Resolver

Abstract

The resolver includes a first substrate (21) having a plurality of layers (Lf1, Lb1) and two-phase coils (11, 12). Each of the two-phase coils (11, 12) has, as a portion forming one magnetic pole, a first portion (11f, 12f) extending in a first direction (Dc1) with respect to the center of the magnetic pole in the common layer (Lf1) and a second portion (11b, 12b) extending in a second direction (Dc2) with respect to the center of the magnetic pole in the other layer (Lb1) other than the common layer and stacked on the first portion (12f, 11f) of the coil (12, 11) of a phase different from the coil (11, 12). Each of the first portion (11f, 12f) and the second portion (11b, 12b) has a substantially closed shape formed by winding a first conductive wire (W11, W12) around the center of a magnetic pole, and is electrically connected to each other via a single through hole (11h, 12h).

Description

[Technical field]

[0001] The present invention relates to a resolver that detects a rotation angle of a rotor relative to a stator. [Background technology]

[0002] Conventionally, in a resolver that detects the rotation angle of a rotor relative to a stator, a structure in which two-phase sheet coils are formed in multiple layers is known. For example, Patent Document 1 discloses a resolver in which a sine wave coil and a cosine wave coil (two-phase coils) are formed as detection coils in both a first detection coil layer and a second detection coil layer.

[0003] In Patent Document 1, the sine wave coil and the cosine wave coil are each divided and arranged in the first and second detection coil layers, respectively, and arranged at positions corresponding to each other. Specifically, the sine wave split coil constituting a part of the sine wave coil on the first detection coil layer is stacked with the cosine wave split coil constituting the other part of the cosine wave coil on the second detection coil layer. Also, the cosine wave split coil constituting a part of the cosine wave coil on the first detection coil layer is stacked with the sine wave split coil constituting the other part of the sine wave coil on the second detection coil layer.

[0004] Patent Document 1 claims that this makes it possible to keep constant the positional relationship (gap) between each of the sine wave coil and cosine wave coil and the excitation coil facing these coils, thereby reducing errors (gain differences) that occur due to changes in the gap. It also claims that by arranging the sine wave coil and cosine wave coil so that a sine wave or cosine wave detection signal is output when a uniform magnetic flux facing in the same direction acts, an appropriate detection signal can be obtained for the detection coil as a whole. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-137633 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order to suppress the gain difference between the coils of two phases, it is necessary to suppress the impedance between the excitation coil and the sine wave coil, the impedance between the excitation coil and the cosine wave coil, and the difference between these impedances. For this reason, when a part of the coil of each phase and the other part are arranged on different layers, it is necessary to provide a connection part in the coil of each phase that penetrates the substrate having these layers and electrically connects the part and the other part. However, at the connection part, the resistance value of the wiring is likely to vary due to manufacturing reasons (e.g., etching and plating).

[0007] In the resolver disclosed in Patent Document 1, the sine wave split coils of the first detection coil layer and the sine wave split coils of the second detection coil layer are each formed in a U-shape with their openings facing each other in the circumferential direction, and a conductor wire alternately travels back and forth between the first detection coil layer and the second detection coil layer to form one sine wave coil. A cosine wave coil is also formed in the same manner. In this way, when a plurality of connection points are provided so that the conductor wire alternately travels back and forth between the first detection coil layer and the second detection coil layer, a difference in wiring resistance due to the above-mentioned variation in resistance value may occur between the two-phase coils. This may cause the electrical characteristics of the two-phase coils to differ from each other, leading to a deterioration in the detection accuracy of the resolver. Note that this problem is not limited to the case where the two-phase coils are provided as detection coils, but may also occur when the two-phase coils are provided as excitation coils.

[0008] The present invention has been devised in view of such problems, and has as one object to suppress the wiring resistance difference occurring between the coils of two phases in a resolver in which the coils of two phases are arranged on a substrate having multiple layers, and to improve the detection accuracy of the resolver. Note that this object is not limited to this object, and another object of the present invention is to achieve an effect that is derived from each configuration shown in the below-mentioned embodiment of the invention and that cannot be obtained by the conventional technology. [Means for solving the problem]

[0009] The disclosed resolver can be realized as the aspects (application examples) disclosed below, and solves at least part of the above problems.

[0010] The resolver disclosed herein is a resolver for detecting a rotation angle of a rotor relative to a stator, and includes a sheet-like first substrate provided on one of the stator and the rotor and having a plurality of layers stacked in a rotation axis direction of the rotor, and sheet-like two-phase coils provided on the first substrate and transmitting AC signals whose electrical angle phases differ from each other by 90 degrees. Each of the two-phase coils has, as a portion forming one magnetic pole, a first portion extending in a first circumferential direction with the center of the magnetic pole as a reference in one common layer of the plurality of layers, and a second portion extending in a second direction opposite to the first direction with the center of the magnetic pole as a reference in the other layer of the plurality of layers other than the common layer, and stacked on the first portion of the coil of a different phase from the coil. Each of the first portion and the second portion has a substantially closed shape formed by winding a first conductor around the center of the magnetic pole, and is electrically connected to each other via a single through hole. Effect of the Invention

[0011] According to the disclosed resolver, the wiring resistance difference occurring between the coils of two phases can be suppressed, and the detection accuracy of the resolver can be improved. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a schematic diagram showing a structure of a resolver according to an embodiment; [Diagram 2] 2 is a plan view showing a first substrate of a stator and a second substrate of a rotor included in the resolver shown in FIG. 1, arranged side by side. [Diagram 3] 3 is a plan view showing the first upper layer and the first lower layer of the stator of FIG. 2 side by side. FIG. [Figure 4] 4 is a graph defining the number of turns of a first portion and a second portion of each of two excitation coils arranged in the stator of FIG. 3. [Diagram 5] 3 is a plan view showing the second upper layer and the second lower layer of the rotor of FIG. 2 side by side. [Figure 6] 6 is a graph defining the number of windings on the outer periphery and the inner periphery of each of the upper layer coil and the lower layer coil arranged on the rotor of FIG. 5 . [Figure 7] 10 is a diagram (corresponding to FIG. 3) showing an example of the configuration of two-phase coils of a resolver according to a modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A resolver as an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and is not intended to exclude various modifications and application of techniques not explicitly described in the following embodiment. Each configuration of the present embodiment can be modified in various ways without departing from the spirit of the embodiment.

[0014] The resolver of the embodiment is a detector (sensor) that detects the rotation angle of the rotor that rotates around the center line C relative to the stator. In the following description, the direction in which the center line C extends is defined as the axial direction (the direction of the rotation axis of the rotor), and the direction perpendicular to the axial direction and away from the center line C and toward the center line C is defined as the radial direction. In the radial direction, the center line C side is defined as the radially inner side, and the opposite side (the side away from the center line C) is defined as the radially outer side. The direction perpendicular to the axial direction and going around the center line C is defined as the circumferential direction.

[0015] [1. Overall composition] FIG. 1 is a schematic diagram showing the configuration of a resolver 1 of this embodiment. The resolver 1 includes a stator 2 and a rotor 3, and is a detector (sensor) that detects the rotation angle of the rotor 3 relative to the stator 2, and is applied to, for example, a servo motor (not shown). The stator 2 is a component that is fixed to a casing (not shown) of a device (for example, a servo motor or a device to which a servo motor is attached) to which the resolver 1 is applied. The rotor 3 is a component that is rotatably supported (around a center line C) integrally with a shaft (not shown) relative to the stator 2. The rotor 3 is disposed with a small gap G in a first axial direction Da1 in the axial direction relative to the stator 2. Hereinafter, the direction opposite to the first axial direction Da1 in the axial direction is referred to as a second axial direction Da2.

