Variable reluctance angle detector

Abstract

[Problem] To provide a variable reluctance angle detector that produces a canceling effect when a rotor is eccentric, while suppressing a decrease in synthesized voltage when the rotor is not eccentric. [Solution] The variable reluctance angle detector includes: a rotor having a rotational harmonic of 1X; a stator provided with twelve teeth arranged circumferentially from a first tooth to a twelfth tooth; an excitation coil; a first output coil; and a second output coil. The excitation coil is wound in a forward direction with N1 turns around the first tooth and the seventh tooth, and in a reverse direction with N1 turns around the fourth tooth and the tenth tooth. The first output coil is wound in the forward direction around the first, second, and twelfth teeth, and in the reverse direction around the sixth, seventh, and eighth teeth. The second output coil is wound in the reverse direction around the third, fourth, and fifth teeth, and in the forward direction around the ninth, tenth, and eleventh teeth.

Description

Variable reluctance angle detector

[0001] The present disclosure relates to a variable reluctance angle detector in which a rotor having a shape in which gap permeance varies sinusoidally with respect to angle θ is rotatably mounted on a stator having excitation windings and output windings wound around its teeth.

[0002] In a variable reluctance angle detector (hereinafter referred to as a "resolver") with a shaft angle multiplier of 2X or 4X, the in-phase voltage coils are arranged at positions 180 degrees symmetrical about the center of the stator, and the rotors are also shaped 180 degrees symmetrical about the center of rotation. Therefore, when the center of rotation of the rotor is eccentric from the center of the stator, the gap between the coil and rotor narrows on one side in the eccentricity direction, increasing the output voltage, and the gap widens on the other side, decreasing the output voltage. If a canceling effect occurs, in which increases and decreases in the output voltage cancel each other out, the composite voltage does not increase or decrease significantly even if the rotor is eccentric.

[0003] However, in a resolver with a shaft angle multiplier of 1X, the rotor shape is not 180 degrees symmetrical about the center of rotation, so the cancellation effect does not occur. Therefore, if the rotor becomes eccentric, the output voltage changes significantly, reducing the detection accuracy of the rotation angle.

[0004] In Patent Document 1, in a resolver with a shaft angle multiplier of 1X and 12 slots, as shown in FIG. 3, the excitation winding 7, the SIN output winding 8, and the COS output winding 9 are selectively wound around tooth portions 1 to 12, so that the SIN output winding 8 and the COS output winding 9 are always wound around teeth at positions that are 180° apart, resulting in a cancellation effect.

[0005] Patent No. 4790478

[0006] In the configuration of Patent Document 1, the sub-coil that generates the cancellation effect always outputs a reverse voltage to the main coil, regardless of whether the rotor is eccentric. As a result, the combined voltage of the output coils decreases. On the other hand, if the number of turns of the main coil is increased to increase the output voltage, the fluctuation range of the output voltage when the rotor is eccentric increases, thereby impairing the cancellation effect.

[0007] The present disclosure aims to generate a cancellation effect when the rotor is eccentric, and to suppress a drop in composite voltage when the rotor is not eccentric, in a variable reluctance angle detector.

[0008] (1) A variable reluctance angle detector according to the present disclosure includes a rotor with a shaft angle multiplier of 1X, a stator having 12 teeth, from a first tooth portion to a twelfth tooth portion, arranged circumferentially, an excitation coil, a first output coil, and a second output coil, wherein the excitation coil is forward wound around the first tooth portion and the seventh tooth portion with N1 turns and reverse wound around the fourth tooth portion and the tenth tooth portion with N1 turns, the first output coil is forward wound around the first tooth portion, the second tooth portion, and the twelfth tooth portion and reverse wound around the sixth tooth portion, the seventh tooth portion, and the eighth tooth portion, and the second output coil is reverse wound around the third tooth portion, the fourth tooth portion, and the fifth tooth portion and forward wound around the ninth tooth portion, the tenth tooth portion, and the eleventh tooth portion.

[0009] With the above configuration, a cancellation effect is achieved when the rotor is eccentric, and when the rotor is not eccentric, a combined voltage can be ensured.

[0010] (2) The excitation coil is wound around at least one of the second tooth portion, the third tooth portion, the fifth tooth portion, the sixth tooth portion, the eighth tooth portion, the ninth tooth portion, the eleventh tooth portion, and the twelfth tooth portion with a number of turns N2, and the number of turns N2 may be half or less of the number of turns N1.

[0011] (3) The number of turns of each tooth portion of the first output coil may be equal to the number of turns of each tooth portion of the second output coil.

[0012] (4) When viewed in a plane from the axial direction of the rotor, the rotor may have a hollow portion that is linearly symmetrical with respect to the Y axis, on the convex portion side of the X axis, when the Y axis is an axis extending from the convex portion to the concave portion of the rotor and the X axis is an axis passing through the rotation center of the rotor and perpendicular to the Y axis.

[0013] (5) In the first tooth portion, the fourth tooth portion, the seventh tooth portion, and the tenth tooth portion, the excitation coil may be located radially inside each tooth portion, and the first output coil or the second output coil may be located radially outside each tooth portion, and the excitation coil and the first output coil or the second output coil may be spaced apart.

