourth phase P ₄ Similar effects can be obtained. In addition, by providing a plurality of coils in each phase, it is possible to extract second-order or higher-order components included in the electrical signal output from the coils according to the rotation of the eccentric rotor 21.

In particular, when n = 3 as exemplified in the description of the first embodiment, the detection resolution based on the output from the _first coil group G ₁ obtained based on the eccentric component due to one rotation of the eccentric rotor 21. Can be tripled. Furthermore, as illustrated in the description of the first embodiment, n = 3, and three coils provided in each of the four phases of the first coil group G ₁ are arranged at intervals of 120 degrees. In this case, the third order component can be extracted by synthesizing the current signals from these three coils.

The first coil group G ₁ and the second coil group G ₂ are alternately arranged along a circumference on the same plane orthogonal to the rotation axis, so that the first coil group G ₁ and the second coil group G ₂ are arranged in the direction along the rotation axis. The coil group G ₁ and the second coil group G ₂ can be combined more compactly. Further, the arrangement of the coils can be made uniform in an annular shape around the rotation axis.

  Furthermore, the rotational angle of the eccentric rotor 21 can be obtained with higher accuracy by correcting the absolute rotational angle indicated by the ABS signal with the rotational angle within the range of 360 degrees / n indicated by the INC signal.

(Embodiment 2)
Next, Embodiment 2 of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 41 is a cross-sectional view of a direct drive (DD) motor 10 according to the second embodiment. As shown in FIG. 41, in the DD motor 10, the rotary shaft 12 is rotatably supported via a bearing 13 fixed to the outer peripheral side surface of a hollow cylindrical inner housing 11. The rotary shaft 12 is configured as a hollow cylindrical body so that the inner housing 11 can be overlaid therein.

  As for the rotating shaft 12, the thickness of the cylinder wall is undulating along the rotating shaft direction. The rotating shaft 12 defines an indoor space 1 for accommodating the resolver 20 in a gap with the inner housing 11 and an indoor space 2 for accommodating the motor unit 16. These indoor spaces 1 and 2 are separated by a bearing 13 and are separated by a certain distance so that the leakage magnetic flux from the motor unit 16 does not reach the indoor space 1. When the bearing 13 or the like is not interposed between the indoor spaces 1 and 2 and both are close to each other, it is desirable to provide a shielding member so that the leakage magnetic flux from the motor unit 16 does not reach the indoor space 1.

  The motor unit 16 is an outer rotor type PM (Permanent Magnet) motor including a rotor 14 and a stator 15. The rotor 14 is made of a permanent magnet having N poles and S poles fixed alternately along the circumferential direction on the inner wall of the rotating shaft 12. The stator 15 is a motor core formed by laminating a plurality of thin iron plates, and the rotor 14 is provided with an air gap for preventing the rotor 14 from sliding on the stator 15 as the rotor 14 rotates. Are fixed to the outer wall of the inner housing 11 so as to face each other. Here, an outer rotor type PM motor is illustrated as the motor unit 16, but an inner rotor type PM motor may be employed. Various motors other than the PM motor can be employed as the motor unit 16. For example, the rotor 14 may be formed by laminating thin iron plates instead of permanent magnets, and may have a predetermined number of internal teeth or external teeth.

The eccentric rotor 21 of the resolver 20 is connected to the bolt receiver 18 and is fixed to the inner peripheral surface of the rotating shaft 12 by a bolt 18a. The stator 22 of the resolver 20 is connected to the bolt receiver 19 and is fixed to the outer peripheral wall of the inner housing 11 by a bolt 19 a so as to face the eccentric rotor 21. In FIG. 41, a coil C that can be any one of the coils C _{1 to} C ₂₄ is denoted by reference symbol C.

  The inner housing 11 and the rotating shaft 12 that define the indoor space 1 are preferably non-magnetic. Since these members that define the indoor space 1 are non-magnetic, the leakage magnetic flux from the motor unit 16 can be configured not to reach the indoor space 1.

  As described above, according to the second embodiment, it is possible to provide the DD motor 10 that can obtain the effect produced by the resolver 20 of the first embodiment.