[0016] The stator 2 and the rotor 3 each include a sheet-like substrate 21, 31. Each substrate 21, 31 is a thin sheet made of insulating resin (e.g., polyimide) and has a disk shape developed around a center line C, for example, as shown in Fig. 2. Fig. 2 is a diagram showing the first substrate 21 of the stator 2 and the second substrate 31 of the rotor 3 side by side, as viewed from the gap G side between the stator 2 and the rotor 3.

[0017] In this embodiment, each of the substrates 21, 31 has two layers, an upper layer Lf and a lower layer Lb, which are stacked in the axial direction, as shown in Fig. 3 and Fig. 5. The first substrate 21 provided in the stator 2 has a first upper layer Lf1 located on the rotor 3 side (i.e., the first axial direction Da1 side) and a first lower layer Lb1 located on the side farther from the rotor 3 than the first upper layer Lf1 (i.e., the second axial direction Da2 side), as shown in Fig. 3. The second substrate 31 provided in the rotor 3 has a second upper layer Lf2 located on the stator 2 side (i.e., the second axial direction Da2 side) and a second lower layer Lb2 located on the side farther from the stator 2 than the second upper layer Lf2 (i.e., the first axial direction Da1 side), as shown in Fig. 5.

[0018] The upper layer Lf and the lower layer Lb are provided on the surface of each of the substrates 21 and 31 facing the gap G and on the surface facing away from the gap G. In Fig. 3 and Fig. 5, the lower layer Lb is shown as seen through from the upper layer Lf (i.e., the gap G side).

[0019] 1, the stator 2 may be provided with a core 22 laminated on the second axial direction Da2 side of the first substrate 21, and a non-magnetic metal plate 23 covering the first substrate 21 and the core 22 from the second axial direction Da2 side. Similarly, the rotor 3 may be provided with a core 32 laminated on the first axial direction Da1 side of the second substrate 31, and a non-magnetic metal plate 33 covering the second substrate 31 and the core 32 from the first axial direction Da1 side.

[0020] 2, a plurality of coils 11-15 (sheet coils) are formed on each of the substrates 21 and 31. That is, the resolver 1 is a sheet-type resolver having a plurality of sheet-shaped coils 11-15. Note that these coils 11-15 are made of, for example, copper foil. By using sheet coils, the coils 11-15 can be made thin, and thus the resolver 1 can be made thin.

[0021] In this embodiment, a resolver 1 of a two-input one-output type (two-phase excitation single-phase output type) with an axial multiplier angle of 1X is illustrated. The resolver 1 has two excitation coils 11 and 12 (two-phase coils), a detection coil 13 (opposing coil), a transmission coil 14, and a reception coil 15. The resolver 1 is also provided with a sine excitation coil 11 and a cosine excitation coil 12 as the two excitation coils 11 and 12, which transmit AC signals whose electrical angle phases differ from each other by 90 degrees. The sine excitation coil 11, the cosine excitation coil 12, and the detection coil 13 are all coils with an axial multiplier angle of 1X, and have magnetic properties that form a magnetic pole pair (N pole and S pole) when a current flows through them.

[0022] 1 and 2, the two excitation coils 11, 12 and the receiving coil 15 are provided on a first substrate 21 and electrically connected to the signal processing circuit 4. The detecting coil 13 and the transmitting coil 14 are provided on a second substrate 31 and electrically connected to each other (connected in series).

[0023] In the first substrate 21, the two excitation coils 11, 12 are arranged, for example, in a circular ring shape centered on the center line C, overlapping in the axial direction. Each excitation coil 11, 12 is configured to form two magnetic poles (one magnetic pole pair) facing in different directions when a current flows in the direction of the white arrow shown in Figs. 2 and 3. The two excitation coils 11, 12 are also configured so that the centers of the magnetic poles are positioned alternately and at equal intervals in the circumferential direction. For convenience, in Figs. 2 and 3, the sine excitation coil 11 is shown by a solid line, and the cosine excitation coil 12 is shown by a dashed line.

[0024] In detail, as shown in Fig. 2, when a current flows in the direction of a solid white arrow, the sine excitation coil 11 is configured to form a magnetic pole facing the back side of the paper (magnetic pole marked with a cross (x) surrounded by a thin solid line, hereinafter referred to as an "S pole") and a magnetic pole facing the front side of the paper (magnetic pole marked with a dot (·) surrounded by a thin solid line, hereinafter referred to as an "N pole"), sandwiched between the center line C. In the following description of the two excitation coils 11 and 12, the 3 o'clock position of the stator 2 shown in Figs. 2 and 3 is set as the origin (0°) of the circumferential direction of the stator 2. The sine excitation coil 11 forms, for example, an S pole centered at the position of 90° (12 o'clock on the paper) and an N pole centered at the position of 270° (6 o'clock on the paper).

[0025] The cosine excitation coil 12 is configured to form an S pole (magnetic pole indicated by an x ​​surrounded by a thin dashed line) and an N pole (magnetic pole indicated by a circle surrounded by a thin dashed line) on either side of a center line C when a current flows in the direction of the dashed white arrow. The cosine excitation coil 12 forms, for example, an S pole centered at the position of 0° (3 o'clock on the paper) and an N pole centered at the position of 180° (9 o'clock on the paper).

[0026] That is, the two excitation coils 11, 12 are configured so that, counterclockwise from the origin in the circumferential direction of the stator 2, the centers of the S pole of the cosine excitation coil 12, the S pole of the sine excitation coil 11, the N pole of the cosine excitation coil 12, and the N pole of the sine excitation coil 11 are positioned with a phase shift of 90° in this order. Note that, since each excitation coil 11, 12 is actually excited by an AC signal input from the signal processing circuit 4, the magnetic pole orientation (polarity) of each excitation coil 11, 12 is not constant but changes over time when the rotation angle of the rotor 3 is detected. The detailed configuration of the two excitation coils 11, 12 will be described later.

[0027] In the first substrate 21, the receiving coil 15 is formed, for example, radially inward of the two exciting coils 11 and 12, in such a shape that a conducting wire (conductor) is arranged to spiral around the center line C.

[0028] In the second substrate 31, the detection coil 13 has, for example, a circular ring shape centered on a center line C, and is disposed opposite the two excitation coils 11 and 12. The detection coil 13 is configured to form a magnetic pole pair of an S pole (magnetic pole marked with an x) and an N pole (magnetic pole marked with a circle) on either side of the center line C when a current flows in the direction of the black arrows shown in Fig. 2 and Fig. 5. Note that the detection coil 13 actually generates an induced current by linking the magnetic fluxes of the excitation coils 11 and 12, and therefore the detection coil 13 does not spontaneously form magnetic poles when detecting the rotation angle of the rotor 3.

[0029] Therefore, strictly speaking, the detection coil 13 is configured to have magnetic properties that form an S pole and an N pole on either side of the center line C when a current flows in the direction of the black arrows shown in Figures 2 and 5. In the following description of the detection coil 13, unless otherwise specified, it is assumed that a current flows in the direction of the black arrows shown in Figures 2 and 5. In the following description of the detection coil 13, the 6 o'clock position of the rotor 3 shown in Figures 2 and 5 is taken as the origin (0°) in the circumferential direction of the rotor 3. The detection coil 13 forms an S pole centered at the position of 180° (12 o'clock on the paper) and an N pole centered at the position of 0° (6 o'clock on the paper), for example.

[0030] As shown in Fig. 5, the detection coil 13 has an upper layer coil 16 (first coil) arranged in the second upper layer Lf2 (first layer) and a lower layer coil 17 (second coil) arranged in the second lower layer Lb2 (second layer). The detection coil 13 is configured to form the above-mentioned one magnetic pole pair by the interaction of the magnetic fluxes formed by the upper layer coil 16 and the lower layer coil 17 when a current flows. For convenience, the upper layer coil 16 is shown by a solid line and the lower layer coil 17 is shown by a dashed line in Fig. 2. A detailed configuration of the detection coil 13 will be described later.