[0014] With the above configuration, the output voltage can be ensured with a small number of turns, making it possible to reduce the size and weight of the variable reluctance angle detector.

[0015] (6) A variable reluctance angle detector according to the present disclosure includes a rotor with a shaft multiplier angle of 1X, a stator having sixteen teeth from the first tooth portion to the sixteenth tooth portion arranged circumferentially, an excitation coil, a first output coil, and a second output coil, wherein the excitation coil is forward wound around the first tooth portion and the ninth tooth portion with N1 turns and reverse wound around the fifth tooth portion and the thirteenth tooth portion with N1 turns, the first output coil is forward wound around the first tooth portion, the second tooth portion, and the sixteenth tooth portion and reverse wound around the eighth tooth portion, the ninth tooth portion, and the tenth tooth portion, and the second output coil is reverse wound around the fourth tooth portion, the fifth tooth portion, and the sixth tooth portion and forward wound around the twelfth tooth portion, the thirteenth tooth portion, and the fourteenth tooth portion.

[0016] (7) The excitation coil, the first output coil, and the second output coil do not have to be wound around the third tooth portion, the seventh tooth portion, the eleventh tooth portion, and the fifteenth tooth portion.

[0017] According to the present disclosure, in a variable reluctance angle detector, a cancellation effect can be generated when the rotor is eccentric, and a reduction in composite voltage can be suppressed when the rotor is not eccentric.

[0018] FIG. 1 shows the main components of a variable reluctance angle detector 1 according to a first embodiment. FIG. 2 shows the configuration of a stator 4. FIG. 3 schematically shows teeth around which the excitation coil, first output coil, and second output coil are wound. FIG. 4 schematically explains the winding method for the excitation coil, first output coil, and second output coil. FIG. 5 explains the rotor protrusion angle θ. FIG. 6 shows a graph representing the relationship between the rotor protrusion angle θ and the actual measured and simulated values ​​of the induced voltage in the first output coil S101. FIG. 7 shows a graph representing the relationship between the rotor protrusion angle θ and the actual measured and simulated values ​​of the induced voltage in the first output coil S102. FIG. 8 shows a graph representing the relationship between the rotor protrusion angle θ and the actual measured and simulated values ​​of the combined voltage of the first output main coil. FIG. 9 shows a graph representing the relationship between the rotor protrusion angle θ and the actual measured and simulated values ​​of the combined voltage of the first output sub-coil. FIG. 10 illustrates the rotor 5 before and after eccentricity. FIG. 11A is a table illustrating actual measured values ​​and simulated values ​​of induced voltages in the first output coils S101 and S102 for cases with and without eccentricity of the rotor 5, and FIG. 11B is a table illustrating actual measured values ​​and simulated values ​​of composite voltages in the first output main coil and the first output sub-coil for cases with and without eccentricity of the rotor 5. FIG. 12 shows a stator 4 according to a second embodiment. FIG. 13 shows the coil configuration of a variable reluctance angle detector according to the second embodiment. FIG. 14 shows a rotor 5 according to a modified example. FIG. 15A is a top view of the winding configuration according to the modified example from the rotor axial direction, and FIG. 15B shows a two-layer winding configuration according to the conventional technique. FIG. 16 is a table comparing the composite voltage of the output coils between the winding configuration according to the modified example and the two-layer winding configuration according to the conventional technique. FIG. 17 shows the main components of an outer rotor variable reluctance resolver according to a modified example.

[0019] Hereinafter, preferred embodiments of the variable reluctance angle detector according to the present disclosure will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of the present disclosure, and the present disclosure should not be construed as being limited thereto. Needless to say, the embodiments can be modified as appropriate within the scope of the present disclosure.

[0020] First Embodiment As shown in FIGS. 1 to 4 , a variable reluctance angle detector (hereinafter referred to as a “1X resolver”) 1 according to a first embodiment of the present disclosure includes a stator 4 and a rotor 5.

[0021] [Stator 4] As shown in Figures 1 and 2, the stator 4 has a stator core 6 that is generally annular in plan view from the axial direction of the rotor 5. The stator core 6 is formed, for example, by pressing a steel plate of a predetermined thickness into the annular shape, stacking multiple steel plates, and securing them together by caulking or the like. The stator 4 has 12 teeth, numbered 1 to 12, arranged at equal intervals in the circumferential direction on its inner periphery. Each of the 12 teeth 2 protrudes from the stator core 6 toward the center of the annular shape. Coils 3 are wound around the teeth 2. The coils 3 vary depending on the tooth 2 and include one or more of an excitation coil, a first output coil, and a second output coil. The stator 4 has a flange 10 formed on its outer periphery. The flange 10 has a screw hole 10a for fixing the stator 4 in a desired position. The flange 10 may have any shape, and the stator 4 may be fixed using other means.