  Further, the DD motor 10 can immediately detect the rotation angle of the output shaft immediately after the power is turned on by the resolver 20 including the two-phase signal converter 42b that functions as an output for detecting the absolute rotation angle.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. The same components as those in the first embodiment and the second embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 42 is a block configuration diagram including a DD motor system with a driver unit according to the third embodiment. The DD motor system with a driver unit includes a DD motor 10, a resolver 20 incorporated in the DD motor 10, and a part of a drive unit 60 that controls them. The drive unit 60 takes in an output signal (resolver signal) obtained by supplying an excitation signal to either the first coil group G ₁ or the second coil group G ₂ of the resolver 20 and outputs a digital angle signal φ. And a CPU 61 that generates a rotation angle position signal from the digital angle signal φ and operates the DD motor 10 with power supplied from the power amplifier 62. The drive unit 60 and the resolver 20 are connected by a resolver cable 71, and the drive unit 60 and the motor unit 16 are connected by a motor cable 72. The common terminals COM1 and COM2, the current / voltage converters 41a and 41b, and the two-phase signal converters 42a and 42b included in the detection circuit unit 40 illustrated in FIG. 42 are the same as the circuit unit 30 of the first embodiment illustrated in FIG. It is the same as the structure which has. Further, each INCsin signal and INCcos signal 2-phase signal converter 42a is outputted in the third embodiment, the output (Sinnshita signal) of the first differential amplifier circuit A ₁ in the first embodiment and the second differential amplifier circuit This is the output of A ₂ (cosnθ signal). Further, each ABSsin signal and ABScos signal 2-phase signal converter 42b is outputted in the third embodiment, the output (sin [theta signal) of the third differential amplifier circuit A ₃ in the first embodiment and the fourth differential amplifier circuit This is an output of A ₄ (cos θ signal).

  The servo driver 50 amplifies the excitation signal output from the transmitter 51 to an appropriate signal level by the amplifier 52, and supplies the excitation signal to either the common terminal COM1 or the common terminal COM2 via the changeover switch 53. The excitation signal is supplied by switching the path. The changeover switch 53 is a switching means that is arranged on the excitation signal supply path from the transmitter 51 to the common terminal COM1 and the common terminal COM2, and switches the supply target of the excitation signal. The connection switching of the selector switch 53 to the common terminals COM1 and COM2 is controlled by a switch switching signal output from the CPU 61.

Immediately after power is turned the system was started, CPU 61 is by switching connecting the switch 53 to the common terminal COM2, and supplies an excitation signal to the second coil group G _2. Current signal outputted from the second coil group G ₂ is converted two-phase signals (sin [theta signal, cos [theta] signal) constituting the ABS signal through a current / voltage converter 41b and the two-phase signal converter 42b into an analog It is supplied to the switch 43.

After obtaining the ABS signal, CPU 61, by switching connecting the switch 53 to the common terminal COM1, and supplies an excitation signal to the first coil group G _1. Current signal output from the first coil group G ₁ is converted two-phase signals (Sinnshita signal, Cosnshita signal) constituting the INC signal through a current / voltage converter 41a and the two-phase signal converter 42a into an analog It is supplied to the switch 43.

  The analog switch 43 is a switching element that is controlled to be switched by an ABS / INC switching signal from the CPU 61. The analog switch 43 selectively passes either a two-phase ABS signal or a two-phase INC signal to receive an RDC (resolver digital signal). Converter) 44. The timing at which the signal passing through the analog switch 43 is switched from the two-phase ABS signal to the two-phase INC signal is synchronized with the timing at which the connection destination of the changeover switch 53 is switched from the common terminal COM1 to the common terminal COM2. An ABS / INC switching signal is output from the CPU 61 to the analog switch 43.

  The phase shifter 45 delays the phase of the excitation signal output from the transmitter 51 and supplies the RDC 44 with a Ref signal synchronized with the phase of the carrier signal of the two-phase signals constituting the ABS signal or INC signal. The RDC 44 digitizes the two-phase signal supplied from the analog switch 43 and outputs a digital angle signal φ to the CPU 61. The RDC 44 outputs an analog speed signal after synchronous rectification based on the oscillation angular frequency of the transmitter 51.

  In order to obtain the digital angle signal φ from the resolver signal, it is not always necessary to process it by hardware (3/2 phase converter, RDC, etc.). The resolver signal is A / D converted and processed by software. In this case, the digital angle signal φ may be obtained.

FIG. 43 is a flowchart describing the position detection processing routine of the CPU 61. With reference to FIG. 43, the above description will be described again with a focus on the control processing of the CPU 61. When the CPU 61 detects that the power is turned on when the system is stopped (step S1; No) (step S1; Yes), the CPU 61 outputs a switch change signal so as to connect the changeover switch 53 to the common terminal COM2 (step S2). Then, the excitation signal outputted from the oscillator 51 is supplied from the common terminal COM2 to the second coil group G _2, reluctance change corresponding to the rotational angular position is output to the detection circuit section 40 as a current signal. The detection circuit unit 40 converts this current signal into a voltage signal with the current / voltage converter 41 b, converts it into a two-phase signal with the two-phase signal converter 42 b, and supplies it to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase ABS signal as a signal to pass through the analog switch 43 (step S3).

  The two-phase ABS signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61. The CPU 61 acquires the rotation angle (abs) indicated by this digital signal (step S4).

Next, the CPU 61 outputs a switch change signal so as to connect the changeover switch 53 to the common terminal COM1 (step S5). Then, the excitation signal outputted from the oscillator 51 is supplied from the common terminal COM1 to the first coil group G _1, a reluctance change corresponding to the rotational angle position is supplied to the detection circuit section 40 as a current signal. The detection circuit unit 40 converts this current signal into a voltage signal with the current / voltage converter 41 a, converts it into a two-phase signal with the two-phase signal converter 42 a, and supplies it to the analog switch 43. The CPU 61 outputs an ABS / INC switching signal so as to select a two-phase INC signal as a signal that should pass through the analog switch 43 (step S6).