[0031] On the second substrate 31, the transmitting coil 14 is disposed opposite the receiving coil 15. The transmitting coil 14 is formed, for example, radially inward of the detecting coil 13 and has a shape in which a conductor is arranged to spiral around the center line C.

[0032] The signal processing circuit 4 is an electric circuit provided at a position different from the stator 2 and the rotor 3, and as shown in Fig. 1, includes a signal generating circuit 5 and a signal detecting circuit 6. The signal generating circuit 5 generates an amplitude-modulated AC signal and inputs (supplies) it to the exciting coils 11 and 12. The signal detecting circuit 6 outputs angle information corresponding to the rotation angle based on the AC signal returned from the receiving coil 15.

[0033] AC signals whose electrical angle phases differ by 90 degrees from each other are input to the sine excitation coil 11 and the cosine excitation coil 12 from the signal generating circuit 5. More specifically, a cosine wave AC signal is input to the sine excitation coil 11, and a sine wave AC signal is input to the cosine excitation coil 12.

[0034] In the resolver 1, when an AC signal is input from the signal processing circuit 4 to the excitation coils 11 and 12, the excitation coils 11 and 12 are excited to generate a magnetic flux (see the white arrow in FIG. 1). This magnetic flux is linked to the detection coil 13 on the rotor 3 side to generate an induced voltage. As a result, a signal that is phase-modulated according to the rotation angle (relative angle) of the rotor 3 with respect to the stator 2 is generated in the detection coil 13. Then, the transmission coil 14 is excited by the signal transmitted from the detection coil 13 to generate a magnetic flux (see the black arrow in FIG. 1). This magnetic flux is linked to the reception coil 15 on the stator 2 side to generate an induced voltage. The output waveform of this induced voltage is output to the signal processing circuit 4, and the rotation angle of the rotor 3 is obtained based on the phase change of the output waveform. In other words, the resolver 1 is a modulated wave type resolver that inputs an amplitude-modulated AC signal and uses it to detect the rotation angle from the phase-modulated signal generated in the detection coil 13.

[0035] [2. Excitation coil configuration] The configuration of the two excitation coils 11, 12 will be described in detail below with reference to Figs. 2 to 4. As described above, the two excitation coils 11, 12 are arranged on the first substrate 21 in an axially overlapping manner. This allows the excitation coils 11, 12 to be arranged (deployed) widely in the circumferential direction, and the excitation coils 11, 12 can be configured to form a magnetic flux distribution with little distortion over a wide range in the circumferential direction. Therefore, a detection signal (phase-modulated signal) according to the rotation angle of the rotor 3 is obtained by the detection coil 13, improving the detection accuracy of the resolver 1. The magnetic flux distribution with little distortion here means a magnetic flux distribution in which there are few places in the circumferential direction where the magnetic coupling between the excitation coils 11, 12 and the detection coil 13 is lost, and in which there is no sudden change in the magnetic flux.

[0036] Here, the axial positions of the first upper layer Lf1 and the first lower layer Lb1 are slightly different in the first substrate 21. For this reason, it is assumed that, for example, the sine excitation coil 11 is arranged in the first upper layer Lf1 and the cosine excitation coil 12 is arranged in the first lower layer Lb1 as a configuration in which two excitation coils 11 and 12 are stacked on the first substrate 21. In this case, due to a slight difference in the axial positions of the layers Lf1 and Lb1, a magnetic resistance difference (impedance difference) occurs between the sine excitation coil 11 and the cosine excitation coil 12 with respect to the detection coil 13, and the detection accuracy of the resolver 1 may decrease.

[0037] Therefore, each of the two excitation coils 11, 12 is provided with a configuration that suppresses the impedance difference between the two excitation coils 11, 12. Specifically, each of the two excitation coils 11, 12 is provided with a first portion 11f, 12f arranged in a first upper layer Lf1 (common layer, upper layer) and a second portion 11b, 12b arranged in a first lower layer Lb1 (other layer than the common layer, lower layer) as shown in Fig. 3, and the first portion 11f and the second portion 11b, and the first portion 12f and the second portion 12b are combined to form one magnetic pole. Each of the first portions 11f, 12f extends in a first circumferential direction Dc1 (for example, a clockwise direction, a first direction) in the circumferential direction based on the center of the respective magnetic pole. In addition, each second portion 11b, 12b extends in a second circumferential direction Dc2 (e.g., a counterclockwise direction, a second direction) opposite to the first circumferential direction Dc1 based on the center of the respective magnetic pole, and is stacked on a first portion 12f, 11f of the excitation coil 12, 11 of a different (other) phase from the excitation coil 11, 12 that forms the magnetic pole.

[0038] In this embodiment, each of the excitation coils 11 and 12 forms two magnetic poles, an S pole and an N pole. Therefore, each of the excitation coils 11 and 12 has two first portions 11f and 12f and two second portions 11b and 12b. The sine excitation coil 11 has an S pole first portion 11fs and an S pole second portion 11bs as portions that form an S pole, and an N pole first portion 11fn and an N pole second portion 11bn as portions that form an N pole. The cosine excitation coil 12 has an S pole first portion 12fs and an S pole second portion 12bs as portions that form an S pole, and an N pole first portion 12fn and an N pole second portion 12bn as portions that form an N pole.

[0039] Hereinafter, the center position of the S pole of the sine excitation coil 11 (90° position) is referred to as the first S pole center position Pcs1, and the center position of the N pole of the sine excitation coil 11 (270° position) is referred to as the first N pole center position Pcn1. The first S pole center position Pcs1 and the first N pole center position Pcn1 are also collectively referred to as the first center position Pc1. The center position of the S pole of the cosine excitation coil 12 (0° position) is referred to as the second S pole center position Pcs2, and the center position of the N pole of the cosine excitation coil 12 (180° position) is referred to as the second N pole center position Pcn2. The second S pole center position Pcs2 and the second N pole center position Pcn2 are also collectively referred to as the second center position Pc2.

[0040] As a portion forming the S pole of the sine excitation coil 11, the S pole first portion 11fs has a quadrant ring shape (partial ring shape) extending, for example, to a position (0°) (before the position) where the phase differs by 90° in the first circumferential direction Dc1 with respect to the first S pole center position Pcs1 as a reference. The S pole second portion 11bs has a quadrant ring shape extending, for example, to a position (180°) where the phase differs by 90° in the second circumferential direction Dc2 with respect to the position Pcs1 as a reference, and is laminated on the N pole first portion 12fn of the cosine excitation coil 12.

[0041] As a portion forming the N pole of the sine excitation coil 11, the N pole first portion 11fn is a quadrant ring shape extending, for example, to a position (180°) where the phase differs by 90° in the first circumferential direction Dc1 with respect to the first N pole center position Pcn1 as a reference. The N pole second portion 11bn is a quadrant ring shape extending, for example, to a position (0°) where the phase differs by 90° in the second circumferential direction Dc2 with respect to the position Pcn1 as a reference, and is laminated on the S pole first portion 12fs of the cosine excitation coil 12.

[0042] Similarly, as a portion forming the S pole of the cosine excitation coil 12, the S pole first portion 12fs has a quadrant ring shape extending, for example, to a position (270°) where the phase differs by 90° in the first circumferential direction Dc1 with respect to the second S pole center position Pcs2 as a reference. The S pole second portion 12bs has a quadrant ring shape extending, for example, to a position (90°) where the phase differs by 90° in the second circumferential direction Dc2 with respect to the position Pcs2 as a reference, and is layered on the S pole first portion 11fs of the sine excitation coil 11.