[0022] [Rotor 5] The rotor 5 has a generally annular shape. The outer periphery of the rotor 5 has a shape such that the gap permeance with the stator 4 changes in a sinusoidal wave (hereinafter referred to as a "SIN wave") manner with respect to the angle θ of the rotation direction of the rotor 5. Like the stator core 6, the rotor 5 is formed by, for example, pressing a steel plate of a predetermined thickness into the annular shape, stacking multiple steel plates, and fastening them together by caulking or the like. A through-hole is provided at the center of the rotor 5, into which the rotor shaft 5a is fitted. In this embodiment, the rotor 5 has a so-called shaft angle multiplier of 1X, which has an outer periphery shape such that the gap permeance with the stator 4 changes by one period of a SIN wave with respect to the angle θ of the rotation direction of the rotor 5. For this reason, one convex portion and one concave portion are formed on the outer periphery. In this embodiment, the angle of the rotor 5 rotated clockwise is referred to as the rotor convex angle θ. 5, the axis passing through the centers of the first and seventh tooth portions of the stator 4 is the Y-axis, and the axis passing through the centers of the fourth and tenth tooth portions is the X-axis. The rotor protrusion angle θ is set to 0 degrees when the protrusion of the rotor 5 faces in the positive direction of the Y-axis.

[0023] [Tooth Portion 2] As described above, the tooth portions 2 are 12 protrusions provided on the inner circumferential side of the stator core 6. As shown in FIG. 2, the 12 tooth portions 2 are numbered sequentially from 1 to 12. While the numbers are numbered clockwise in FIG. 2, they may be numbered counterclockwise. Any of the 12 tooth portions 2 may be designated as the first tooth portion 2. There are no limitations on the method of numbering the tooth portions 2, as long as the numbers are assigned in order without skipping any tooth portion 2. Hereinafter, when distinguishing the individual tooth portions 2 according to the above numbers, alphabets are added to the reference symbols, such as the first tooth portion 2a to the twelfth tooth portion 2l. This also applies to the second embodiment.

[0024] The coils 3 wound around the 12 teeth 2 include excitation coil E01, excitation coil E04, excitation coil E07, and excitation coil E10; first output coil S101, first output coil S102, first output coil S106, first output coil S107, first output coil S108, and first output coil S112; and second output coil S203, second output coil S204, second output coil S205, second output coil S209, second output coil S210, and second output coil S211. All coils are concentratedly wound. One winding direction of the coil wound around the tooth 2 is referred to as "forward winding," and the opposite direction to the forward winding is referred to as "reverse winding." Forward winding and reverse winding can be any winding direction as long as they are opposite. Therefore, the forward winding itself can be either of the two winding directions.

[0025] Therefore, as shown in FIG. 3, an excitation coil E01 and a first output coil S101 are wound forward on the first tooth portion 2a. A first output coil S102 is wound forward on the second tooth portion 2b. A second output coil S203 is wound backward on the third tooth portion 2c. An excitation coil E04 and a second output coil S204 are wound backward on the fourth tooth portion 2d. A second output coil S205 is wound backward on the fifth tooth portion 2e. A first output coil S206 is wound backward on the sixth tooth portion 2f. An excitation coil E07 is wound forward on the seventh tooth portion 2g, and a first output coil S107 is wound backward. A first output coil S108 is wound backward on the eighth tooth portion 2h. A second output coil S209 is wound forward on the ninth tooth portion 2i. The tenth tooth 2j has an excitation coil E10 wound in the reverse direction and a second output coil S210 wound in the forward direction, the eleventh tooth 2k has a second output coil S211 wound in the forward direction, and the twelfth tooth 2l has a first output coil S112 wound in the forward direction.

[0026] [Excitation Coil] The excitation coils E01, E04, E07, and E10 are wound a predetermined number of times N1 around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j, respectively. The excitation coils E01 and E07 and the excitation coils E04 and E10 are wound in opposite directions. In this embodiment, the excitation coils E01 and E07 are wound in the forward direction, and the excitation coils E04 and E10 are wound in the reverse direction. The excitation coils E01 and E07 have the same polarity, and the excitation coils E04 and E10 also have the same polarity. On the other hand, the excitation coils E01 and E07 have the opposite polarity to the excitation coils E04 and E10. The excitation coils E01, E04, E07, and E10 are wound in series around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j. The winding method for the excitation coils E01, E04, E07, and E10 is not particularly limited, but if a flyer-type or nozzle-type winding machine is used to continuously wind one copper wire around each tooth portion 2 and the crossover wires between the tooth portions 2 are entangled in entanglement portions formed on the stator core 6, the excitation coils E01, E04, E07, and E10 can be efficiently concentratedly wound around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j. In this embodiment, no excitation coil is wound around the second tooth portion 2b, the third tooth portion 2c, the fifth tooth portion 2e, the sixth tooth portion 2f, the eighth tooth portion 2h, the ninth tooth portion 2i, the eleventh tooth portion 2k, and the twelfth tooth portion 2l.

[0027] [First Output Coil and Second Output Coil] The first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112 are wound in a concentrated manner with a predetermined number of turns around the first tooth portion 2a, the second tooth portion 2b, the sixth tooth portion 2f, the seventh tooth portion 2g, the eighth tooth portion 2h, and the twelfth tooth portion 2l. The first output coil S101, the first output coil S102, and the first output coil S112 are wound in the forward direction, while the first output coil S106, the first output coil S107, and the first output coil S108 are wound in the reverse direction. Therefore, the first output coil S101, the first output coil S102, and the first output coil S112 have the same polarity. The first output coil S106, the first output coil S107, and the first output coil S108 also have the same polarity as each other, but have an opposite polarity to the first output coil S101, the first output coil S102, and the first output coil S112. The first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112 are wound in series with respect to the first tooth portion 2a, the second tooth portion 2b, the sixth tooth portion 2f, the seventh tooth portion 2g, the eighth tooth portion 2h, and the twelfth tooth portion 2l.