  The two-phase INC signal passes through the analog switch 43, is converted into a digital signal by the RDC 44, and is supplied to the CPU 61. The CPU 61 acquires the rotation angle (inc) indicated by this digital signal (step S7).

  The CPU 61 controls so that the changeover switch 53 remains connected to the common terminal COM1 until the power is turned off, while maintaining the signal passing through the analog switch 43 as a two-phase INC signal. (Step S8; No). When the CPU 61 detects that the power is turned off (step S8; Yes), the control routine ends.

(Modification)
FIG. 44 is a block diagram of a DD motor system with a driver unit, which is a modification of the third embodiment. The same configurations and functions as those of the third embodiment are denoted by the same reference numerals, and description thereof is omitted. If the current levels output from the first coil group G ₁ and the second coil group G ₂ are substantially the same, the current / voltage converter 41 sharing the current / voltage converters 41a and 41b, and 2 A two-phase signal converter 42 sharing the phase signal converters 42a and 42b is employed, and the analog switch 43 can be omitted. The sin signal and the cos signal output from the two-phase signal converter 42 are the ABSsin signal and the ABScos signal or the INCsin signal and the INCcos signal in the third embodiment.

The detection circuit unit 40a according to the modification has a configuration including an RDC 44 and a phase shifter 45 as in the third embodiment, in addition to the shared current / voltage converter 41 and the two-phase signal converter 42. Current signals output from the first coil group G ₁ and the second coil group G ₂ are converted into ABS signals or INC signals by the current / voltage converter 41, and further, two-phase signals are converted by the two-phase signal converter 42. Is converted to With this configuration, the current / voltage converter 41 and the two-phase signal converter 42 can be shared by the first coil group G ₁ and the second coil group G ₂ .

  As described above, according to the third embodiment and the modification, it is possible to provide a DD motor system that can obtain the effect achieved by the resolver 20 according to the first embodiment.

10 DD motor 14 Rotor 15 Stator 20 Resolver 21 Eccentric rotor 22 Stator 23 Stator pole 24 Coil bobbins 41, 41a, 41b Current / voltage converters 42, 42a, 42b Two-phase signal converter A ₁ First differential amplifier circuit A ₂ second differential amplifier circuit a ₃ third differential amplifier circuit a ₄ fourth differential amplifier circuits _{C 1, C 2, ...,} C 24 coils COM1, COM2 common terminal G ₁ first coil group G ₂ second Coil group P ₁ 1st phase P ₂ 2nd phase P ₃ 3rd phase P ₄ 4th phase P ₅ 5th phase P ₆ 6th phase P ₇ 7th phase P ₈ 8th phase

Claims (5)

A resolver stator used in combination with an eccentric rotor,
A first coil group having eight or more coils provided along the rotational direction of the eccentric rotor;
A multi-cycle signal output unit that outputs a signal of a plurality of cycles for one cycle in which the eccentric rotor makes one rotation based on an electrical signal output from the first coil group;
A second coil group having a plurality of coils provided separately from the eight or more coils and provided along the rotation direction of the eccentric rotor;
A one-cycle signal output unit that outputs a signal of one cycle with respect to the one cycle based on an electric signal output from the second coil group;
The resolver stator, wherein the first coil group and the second coil group are provided along a circumference on the same plane orthogonal to a rotation axis of the eccentric rotor. The first coil group includes:
A first phase in which a plurality of coils that output a first electrical signal are connected in series;
A second phase connected in series with a plurality of coils provided on the opposite side of the first phase across the rotating shaft and outputting a second electrical signal;
A third phase in which a plurality of coils that are provided so as to have a positional relationship of 90 degrees with the first phase around the rotation axis and that output a third electrical signal are connected in series;
A plurality of coils that are provided on the opposite side of the first phase across the rotating shaft and that output a fourth electrical signal are connected in series;
The multi-cycle signal output unit inverts one of the two electric signals of the first phase electric signal and the second phase electric signal to synthesize the two electric signals, and outputs the third phase electric signal. The resolver stator according to claim 1, wherein one of two electric signals of the signal and the fourth phase electric signal is inverted to synthesize the two electric signals. The resolver stator according to claim 1, wherein the first coil group and the second coil group have the same number of coils. The eccentric rotor;
Resolver stator according to any one of claims 1 to 3,
A resolver comprising: A resolver according to claim 4;
A direct drive motor having an output shaft to which the eccentric rotor is fixed;
A direct drive motor system comprising: a detection unit that detects a rotation angle of the output shaft based on a rotation angle indicated by the signal of the one cycle and a rotation angle indicated by the signal of the plurality of cycles.

Images