[0043] As a portion forming the N pole of the cosine excitation coil 12, the N pole first portion 12fn is a quadrant ring shape extending, for example, to a position (90°) where the phase differs by 90° in the first circumferential direction Dc1 with respect to the second N pole center position Pcn2 as a reference. The N pole second portion 12bn is a quadrant ring shape extending, for example, to a position (270°) where the phase differs by 90° in the second circumferential direction Dc2 with respect to the position Pcn2 as a reference, and is layered on the N pole first portion 11fn of the sine excitation coil 11.

[0044] Incidentally, when a portion forming one magnetic pole is composed of two portions provided on different layers Lf1, Lb1 as described above, the portion needs to have a portion (connection portion) that penetrates the first substrate 21 and electrically connects the portion 11f, 12f provided on the first upper layer Lf1 and the portion 11b, 12b provided on the first lower layer Lb1. However, at such a connection portion, the resistance value of the conductor is likely to vary due to manufacturing reasons (e.g., etching and plating). Such variation in the resistance value of the connection portion is caused by the variation in the wiring resistance of the excitation coils 11, 12, which makes it easy for a difference in wiring resistance to occur between the two excitation coils 11, 12.

[0045] Therefore, each of the two excitation coils 11 and 12 is provided with a configuration for suppressing the above-mentioned wiring resistance difference. Specifically, the first parts 11f and 12f and the second parts 11b and 12b of each excitation coil 11 and 12 are formed into a substantially closed shape by winding conductors W11 and W12 (first conductors) around the center positions Pc1 and Pc2 of the respective magnetic poles, and the first parts 11f and 12f and the second parts 11b and 12b that form one magnetic pole are electrically connected via single through holes 11h and 12h (connection points). This minimizes the number of connection points of the parts that form one magnetic pole, thereby suppressing the wiring resistance difference caused by the variation in resistance value of the connection points. The conductor wire W11 forming the portions 11f and 11b of the sine excitation coil 11 and the conductor wire W12 forming the portions 12f and 12b of the cosine excitation coil 12 are separate conductor wires and are not electrically connected to each other.

[0046] A detailed description will be given focusing on the sine excitation coil 11. The first portion 11f and the second portion 11b of the sine excitation coil 11 are formed, for example, by arranging the conductor W11 so as to surround (circumnavigate) the first central position Pc1, forming a substantially closed shape. Note that the substantially closed shape referred to here means a shape in which the conductor W11 is present all around the first central position Pc1 of the magnetic pole, and does not mean a shape in which the conductor W11 is not present in a part of the periphery of the first central position Pc1, for example, a U-shape or a C-shape.

[0047] Each of the portions 11f, 11b of the sine excitation coil 11 may be formed, for example, in each of the layers Lf1, Lb1 by winding a single conductor W11 in a spiral manner (in a lightning pattern) around the first center position Pc1 as shown in the figure. In this manner, each of the portions 11f, 11b may be formed by the conductor W11 arranged continuously and uninterruptedly in a single stroke in each of the layers Lf1, Lb1. Each of the portions 11f, 11b forms a magnetic pole in an inner region (a region indicated by dotted lines in FIG. 3) of the winding of the conductor W11.

[0048] Furthermore, in this embodiment, the first portion 11f and the second portion 11b are wound so that the number of turns decreases as the portion moves away from the first center position Pc1. That is, the conductor W11 forming each portion 11f, 11b is wound in one direction in a partially circular shape from a starting point (through hole 11h) near the first center position Pc1, and is wound so that the end point is on the outer side of the winding, and is arranged so that the turn-back portion on the opposite side to the first center position Pc1 side is sparser than the turn-back portion on the first center position Pc1 side. The above description focuses on the sine excitation coil 11, but the conductor W12 is also arranged around the second center position Pc2 in the same manner for the cosine excitation coil 12, forming the first portion 12f and the second portion 12b.

[0049] The first portions 11f, 12f and the second portions 11b, 12b are each arranged with the conductor wires W11, W12 so as to have the relationship of the number of turns shown in the graph of Fig. 4. Fig. 4 is a graph defining the number of turns M of each portion 11f, 11b, 12f, 12b in the circumferential direction, where the horizontal axis corresponds to the circumferential angle shown in Fig. 3 and the vertical axis corresponds to the number of turns M of each portion 11f, 11b, 12f, 12b. On the vertical axis, the "(S)" side corresponds to the number of turns M of the portions 11fs, 12fs, 11bs, 12bs that form the S pole, and the "(N)" side corresponds to the number of turns M of the portions 11fn, 12fn, 11bn, 12bn that form the N pole.

[0050] 4, for the sake of convenience, the portions 11fs, 11fn, 12fs, and 12fn arranged on the first upper layer Lf1 are indicated by thicker lines than the portions 11bs, 11bn, 12bs, and 12bn arranged on the first lower layer Lb1. Also, the portions 11fs, 11fn, 11bs, and 11bn of the sine excitation coil 11 are indicated by solid lines, and the portions 12fs, 12fn, 12bs, and 12bn of the cosine excitation coil 12 are indicated by dashed lines.

[0051] 4, the number of turns M of the S-pole first portion 11fs of the sine excitation coil 11 increases from near 0° to near 90°, and is set to a maximum value (5 in this example) near 90°, i.e., near the first S-pole center position Pcs1. The number of turns M of the S-pole second portion 11bs of the sine excitation coil 11 is set symmetrically to the S-pole first portion 11fs, decreasing from near 90° to near 180°.

[0052] The N-pole first portion 11fn of the sine excitation coil 11 is set so that the number of turns M increases from near 180° to near 270°, and reaches a maximum value (5 here) near 270°, i.e., near the first N-pole center position Pcn1. The N-pole second portion 11bn of the sine excitation coil 11 is set so that the number of turns M decreases from near 270° to near 360°, symmetrically to the N-pole first portion 11fn.

[0053] In the sinusoidal excitation coil 11, the number of turns M of each of the portions 11fs, 11bs, 11fn, and 11bn is set to approximate a sinusoidal waveform with one cycle per circumferential revolution, as described above. As a result, when the sinusoidal excitation coil 11 is excited, a magnetic flux distribution is formed in accordance with the change in the number of turns M of each of the portions 11fs, 11bs, 11fn, and 11bn, i.e., a sinusoidal magnetic flux distribution, so that a magnetic flux distribution with little distortion can be obtained.

[0054] The S-pole second portion 12bs of the cosine excitation coil 12 is set so that the number of turns M is maximum (here, 5) near 0°, i.e., near the second S-pole center position Pcs2, and decreases from near 0° to near 90°. The S-pole first portion 12fs of the cosine excitation coil 12 is set so that the number of turns M decreases from near 0° to near -90° (270°) symmetrically to the S-pole second portion 12bs.

[0055] The N-pole first portion 12fn of the cosine excitation coil 12 is set so that the number of turns M increases from near 90° to near 180°, and reaches a maximum value (5 here) near 180°, i.e., near the second N-pole center position Pcn2. The N-pole second portion 12bn of the cosine excitation coil 12 is set so that the number of turns M decreases from near 180° to near 270°, symmetrically to the N-pole first portion 12fn.

[0056] In the cosine excitation coil 12, the number of turns M of each of the portions 12bs, 12fn, 12bn, and 12fs is set to approximate a cosine waveform with one cycle per circumferential revolution, as described above. As a result, when the cosine excitation coil 12 is excited, a magnetic flux distribution is formed in accordance with the change in the number of turns M of each of the portions 12bs, 12fn, 12bn, and 12fs, i.e., a cosine waveform magnetic flux distribution, resulting in a magnetic flux distribution with little distortion.

[0057] In this embodiment, the first portions 11f, 12f and the second portions 11b, 12b each forming one magnetic pole have the same number of turns (maximum number of turns), but the first portions 11f, 12f and the second portions 11b, 12b may have different numbers of turns. For example, the number of turns of the first portions 11f, 12f may be set to be less than the number of turns of the second portions 11b, 12b. This suppresses the impedance difference between the first portions 11f, 12f and the second portions 11b, 12b caused by the difference in the axial positions of the layers Lf1, Lb1.