[0028] The second output coil S203, the second output coil S204, the second output coil S205, the second output coil S209, the second output coil S210, and the second output coil S211 are concentratedly wound with a predetermined number of turns on the third tooth portion 2c, the fourth tooth portion 2d, the fifth tooth portion 2e, the ninth tooth portion 2i, the tenth tooth portion 2j, and the eleventh tooth portion 2k. The second output coil S203, the second output coil S204, and the second output coil S205 are wound in the opposite direction, while the second output coil S209, the second output coil S210, and the second output coil S211 are wound in the forward direction. Therefore, the second output coil S203, the second output coil S204, and the second output coil S205 have the same polarity. The second output coils S209, S210, and S211 also have the same polarity as each other, but have opposite polarity to the second output coils S203, S204, and S205. The second output coils S203, S204, S205, S209, S210, and S211 are wound in series with the third tooth portion 2c, the fourth tooth portion 2d, the fifth tooth portion 2e, the ninth tooth portion 2i, the tenth tooth portion 2j, and the eleventh tooth portion 2k.

[0029] The first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112, and the second output coil S203, the second output coil S204, the second output coil S205, the second output coil S209, the second output coil S210, and the second output coil S211 are disposed at positions rotated 90 degrees around the rotor shaft 5a. Therefore, the first output voltages of the first output coils S101, S102, S106, S107, S108, and S112 and the second output voltages of the second output coils S203, S204, S205, S209, S210, and S211 are sine wave signals with a phase shift of 90 degrees. A sine wave with a phase lead of 90 degrees corresponds to a cosine wave (hereinafter referred to as a "cos wave"). In this embodiment, the first output voltage is a cosine wave signal.

[0030] The winding method of the first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112, and the second output coil S203, the second output coil S204, the second output coil S205, the second output coil S209, the second output coil S210, and the second output coil S211 is not particularly limited, similar to the winding method of the excitation coil E01, the excitation coil E04, the excitation coil E07, and the excitation coil E10, but may be a flyer-type or nozzle-type winding. By using a winding machine to continuously wind one copper wire around each tooth portion 2 and winding the jumper wires between each tooth portion 2 in winding portions formed in the stator core 6, it is possible to efficiently wind the first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112, and the second output coil S203, the second output coil S204, the second output coil S205, the second output coil S209, the second output coil S210, and the second output coil S211 in a concentrated manner around each tooth portion 2.

[0031] The first output coil S101, the first output coil S102, the first output coil S106, the first output coil S107, the first output coil S108, and the first output coil S112, and the second output coil S203, the second output coil S204, the second output coil S205, the second output coil S209, the second output coil S210, and the second output coil S211 are wound around different tooth portions 2. No two or more output coils are wound around any tooth portion 2. Furthermore, the excitation coils E01, E04, E07, and E10 are wound around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j, and are not wound around the other tooth portions 2. Therefore, excitation coils and output coils are wound around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j, while only one output coil is wound around the second tooth portion 2b, the third tooth portion 2c, the fifth tooth portion 2e, the sixth tooth portion 2f, the eighth tooth portion 2h, the ninth tooth portion 2i, the eleventh tooth portion 2k, and the twelfth tooth portion 2l. Therefore, only the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j require insulation between the coils; insulation is not required for the other tooth portions 2. Furthermore, since it is sufficient to insulate the excitation coil from the output coil for the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j, only one insulating location is required. This reduced number of insulating locations improves insulation reliability. Furthermore, since the total number of coils is small, the number of winding steps required to form the coils can be reduced, and the component costs of the 1X resolver 1 can also be reduced.

[0032] [Induced Voltage of Output Coil Alone] The induced voltage of the first output coil alone was measured and simulated with the rotor 5 not eccentric, with the rotor protrusion angle θ ranging from 0 to 315 degrees at 45-degree intervals. The excitation current of the excitation coil was 58 mA (RMS: Root Mean Square), 10 kHz, and the impedance was 120 Ω. FIG. 6 shows the induced voltage of the first output coil S101, and FIG. 7 shows the induced voltage of the first output coil S102. In FIGS. 6 and 7, the solid lines are graphs of actual measurements, and the dashed lines are graphs of simulated values.

[0033] As shown in FIG. 6 , the induced voltage in the first output coil S101 is roughly COS-shaped in both the graph V101a of the actual measured values ​​and the graph V101b of the simulated values. When the rotor protrusion angle θ is 0 degrees, the protrusion of the rotor 5 faces the first tooth portion 2a, and the distance from the rotor 5 to the excitation coil E01 and the first output coil S101 is smallest. This results in the highest induced voltage, measured at approximately 3,400 mV. As the rotor 5 rotates and moves away from the excitation coil E01 and the first output coil S101, the induced voltage in the first output coil S101 decreases.

[0034] When the rotor protrusion angle θ reaches 180 degrees, the recessed portion of the rotor 5 faces the first tooth portion 2a, and the distance from the rotor 5 to the excitation coil E01 and the first output coil S101 becomes the largest. As a result, the induced voltage becomes the smallest, with an actual measured value of approximately 1,900 mV. As the rotor 5 rotates further, the rotor 5 approaches the excitation coil E01 and the first output coil S101, and the induced voltage in the first output coil S101 increases.

[0035] Both of the first output coils S101 and S102 are forward-wound. The direction in which the magnetic flux generated by the excitation coil E01 passes through the first output coil S102 is opposite to the direction in which the magnetic flux passes through the first output coil S101. Therefore, the signs of the induced voltages in the first output coils S101 and S102 are opposite to each other.

[0036] The first output coil S101 is wound around the first tooth portion 2a, which is shared with the excitation coil E01. The first output coil S102 is wound around the second tooth portion 2b, which is different from the first tooth portion 2a around which the excitation coil E01 is wound. No excitation coil is wound around the second tooth portion 2b around which the first output coil S102 is wound. Compared to the first output coil S101, the first output coil S102 does not have an excitation coil wound around it, so the absolute value of the induced voltage of the first output coil S102 is smaller than the absolute value of the induced voltage of the first output coil S101.

[0037] As shown in FIG. 7 , the induced voltage in the first output coil S102 is generally COS-shaped in both the graph V102a of the actual measured values ​​and the graph V102b of the simulated values. When the rotor protrusion angle θ is 0 degrees, the induced voltage in the first output coil S102 is highest, with a measured value of approximately −250 mV. As the rotor 5 rotates, the induced voltage in the first output coil S102 decreases. When the rotor protrusion angle θ reaches 180 degrees, the induced voltage in the first output coil S102 is lowest, with a measured value of approximately −390 mV. As the rotor 5 rotates further, the induced voltage in the first output coil S102 increases. Note that the induced voltage in the first output coil S101 has a negative sign. Therefore, the absolute value is smallest when the induced voltage is highest, and largest when the induced voltage is lowest.

[0038] Hereinafter, the first output coil S101 and the first output coil S107 will be referred to as the first output main coil, and the composite voltage of the induced voltages in the first output coil S101 and the first output coil S107 will be referred to as the composite voltage of the first output main coil. The induced voltage in the first output coil S107 has an opposite sign to the induced voltage in the first output coil S101 and is shifted in phase by 180 degrees with respect to the rotor protrusion angle θ. As shown in FIG. 8 , the composite voltage of the first output main coil changes in a COS wave shape with the rotation of the rotor 5 in both the graph Vma of the actual measured values ​​and the graph Vmb of the simulated values, and its amplitude is approximately 3,000 mV.

[0039] The first output coil S102, the first output coil S106, the first output coil S108, and the first output coil S112 are referred to as first output sub-coils, and the composite voltage of the induced voltages in the first output coil S102, the first output coil S106, the first output coil S108, and the first output coil S112 is referred to as the composite voltage of the first output sub-coil. The induced voltages in the first output coil S102 and the first output coil S112 fluctuate in a substantially similar manner with respect to the rotor protrusion angle θ. The induced voltages in the first output coil S106 and the first output coil S108 and the induced voltages in the first output coil S102 and the first output coil S112 have opposite signs and are shifted in phase by 180 degrees with respect to the rotor protrusion angle θ. As shown in FIG. 9, the composite voltage of the first output sub-coil changes in a COS waveform in both the graph Vsa of the actual measured values ​​and the graph Vsb of the simulated values, and its amplitude is approximately 560 mV.

[0040] The first output voltage is a combination of the composite voltage of the first output main coil and the composite voltage of the first output sub-coil. Because the composite voltage of the first output main coil and the composite voltage of the first output sub-coil have the same polarity, the absolute value of the first output voltage does not become smaller than the absolute value of the composite voltage of the first output main coil, even when the composite voltage of the first output sub-coil is combined. In this way, the absolute value of the first output voltage can be ensured.

[0041] [Effect of Eccentricity] Actual measurement values ​​and simulation values ​​were obtained for the induced voltages of the first output coil S101 and the first output coil S102, the composite voltage of the first output main coil, and the composite voltage of the first output sub-coil, both when the rotor 5 is not eccentric and when the rotor 5 is eccentric. As an example of an eccentric rotor 5, as shown in Fig. 10, the rotor 5 was eccentric by 50 micrometers from the center of the stator 4 toward the first tooth portion 2a (positive direction of the Y-axis). The actual measurement values ​​and simulation values ​​were obtained when the rotor protrusion angle θ was 0 degrees.

[0042] When the rotor protrusion angle θ is 0 degrees due to eccentricity of the rotor 5, if the distance from the rotor 5 to the excitation coil E01 and the first output coil S101 decreases, the absolute value of the induced voltage in the first output coil S101 increases. In Fig. 11A, the absolute value of the actually measured induced voltage in the first output coil S101 increases from 3383.8 mV to 3467.1 mV. The absolute value of the simulated value also increases similarly, from 3018.2 mV to 3175.9 mV.

[0043] When the rotor protrusion angle θ is 0 degrees and the distance from the rotor 5 to the excitation coil E01 and the first output coil S101 becomes small due to eccentricity of the rotor 5, the absolute value of the induced voltage in the first output coil S102 also increases, similar to the induced voltage in the first output coil S101. In Fig. 11(A) , the measured value of the induced voltage in the first output coil S102 decreases from -249.8 [mV] to -264.8 [mV], and the simulated value also decreases from -209.6 [mV] to -233.9 [mV], and both absolute values ​​increase.