[0058] In the present embodiment, as shown in Figs. 2 and 3, the radial widths of the first portions 11f, 12f and the second portions 11b, 12b, each of which forms one magnetic pole, are substantially equal to each other, but the radial widths of the first portions 11f, 12f and the second portions 11b, 12b may be different from each other. For example, the radial width of the first portions 11f, 12f may be smaller than the radial width of the second portions 11b, 12b. In other words, the area of ​​the region in which the magnetic pole is formed in the first portions 11f, 12f may be smaller than the area of ​​the region in which the magnetic pole is formed in the second portions 11b, 12b. This suppresses the impedance difference between the first portions 11f, 12f and the second portions 11b, 12b caused by the difference in the axial positions of the layers Lf1, Lb1.

[0059] [3.Detection coil configuration] The configuration of the detection coil 13 will be described in detail below with reference to Figures 2, 5, and 6. As described above, the detection coil 13 has an upper layer coil 16 and a lower layer coil 17, and the magnetic fluxes of the upper layer coil 16 and the lower layer coil 17 interact with each other to form magnetic poles (S pole and N pole) in different directions. Hereinafter, the center position of the S pole of the detection coil 13 (the 180° position of the rotor 3 shown in Figures 2 and 5) will be referred to as the third S pole center position Pcs3, and the center position of the N pole of the detection coil 13 (the 0° position of the rotor 3 shown in Figures 2 and 5) will be referred to as the third N pole center position Pcn3.

[0060] The detection coil 13 is formed by a conductor W13 (second conductor) arranged in the second upper layer Lf2 and the second lower layer Lb2, as shown in Fig. 5. The conductor W13 forming the detection coil 13 is a conductor of a different system from the conductors W11 and W12 forming the excitation coils 11 and 12, and is not electrically connected to these conductors W11 and W12.

[0061] The upper layer coil 16 is a substantially annular shape formed by winding the upper layer conductor Wf arranged in the second upper layer Lf2 (first layer) of the conductor W13 in a first circumferential direction Dc1 (first direction) starting from a radially outer end point. The lower layer coil 17 is a substantially annular shape formed by winding the lower layer conductor Wb arranged in the second lower layer Lb2 (second layer) of the conductor W13 in a second circumferential direction Dc2 (second direction) starting from a radially inner end point. Each of the upper layer conductor Wf and the lower layer conductor Wb is arranged to wind at least two or more turns (multiple turns) around the center line C without turning back in the direction opposite to each winding direction (each of the first circumferential direction Dc1 and the second circumferential direction Dc2), and is electrically connected to each other via the through hole 13h, thereby being continuously provided.

[0062] 5 indicates the wiring direction of the conductor W13 when the upper layer conductor Wf and the lower layer conductor Wb are wired in this order, starting from the outer end point of the winding of the upper layer conductor Wf (i.e., the position of the black arrow in FIG. 5). In other words, this thin arrow indicates the direction of current flow when a current flows in the direction of the black arrow in FIG. 5.

[0063] Each of the upper coil 16 and the lower coil 17 has an outer circumferential portion 16o, 17o and an inner circumferential portion 16i, 17i as portions forming two magnetic poles in mutually different directions. Each of the outer circumferential portions 16o, 17o is a portion extending in the circumferential direction near the outer circumferential edge of each of the upper coil 16 and the lower coil 17, which are substantially annular, and each of the inner circumferential portions 16i, 17i is a portion extending in the circumferential direction radially inward of each of the outer circumferential portions 16o, 17o.

[0064] Upper layer outer peripheral portion 16o of upper layer coil 16 is arranged so as not to overlap partially with upper layer inner peripheral portion 16i of upper layer coil 16 in the circumferential direction, and is arranged at approximately the same circumferential position as lower layer inner peripheral portion 17i of lower layer coil 17. Similarly, lower layer outer peripheral portion 17o of lower layer coil 17 is arranged so as not to overlap partially with lower layer inner peripheral portion 17i in the circumferential direction, and is arranged at approximately the same circumferential position as upper layer inner peripheral portion 16i.

[0065] In this embodiment, the upper layer outer peripheral portion 16o extends in both circumferential directions (first circumferential direction Dc1 and second circumferential direction Dc2) based on the third N-pole center position Pcn3 at a location other than the periphery of the third S-pole center position Pcs3 in the circumferential direction. The lower layer inner peripheral portion 17i is located adjacent to the radially inner side of the upper layer outer peripheral portion 16o. The upper layer inner peripheral portion 16i extends in both circumferential directions based on the third S-pole center position Pcs3 at a location other than the periphery of the third N-pole center position Pcn3 in the circumferential direction. As a result, the upper layer outer peripheral portion 16o and the upper layer inner peripheral portion 16i are arranged so as not to overlap partially in the circumferential direction around the third N-pole center position Pcn3 and the third S-pole center position Pcs3.

[0066] In this way, since upper layer outer peripheral portion 16o is provided on the third N-pole central position Pcn3 side and upper layer inner peripheral portion 16i is provided on the third S-pole central position Pcs3 side, upper layer coil 16 can be said to be eccentric toward the third N-pole central position Pcn3 side with respect to center line C. When a current flows in the direction of the black arrow shown in Fig. 5, upper layer coil 16 generates an N-pole magnetic flux in a substantially circular upper layer region Rf (a region shown by thick dots in Fig. 5) developed around a position closer to the third N-pole central position Pcn3 than the center line C.

[0067] The same is true for the lower layer coil 17. That is, the lower layer outer peripheral portion 17o extends in both circumferential directions with the third S pole center position Pcs3 as a reference, except for the periphery of the third N pole center position Pcn3 in the circumferential direction. The upper layer inner peripheral portion 16i is located adjacent to the radially inner side of the lower layer outer peripheral portion 17o. The lower layer inner peripheral portion 17i extends in both circumferential directions with the third N pole center position Pcn3 as a reference, except for the periphery of the third S pole center position Pcs3 in the circumferential direction. As a result, the lower layer outer peripheral portion 17o and the lower layer inner peripheral portion 17i are arranged so as not to overlap partially in the circumferential direction around the third N pole center position Pcn3 and the third S pole center position Pcs3.

[0068] In this way, since lower layer outer peripheral portion 17o is provided on the third S-pole central position Pcs3 side and lower layer inner peripheral portion 17i is provided on the third N-pole central position Pcn3 side, lower layer coil 17 can be said to be eccentric toward the third S-pole central position Pcs3 side with respect to center line C. When a current flows in the direction of the black arrow shown in Fig. 5, lower layer coil 17 generates an S-pole magnetic flux in a substantially circular lower layer region Rb (a region shown by light dots in Fig. 5) developed around a position closer to the third S-pole central position Pcs3 than the center line C.

[0069] In the detection coil 13, when a current flows in the direction of the black arrows shown in Fig. 2 and Fig. 5, the magnetic flux of the upper coil 16 and the lower coil 17 interact with each other. As a result, in the region radially inward of the inner circumferential parts 16i and 17i, the magnetic flux of the upper coil 16 and the magnetic flux of the lower coil 17 cancel each other out, and as shown in Fig. 2, magnetic poles of different orientations are formed between the upper outer circumferential part 16o and the lower inner circumferential part 17i, and between the upper inner circumferential part 16i and the lower outer circumferential part 17o. In more detail, an N pole is formed in a semicircular ring-shaped region (shown by thick dots in Fig. 2) centered on the third N pole central position Pcn3 between the upper outer circumferential part 16o and the lower inner circumferential part 17i, and an S pole is formed in a semicircular ring-shaped region (shown by thin dots in Fig. 2) centered on the third S pole central position Pcs3 between the upper inner circumferential part 16i and the lower outer circumferential part 17o.