[0044] 11B, when the rotor 5 is made eccentric, the measured combined voltage of the first output main coil increases from 1520.5 mV to 1579.2 mV, and the simulated combined voltage increases from 1704.3 mV to 1866.8 mV. In contrast, when the rotor is made eccentric, the measured combined voltage of the first output sub-coil decreases from 134.3 mV to 118.8 mV, and the simulated combined voltage also decreases from 311.6 mV to 155.1 mV.

[0045] When the rotor 5 is eccentric, as described above, a cancellation effect occurs in the first output voltage, in which an increase in the composite voltage of the first output main coil is offset by a decrease in the composite voltage of the first output sub-coil, thereby suppressing fluctuations in the first output voltage due to the eccentricity of the rotor 5.

[0046] Since the first output coil and the second output coil have the same induced voltage characteristics, the above explanation regarding the first output coil also applies to the second output coil. Therefore, the magnitude of the second output voltage can be ensured. Furthermore, a cancellation effect occurs in the second output voltage, so fluctuations due to eccentricity of the rotor 5 are suppressed.

[0047] [Second embodiment] A 1X resolver according to a second embodiment has a configuration generally similar to that of the 1X resolver 1 according to the first embodiment, but differs in that the stator has 16 teeth 302, as shown in Fig. 12. In the following description, members common to the 1X resolver 1 according to the first embodiment will be assigned the same reference numerals.

[0048] In this embodiment, a total of 12 coils are wound around the 16 tooth portions 302. Specifically, as shown in Fig. 13, the first tooth portion 302a, the second tooth portion 302b, the fourth tooth portion 302d to the sixth tooth portion 302f, the eighth tooth portion 302h to the tenth tooth portion 302j, the twelfth tooth portion 302l to the fourteenth tooth portion 302n, and the sixteenth tooth portion 302p according to this embodiment correspond to the first tooth portion 2a to the twelfth tooth portion 2l according to the first embodiment, respectively. The first tooth portion 302a, the second tooth portion 302b, the fourth tooth portion 302d to the sixth tooth portion 302f, the eighth tooth portion 302h to the tenth tooth portion 302j, the twelfth tooth portion 302l to the fourteenth tooth portion 302n, and the sixteenth tooth portion 302p are wound with coils common to the first tooth portion 2a to the twelfth tooth portion 2l according to the first embodiment. For example, the first tooth portion 302a according to this embodiment is wound with an excitation coil E401 and a first output coil S401, similar to the excitation coil E01 and the first output coil S101 wound around the first tooth portion 2a according to the first embodiment. The other tooth portions 302 are as shown in FIG. 13 . No coils are wound around the third tooth portion 302c, the seventh tooth portion 302g, the eleventh tooth portion 302k, and the fifteenth tooth portion 302o. Even in this way, as with the 1X resolver 1 according to the first embodiment, the magnitude of the first output voltage and the second output voltage can be ensured, and a cancellation effect can be generated when the rotor 5 is eccentric.

[0049] [Effects of the Embodiments] (1) The 1X resolver according to the above embodiment can suppress a decrease in output voltage when the rotor is not eccentric, and can generate a cancellation effect when the rotor is eccentric. Therefore, the rotor protrusion angle θ can be detected with high accuracy regardless of whether the rotor is eccentric or not.

[0050] In the configuration of Patent Document 1, the sub-coil always outputs a reverse voltage to the main coil even if the rotor 5 is not eccentric. This causes a problem in that the absolute value of the combined voltage obtained by combining the induced voltage of the main coil and the induced voltage of the sub-coil becomes small. In this embodiment, the polarity of the combined voltage of the first output main coil shown in FIG. 8 and the combined voltage of the first output sub-coil shown in FIG. 9 always matches. This prevents the problem of the absolute value of the first output voltage becoming small, which is obtained by combining the combined voltage of the first output main coil and the combined voltage of the first output sub-coil.

[0051] Furthermore, according to the above embodiment, when the rotor 5 is eccentric, a cancellation effect can be obtained in which the composite voltage of the first output sub-coil fluctuates so as to offset the fluctuation in the composite voltage of the first output main coil. Because this cancellation effect is extremely large, even if the rotor 5 is eccentric, the fluctuations in the first output voltage and the second output voltage are reduced, preventing the deterioration of electrical errors. Therefore, the rotor protrusion angle θ can be detected with high accuracy.

[0052] Unlike brushless angle detectors, variable reluctance angle detectors do not require windings on the rotor, making it easy to reduce costs. Furthermore, variable reluctance angle detectors with a shaft angle multiplier of 2X or more have equal output voltages at rotor salient angles θ of 2 or more, so they require a zero-point return operation when powered on. In contrast, variable reluctance angle detectors with a shaft angle multiplier of 1X have a one-to-one correspondence between the rotor salient angle θ and the output voltage, so they can specify the rotor salient angle θ and operate without a zero-point return operation when powered on. With regard to such 1X resolvers, the above-described embodiments enable the rotor salient angle θ to be detected with high accuracy even if the rotor 5 is eccentric, making them industrially useful.

[0053] (2) The number of turns of the excitation coil, the first output coil, and the second output coil can all be reduced, and the output voltage can be ensured, so the 1X resolver can be made smaller and lighter.

[0054] [Variations] (1) In the above first embodiment, an example has been described in which the excitation coil is wound only around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j. However, it goes without saying that the present disclosure is not limited to this, and the excitation coil may also be wound around the second tooth portion 2b, the third tooth portion 2c, the fifth tooth portion 2e, the sixth tooth portion 2f, the eighth tooth portion 2h, the ninth tooth portion 2i, the eleventh tooth portion 2k, and the twelfth tooth portion 2l. However, in order to obtain a cancellation effect sufficient to maintain the detection accuracy of the rotation angle even when the rotor 5 is eccentric, it is desirable that the number of turns N2 of the excitation coil wound around the second tooth portion 2b, the third tooth portion 2c, the fifth tooth portion 2e, the sixth tooth portion 2f, the eighth tooth portion 2h, the ninth tooth portion 2i, the eleventh tooth portion 2k, and the twelfth tooth portion 2l be half or less of the number of turns N1 of the excitation coil E01, the excitation coil E04, the excitation coil E07, and the excitation coil E10 wound around the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j. This is because if the number of turns N2 exceeds half of the number of turns N1, the cancellation effect cannot be obtained.

[0055] In the second embodiment, an example was described in which no excitation coil is wound around the third tooth portion 302c, the seventh tooth portion 302g, the eleventh tooth portion 302k, and the fifteenth tooth portion 302o. However, it goes without saying that the present disclosure is not limited to this. Regarding the excitation coil, the excitation coil may be wound as long as the number of turns N2 is half or less than the number of turns N1 of the excitation coils E401, E404, E407, and E410 wound around the first tooth portion 302a, the fifth tooth portion 302e, the ninth tooth portion 302i, and the thirteenth tooth portion 302m. Even in this case, the effects of the present disclosure can be obtained. This is because, even in this case, if the number of turns N2 exceeds half the number of turns N1, the cancellation effect cannot be obtained.

[0056] (2) In the above embodiment, the rotor 5 is solid. However, the present disclosure is not limited to this, and the rotor 5 may have a cavity. In FIG. 14 , the Y axis passes through the tip of the convex portion of the rotor 5 and the deepest recess of the recess. The X axis is perpendicular to the Y axis at the center of rotation of the rotor 5. A rotor shaft 5a is fitted into the rotor 5. The rotor 5 is continuously connected along the Y axis from the outer periphery of the through hole in which the rotor shaft 5a is fitted to the tip of the convex portion. Furthermore, when viewed from above from the direction of the rotor shaft 5a, a pair of cavities 5b are provided on the side of the convex portion relative to the X axis, which are symmetrical with respect to the Y axis. In this top view, the cavities 5b are approximately fan-shaped. However, the top view shape of the cavities 5b is not limited to a fan-shaped shape, and may have other shapes.

[0057] The rotor 5 has an unbalanced outer peripheral shape that is not rotationally symmetrical about the rotor shaft 5a, so it is necessary to prevent vibration during high-speed rotation. Furthermore, because the rotor 5 is long from the center of the rotor shaft 5a toward the tip of the convex portion and has a large mass, it is also necessary to prevent deformation of the convex portion due to centrifugal force. By providing the hollow portion 5b, it is possible to reduce or eliminate the imbalance in mass distribution, thereby preventing vibration and deformation of the convex portion during high-speed rotation. Furthermore, because a magnetic circuit is formed without attenuating the magnetic flux on the Y-axis side and the X-axis side, it is possible to prevent a decrease in the first output voltage and the second output voltage due to the hollow portion 5b.

[0058] (3) In the above embodiment, the excitation coils E01 and E07 and the first output coils S101 and S107 are wound around the first tooth portion 2a and the seventh tooth portion 2g, respectively, and the excitation coils E04 and E10 and the second output coils S204 and S210 are wound around the fourth tooth portion 2d and the tenth tooth portion 2j, respectively. In this modification, as shown in Fig. 15A, the excitation coils E01, E04, E07, and E10 are located on the tooth tip side of each tooth portion 2, in other words, on the radially inner side, on the first tooth portion 2a, the fourth tooth portion 2d, the seventh tooth portion 2g, and the tenth tooth portion 2j. The first output coil S101 and the first output coil S107, and the second output coil S204 and the second output coil S210 are located radially outside of each tooth portion 2 and are spaced apart from the excitation coil E01, the excitation coil E04, the excitation coil E07, and the excitation coil E10.

[0059] In a conventional resolver, the excitation coil E01 and the first output coil S101 are wound around the circumferential surface of the tooth portion 2 in a two-layer structure, with the excitation coil E01 as the upper layer and the first output coil S101 as the lower layer, as shown in FIG. 15B . In contrast, by concentrating the winding of the excitation coil E01 around the tip of the tooth portion 2, as in this modified example, the output voltage can be increased compared to the conventional resolver. In the example shown in FIG. 16 , if the output voltage of the conventional technique (two-layer winding) is 1670 mV, this modified example can obtain an output voltage of 1802 mV, even with the same number of windings. This is 107.9% larger than the conventional technique (two-layer winding). Similarly, for the same output voltage, the number of windings of the excitation coil E01 can be reduced, thereby enabling the 1X resolver to be made smaller and lighter.