[0070] 5, the upper-layer outer peripheral portion 16o is formed of a plurality of outer windings Wfo of the upper-layer conductor Wf that extend in both circumferential directions with the third N-pole central position Pcn3 as a reference. The upper-layer inner peripheral portion 16i is formed of a plurality of inner windings Wfi of the upper-layer conductor Wf that extend in both circumferential directions with the third S-pole central position Pcs3 as a reference. The plurality of windings Wfo, Wfi that form the upper-layer outer peripheral portion 16o and the upper-layer inner peripheral portion 16i are set so that the number of windings Wfo, Wfi decreases with increasing distance from the central positions Pcn3, Pcs3 of the respective magnetic poles.

[0071] Furthermore, in this embodiment, the upper layer conductor Wf is provided with a plurality of connection wires Wfc that connect the plurality of outer windings Wfo and the plurality of inner windings Wfi. The upper layer conductor Wf is arranged so as to form an outer winding Wfo, an inner winding Wfi, and two connection wires Wfc that connect the ends of these windings Wfo and Wfi each time it makes one turn around the center line C.

[0072] The upper layer conductor Wf is arranged, for example, starting from a position near the third N-pole center position Pcn3 and radially outer than the position where the upper layer outer peripheral portion 16o is formed, toward the first circumferential direction Dc1 to form the outer winding Wfo. Then, just before reaching the third S-pole center position Pcs3, it is bent radially inward to form one connection line Wfc, the inner winding Wfi, and the other connection line Wfc in this order. In detail, the upper layer conductor Wf is arranged to form one connection line Wfc toward the radially inner side, to form the inner winding Wfi toward the first circumferential direction Dc1, and then to form the other connection line Wfc toward the radially outer side. The upper layer conductor Wf is arranged in this way so that a part of the outer circle in which the outer winding Wfo extends is cut out around the third S-pole center position Pcs3. In this embodiment, each connection wire Wfc extends in the radial direction as shown in the figure, but each connection wire Wfc may extend in a direction inclined with respect to the radial direction. For example, one of the connection wires Wfc may be arranged to extend radially inward in the first circumferential direction Dc1, and the other connection wire Wfc may be arranged to extend radially outward in the first circumferential direction Dc1. The upper layer conductor Wf is then arranged again in the first circumferential direction Dc1 to form the outer winding Wfo, and when passing near the third N-pole center position Pcn3, it is arranged slightly radially inward from the previous outer winding Wfo, and this is repeated.

[0073] The upper layer conductor Wf is arranged such that the circumferential width of the cutout formed by the pair of connecting wires Wfc and the inner winding Wfi increases with each turn around the center line C. As a result, both the upper layer outer peripheral portion 16o and the upper layer inner peripheral portion 16i are configured such that the number of windings Wfo, Wfi decreases the farther they are from the center positions Pcn3, Pcs3 of the respective magnetic poles.

[0074] In this embodiment, in order to shift the phase between the circumferential position of the connection line Wfc of the upper layer conductor Wf and the circumferential position of the connection line Wbc of the lower layer conductor Wb, which will be described later, the entire upper layer coil 16 is arranged at a predetermined angle in the first circumferential direction Dc1 with respect to a diameter line connecting the third S-pole center position Pcs3 and the third N-pole center position Pcn3. In detail, the outer winding Wfo is extended on both sides in the circumferential direction with a first shift position P1, which is shifted by a predetermined angle in the first circumferential direction Dc1 from the third N-pole center position Pcn3, as its center. The inner winding Wfi is extended on both sides in the circumferential direction with a second shift position P2, which is shifted by a predetermined angle in the first circumferential direction Dc1 from the third S-pole center position Pcs3, as its center. The predetermined angle may be set according to the maximum number of windings Wfo and Wfi.

[0075] The lower-layer outer peripheral portion 17o is formed of a plurality of outer windings Wbo of the lower-layer conductor Wb that extend in both circumferential directions with the third S-pole center position Pcs3 as a reference. The lower-layer inner peripheral portion 17i is formed of a plurality of inner windings Wbi of the lower-layer conductor Wb that extend in both circumferential directions with the third N-pole center position Pcn3 as a reference. The plurality of windings Wbo, Wbi that form the lower-layer outer peripheral portion 17o and the lower-layer inner peripheral portion 17i are set so that the number of windings Wbo, Wbi decreases with increasing distance from the center positions Pcs3, Pcn3 of the respective magnetic poles, similar to the windings Wfo, Wfi of the upper-layer outer peripheral portion 16o and the upper-layer inner peripheral portion 16i.

[0076] Furthermore, in this embodiment, the lower layer conductor Wb is provided with a plurality of connection wires Wbc that connect the plurality of outer windings Wbo and the plurality of inner windings Wbi, similar to the upper layer conductor Wf. The lower layer conductor Wb is arranged so as to form an outer winding Wbo, an inner winding Wbi, and two connection wires Wbc that connect the ends of these windings Wbo, Wbi, for each turn around the center line C.

[0077] The lower layer conductor Wb is arranged, for example, starting from a position (position of the through hole 13h) near the third N-pole center position Pcn3 and radially inward from the position where the lower layer inner circumferential portion 17i is formed, toward the second circumferential direction Dc2 to form the inner winding Wbi. Then, just before reaching the third S-pole center position Pcs3, it is bent radially outward to form one connection line Wbc, the outer winding Wbo, and the other connection line Wbc in this order. In more detail, the lower layer conductor Wb is arranged to form one connection line Wbc toward the radially outward direction, and then to form the outer winding Wbo toward the second circumferential direction Dc2, and then to form the other connection line Wbc toward the radially inward direction. The lower layer conductor Wb is arranged in this way to protrude a part of the inner circle in which the inner winding Wbi extends around the third N-pole center position Pcn3. In this embodiment, each connection wire Wbc extends in the radial direction as shown in the figure, but each connection wire Wbc may extend in a direction inclined with respect to the radial direction. For example, one of the connection wires Wbc may be arranged to extend radially outward and in the second circumferential direction Dc2, and the other connection wire Wbc may be arranged to extend radially inward and in the second circumferential direction Dc2. The lower layer conductor Wb is then arranged again in the second circumferential direction Dc2 to form the inner winding Wbi, and when passing near the third N-pole center position Pcn3, it is arranged slightly radially outward from the previous inner winding Wbi, and this is repeated.

[0078] The lower-layer conductor Wb is arranged such that the circumferential width of a protruding portion formed of a pair of connecting wires Wbc and an outer winding Wbo increases with each turn around the center line C. As a result, both the lower-layer outer peripheral portion 17o and the lower-layer inner peripheral portion 17i are configured such that the number of windings Wbo, Wbi decreases the farther they are from the center positions Pcs3, Pcn3 of the magnetic poles.

[0079] In this embodiment, the entire lower layer coil 17 is arranged to be inclined at a predetermined angle in the second circumferential direction Dc2 with respect to a diameter line connecting the third S-pole center position Pcs3 and the third N-pole center position Pcn3, opposite to the upper layer coil 16. In detail, the outer winding Wbo is arranged to extend on both sides in the circumferential direction with a third shift position P3, which is shifted by a predetermined angle in the second circumferential direction Dc2 from the third S-pole center position Pcs3, as a center. In addition, the inner winding Wbi is arranged to extend on both sides in the circumferential direction with a fourth shift position P4, which is shifted by a predetermined angle in the second circumferential direction Dc2 from the third N-pole center position Pcn3, as a center. As a result, the circumferential position of the connection line Wfc of the upper layer conductor Wf and the circumferential position of the connection line Wbc of the lower layer conductor Wb are arranged to be staggered in the circumferential direction, as shown in FIG. 2. The above-mentioned predetermined angle of the lower layer coil 17 may be set according to the maximum number of the windings Wbo and Wbi. The above-mentioned predetermined angle of the upper layer coil 16 may be the same as the above-mentioned predetermined angle of the lower layer coil 17, or may be different.