[0060] (4) In the above embodiment, an inner rotor type 1X resolver 1 has been described as an example. However, it goes without saying that the present disclosure is not limited to this, and the 1X resolver according to the present disclosure may be an outer rotor type. In an inner rotor type, the stator 4 surrounds the rotor 5, whereas in an outer rotor type, as shown in FIG. 17 , the rotor 605 surrounds the stator 604. Twelve teeth 602 are provided on the outer periphery of the stator 604 at equal intervals in the circumferential direction. The teeth 602 protrude from the outer periphery of the stator 604 toward the inner periphery of the rotor 605. A coil 603 is wound around the teeth 602. The 12 teeth 602 are numbered from 1 to 12. The numbers assigned to the teeth 602 are arbitrary, except that they are assigned sequentially in the circumferential direction, as in the 1X resolver 1 according to the above embodiment. The details of the coils 603 wound around the first to twelfth tooth portions 602 are the same as those in FIG.

[0061] The rotor 605 is supported by a rotor shaft (not shown) and is rotatable relative to the stator 604. The inner periphery of the rotor 605 is shaped so that the gap permeance varies sinusoidally with the rotation angle θ of the rotor 605. Therefore, when the rotor 605 rotates, the output voltage varies sinusoidally according to the rotation angle θ of the rotor 605. The rotation angle θ of the rotor 605 can be determined from the output voltage that varies in this manner. As with the inner rotor 1X resolver 1, this outer rotor type 1X resolver 601 can also generate a cancellation effect when the rotor is eccentric and suppress a decrease in the composite voltage when the rotor is not eccentric.

[0062] DESCRIPTION OF SYMBOLS 1,601... Variable reluctance angle detector 2,302,602... Tooth portion 3,603... Coil 4,304,604... Stator 5,605... Rotor 5a... Rotor shaft 6,306... Stator core 10,310... Flange portion 10a,310a... Screw hole E01,E04,E07,E10,E401,E404,E407,E410... Excitation coil S101,S102,S106,S107,S108,S112,S401,S402,S406,S407,S408,S412... First output coil S203, S204, S205, S209, S210, S211, S503, S504, S505, S509, S510, S511... Second output coil V101a, V101b, V102a, V102b, Vma, Vmb, Vsa, Vsb... Graph

Claims

1. A variable reluctance angle detector comprising: a rotor with a shaft multiplier of 1X; a stator having 12 teeth, from the first tooth portion to the twelfth tooth portion, arranged circumferentially; an excitation coil; a first output coil; and a second output coil, wherein the excitation coil is forward wound around the first tooth portion and the seventh tooth portion with N1 turns and reverse wound around the fourth tooth portion and the tenth tooth portion with N1 turns; the first output coil is forward wound around the first tooth portion, the second tooth portion, and the twelfth tooth portion and reverse wound around the sixth tooth portion, the seventh tooth portion, and the eighth tooth portion; and the second output coil is reverse wound around the third tooth portion, the fourth tooth portion, and the fifth tooth portion and forward wound around the ninth tooth portion, the tenth tooth portion, and the eleventh tooth portion.

2. A variable reluctance angle detector as set forth in claim 1, wherein the excitation coil is wound around at least one of the second, third, fifth, sixth, eighth, ninth, eleventh and twelfth teeth with N2 turns, and N2 is equal to or less than half of N1.

3. A variable reluctance angle detector according to claim 1 or 2, wherein the number of turns on each tooth of the first output coil is equal to the number of turns on each tooth of the second output coil.

4. A variable reluctance angle detector as claimed in claim 1 or 2, wherein the rotor has a cavity that is symmetrical with respect to the Y axis, on the side of the convex portion of the rotor rather than the X axis, when the Y axis is defined as an axis extending from the convex portion to the concave portion of the rotor and the X axis is defined as an axis passing through the center of rotation of the rotor and perpendicular to the Y axis, in a plan view from the axial direction of the rotor.

5. A variable reluctance angle detector as described in claim 1 or 2, wherein in the first, fourth, seventh and tenth tooth portions, the excitation coil is located radially inside each tooth portion, and the first output coil or the second output coil is located radially outside each tooth portion, and the excitation coil and the first output coil or the second output coil are spaced apart.

6. A variable reluctance angle detector comprising: a rotor with a shaft multiplier of 1X; a stator having 16 teeth, from the 1st tooth portion to the 16th tooth portion, arranged circumferentially; an excitation coil; a first output coil; and a second output coil, wherein the excitation coil is forward wound around the 1st tooth portion and the 9th tooth portion with N1 turns and reverse wound around the 5th tooth portion and the 13th tooth portion with N1 turns; the first output coil is forward wound around the 1st tooth portion, the 2nd tooth portion, and the 16th tooth portion and reverse wound around the 8th tooth portion, the 9th tooth portion, and the 10th tooth portion; and the second output coil is reverse wound around the 4th tooth portion, the 5th tooth portion, and the 6th tooth portion and forward wound around the 12th tooth portion, the 13th tooth portion, and the 14th tooth portion.

7. A variable reluctance angle detector according to claim 6, wherein the excitation coil, the first output coil and the second output coil are not wound around the third tooth portion, the seventh tooth portion, the eleventh tooth portion and the fifteenth tooth portion.

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