[0080] The numbers of windings Wfo, Wfi, Wbo, Wbi in the circumferential direction of each of the outer circumferential parts 16o, 17o and the inner circumferential parts 16i, 17i are set, for example, to satisfy the relationship of the numbers shown in the graph of Fig. 6. Fig. 6 is a graph that specifies the number m of windings Wfo, Wfi, Wbo, Wbi in each of the parts 16o, 16i, 17o, 17i in the circumferential direction.

[0081] In the graph of FIG. 6, the horizontal axis corresponds to the circumferential angle shown in FIG. 5. The vertical axis on the left side corresponds to the number m of the windings Wfo, Wfi, Wbo, and Wbi. On the vertical axis on the left side, the "(S)" side corresponds to the number m of the windings Wfi and Wbo that form the S pole, and the "(N)" side corresponds to the number m of the windings Wfo and Wbi that form the N pole. For convenience, in FIG. 6, the outer windings Wfo and Wbo are shown with thicker lines than the inner windings Wfi and Wbi. The windings Wfo and Wfi of the upper conductor Wf are shown with solid lines, and the windings Wbo and Wbi of the lower conductor Wb are shown with dashed lines.

[0082] 6, the vertical axis on the right side corresponds to the number of turns M of the S pole and N pole formed in detection coil 13 by the interaction of portions 16o, 16i, 17o, and 17i. On the vertical axis on the right side, the "(S)" side corresponds to the number of turns M of the S pole, and the "(N)" side corresponds to the number of turns M of the N pole.

[0083] 6, the number m of the inner winding Wfi of the upper layer conductor Wf and the outer winding Wbo of the lower layer conductor Wb is set to a maximum value (here, 5) near 180°, i.e., near the third S-pole central position Pcs3. The number m decreases as it moves away from the 180° position, and is set to a minimum value (here, 0) near 0° (360°).

[0084] Conversely, the outer winding Wfo of the upper layer conductor Wf and the inner winding Wbi of the lower layer conductor Wb are set so that the number m is a maximum value (here, 5) near 0° (360°), i.e., near the third N-pole central position Pcn3. Also, the number m decreases as it moves away from the 0° position, and is set so that the number m is a minimum value (here, 0) near 180°.

[0085] By setting the number m of each of the windings Wfo, Wfi, Wbo, and Wbi as described above, a cosine-shaped change in the number of turns M, which takes one cycle per circumferential revolution, is obtained in the detection coil 13, as shown by the dotted waveform. In other words, taking the 90° position, which is the boundary position between the S pole and the N pole of the detection coil 13, as the starting point, the detection coil 13 obtains a sine-shaped change in the number of turns, which takes one cycle between the S pole and the N pole.

[0086] As a result, when a current flows through the detection coil 13, a magnetic flux distribution according to the change in the number of turns of the detection coil 13, i.e., a sinusoidal magnetic flux distribution, is formed, resulting in a magnetic flux distribution with little distortion. In other words, the number m of each of the windings Wfo, Wfi, Wbo, and Wbi is set so that the dotted waveform, which is a composite wave of the lines (waveforms) of the windings Wfo, Wfi, Wbo, and Wbi, approximates a sine waveform with one cycle per circumferential revolution (between the S pole and the N pole), thereby giving the detection coil 13 magnetic properties that form a sinusoidal magnetic flux distribution with little distortion between the S pole and the N pole.

[0087] In this embodiment, since each of the connection lines Wfc, Wbc extends in the radial direction as described above, the step positions of the waveforms representing each of the windings Wfo, Wfi, Wbo, Wbi correspond to the positions of each of the connection lines Wfc, Wbc. The graph in Fig. 6 thus also shows the positions of each of the connection lines Wfc, Wbc, and can be said to be a graph that defines the positional relationship of the multiple connection lines Wfc, Wbc in the circumferential direction.

[0088] The detection coil 13 has multiple connection wires Wfc, Wbc set (routed) so as to pass through circumferential positions that form a sinusoidal magnetic flux distribution that forms one cycle between the south pole and the north pole, i.e., the step positions of the waveform of each winding Wfo, Wfi, Wbo, Wbi shown in Figure 6. This results in a change in the number of turns of the waveform shown by dotted lines in Figure 6, and suppresses distortion of the magnetic flux distribution when current flows.

[0089] In addition, the number of turns M of the detection coil 13 changes at the step position, and the magnitude of the magnetic flux changes according to the change in the number of turns M, so that the step position can also be referred to as a magnetic flux change position. Even if the connection lines Wfc and Wbc are extended at an incline with respect to the radial direction, the detection coil 13 is arranged so that the connection lines Wfc and Wbc pass through the magnetic flux change position, thereby suppressing distortion of the magnetic flux distribution when a current flows. The magnetic flux change position may be set according to the circumferential length between a pair of magnetic poles and the maximum value of the number m of the windings Wfo, Wfi, Wbo, and Wbi. When the connection lines Wfc and Wbc are extended at an incline with respect to the radial direction, the connection lines Wfc and Wbc are preferably arranged so as to pass through the magnetic flux change position and to make the step-like step in FIG. 6 into a slope. This allows the dot-painted waveform, which is a composite wave of the waveforms of the windings Wfo, Wfi, Wbo, and Wbi, to change more smoothly. Therefore, a waveform that more closely resembles a sine waveform can be obtained, suppressing distortion of the magnetic flux distribution (especially sudden changes in the magnetic flux).

[0090] Furthermore, in this embodiment, due to the arrangement (inclination) relationship between the upper layer coil 16 and the lower layer coil 17, the inner winding Wfi of the upper layer conductor Wf and the outer winding Wbo of the lower layer conductor Wb are out of phase with each other by the difference between the second shift position P2 and the third shift position P3. The outer winding Wfo of the upper layer conductor Wf and the inner winding Wbi of the lower layer conductor Wb are out of phase with each other by the difference between the first shift position P1 and the fourth shift position P4.

[0091] Therefore, the position (step position, magnetic flux change position) of the connection line Wfc of the upper layer conductor Wf and the position (step position, magnetic flux change position) of the connection line Wbc of the lower layer conductor Wb are shifted from each other by the above-mentioned phase difference. In this way, since the circumferential position through which the connection line Wfc of the upper layer conductor Wf passes is shifted from the circumferential position through which the connection line Wbc of the lower layer conductor Wb passes, the steps of the dotted waveform become finer. Therefore, a waveform that is more approximating a sine waveform is obtained, and distortion of the magnetic flux distribution (especially sudden changes in magnetic flux) is suppressed.

[0092] [4. Actions and Effects] (1) In the resolver 1 described above, each of the two excitation coils 11, 12 arranged on the first substrate 21 has a first portion 11f, 12f and a second portion 11b, 12b as a portion forming one magnetic pole. The first portions 11f, 12f are arranged on a first upper layer Lf1 of the first substrate 21. The second portions 11b, 12b are arranged on a layer (first lower layer Lb1) different from the first upper layer Lf1 of the first substrate 21, and are stacked with the first portions 12f, 11f of the coils 12, 11 of a different phase from the coils 11, 12 having the portions 11b, 12b.

[0093] In this way, by arranging the two excitation coils 11, 12 overlapping in the axial direction, each of the two excitation coils 11, 12 can be widely deployed in the circumferential direction on the first substrate 21, and any magnetic flux distribution with little distortion (particularly, a magnetic flux distribution with few places where magnetic coupling is lost) can be formed in each excitation coil 11, 12. Furthermore, at least in the first portions 11f, 12f, the axial positional relationship (axial distance) between the two excitation coils 11, 12 and the detection coil 13 becomes equal, so that the impedance difference between the two excitation coils 11, 12 can be reduced.

[0094] Furthermore, in the above-described resolver 1, the first parts 11f, 12f and the second parts 11b, 12b forming one magnetic pole each have a substantially closed shape formed by winding the conductors W11, W12 around the center position Pc of each magnetic pole, and are electrically connected to each other via single through holes 11h, 12h. This makes it possible to suppress the wiring resistance difference between the two excitation coils 11, 12 compared to a configuration in which the first parts 11f, 12f and the second parts 11b, 12b are connected via multiple through holes. In addition, since it is not necessary to distort the shape of each excitation coil 11, 12 to provide multiple through holes, the distortion of the magnetic flux distribution is also suppressed. Therefore, the detection accuracy of the resolver 1 can be improved.

[0095] (2) The first portions 11f, 12f and the second portions 11b, 12b are formed by the conductor wires W11, W12 that are continuously arranged in the layers Lf1, Lf2, respectively. This makes it possible to form magnetic poles on the inner side of the windings of the conductor wires W11, W12 with a simple configuration.

[0096] (3) In the above-described resolver 1, the first portions 11f, 12f and the second portions 11b, 12b are wound so that the number of turns M decreases as the portion moves away from the center position Pc of each magnetic pole. This allows a magnetic flux distribution with a peak at the center position Pc of the magnetic pole to be obtained with a simple configuration, thereby suppressing distortion of the magnetic flux distribution (especially abrupt changes in the magnetic flux).

[0097] (4) In the above-described resolver 1, the first substrate 21 includes two layers, a first upper layer Lf1 and a first lower layer Lb1, the first portions 11f, 12f are disposed on the first upper layer Lf1, and the second portions 11b, 12b are disposed on the first lower layer Lb1. This allows the axial positional relationship (axial distance) between the two excitation coils 11, 12 and the detection coil 13 to be equal in both the first portions 12f, 11f and the second portions 11b, 12b, and therefore the impedance difference between the two excitation coils 11, 12 can be reduced.

[0098] (5) Regarding the radial widths of the first portions 11f, 12f and the second portions 11b, 12b which form one magnetic pole, if the radial width of the first portions 11f, 12f is set to be smaller than the radial width of the second portions 11b, 12b, the impedance difference between the first portions 11f, 12f and the second portions 11b, 12b caused by the difference in the axial positions of each layer Lf1, Lb1 can be suppressed.

[0099] (6) Furthermore, with regard to the number of turns of the first portion 11f, 12f and the second portion 11b, 12b which form one magnetic pole, if the number of turns of the first portion 11f, 12f is set to be less than the number of turns of the second portion 11b, 12b, the impedance difference between the first portion 11f, 12f and the second portion 11b, 12b caused by the difference in the axial position of each layer Lf1, Lb1 can be suppressed.

[0100] (7) The above-described resolver 1 is provided with a detection coil 13 arranged to face the two excitation coils 11, 12. The detection coil 13 has an upper layer coil 16 arranged on the second upper layer Lf2 of the second substrate 31 and a lower layer coil 17 arranged on the second lower layer Lb2. The upper layer coil 16 and the lower layer coil 17 are formed of conductor wires Wf, Wb wound in different circumferential directions, and have outer circumferential portions 16o, 17o and inner circumferential portions 16i, 17i. When a current flows in the detection coil 13, magnetic poles of different orientations are formed between the upper layer outer circumferential portion 16o and the lower layer inner circumferential portion 17i, and between the upper layer inner circumferential portion 16i and the lower layer outer circumferential portion 17o. Moreover, each of the outer peripheral portion 16o, 17o and the inner peripheral portion 16i, 17i of the detection coil 13 is formed of a plurality of windings Wfo, Wfi, Wbo, Wbi extending in both circumferential directions with respect to the center position Pcs3, Pcn3 of each magnetic pole as a reference, and the number of windings Wfo, Wfi, Wbo, Wbi is set to decrease the farther away from the center position Pcs3, Pcn3 of each magnetic pole. This allows the detection coil 13 to have magnetic characteristics that form a magnetic flux distribution with little distortion that peaks at the center positions Pcs3, Pcn3 of the magnetic poles for each of the S and N poles.

[0101] The resolver 1 described above is configured by combining two excitation coils 11 and 12 with little distortion of the magnetic flux distribution and suppressed impedance difference, and a detection coil 13 with magnetic properties that form a magnetic flux distribution with little distortion, so that when an AC signal is input from the signal processing circuit 4, a change in interlinkage magnetic flux (change in induced voltage) according to the rotation angle of the rotor 3 is obtained on the detection coil 13 side. As a result, an appropriate detection signal according to the rotation angle of the rotor 3 can be obtained, and the detection accuracy of the resolver 1 can be improved.

[0102] [5. Modifications] The configuration of the resolver 1 described above is an example, and is not limited to the above configuration. In the above-mentioned resolver 1, a resolver with a shaft multiplier angle of 1X has been exemplified, but the resolver may have a shaft multiplier angle of kX (k is a natural number of 2 or more). In other words, the "two-phase coil" described in the claims may be a coil with a shaft multiplier angle of kX that forms k magnetic pole pairs, rather than a coil with a shaft multiplier angle of 1X that forms one magnetic pole pair.

[0103] FIG. 7 is a diagram showing a configuration example in which two excitation coils 11', 12' of a resolver have an axial multiplier angle of 2X forming two magnetic pole pairs as a modified example. In the following description, the same components as those described in the embodiment are given the same reference numerals, and the description of the components and effects is omitted. Also, components corresponding to those described in the embodiment are given a prime (') after the reference numerals of the embodiment, and detailed description is omitted. In FIG. 7, as in FIG. 3, the sine excitation coil 11' is shown by a solid line, and the cosine excitation coil 12' is shown by a dashed line.

[0104] When the two excitation coils 11', 12' have an axial multiplier angle of 2X, the sine excitation coil 11' forms a total of four magnetic poles, two S poles and two N poles, and the cosine excitation coil 12' forms a total of four magnetic poles, two S poles and two N poles. For this reason, on the first substrate 21, as shown in Fig. 7, four first center positions Pc1' of the sine excitation coil 11' and four second center positions Pc2' of the cosine excitation coil 12' are set, and these positions Pc1', Pc2' are alternately arranged with a phase difference of 45°.

[0105] Each of the excitation coils 11', 12' has four first portions 11f', 12f' and four second portions 11b', 12b' as portions forming four magnetic poles. The four first portions 11f' of the sine excitation coil 11' are disposed on the first upper layer Lf1 and extend in the first circumferential direction Dc1 with reference to each of the four first central positions Pc1'. The four second portions 11b' of the sine excitation coil 11' are disposed on the first lower layer Lb1 and extend in the second circumferential direction Dc2 with reference to each of the four first central positions Pc1', and are stacked on the four first portions 12f' of the cosine excitation coil 12'. Each of the first portion 11f' and the second portion 11b' that form each magnetic pole of the sine excitation coil 11' has a substantially closed shape formed by winding a conductor W11' around a first central position Pc1', and is electrically connected via a single through hole 11h' provided in the vicinity of the first central position Pc1'.

[0106] Similarly, the four first portions 12f' of the cosine excitation coil 12' are arranged on the first upper layer Lf1 and extend in the first circumferential direction Dc1 with respect to the four second central positions Pc2'. The four second portions 12b' of the cosine excitation coil 12' are arranged on the first lower layer Lb1 and extend in the second circumferential direction Dc2 with respect to the four second central positions Pc2', and are stacked on the four first portions 11f' of the sine excitation coil 11'. The first portions 12f' and the second portions 12b' forming the magnetic poles of the cosine excitation coil 12' each have a substantially closed shape formed by winding a conductor W12' around the second central position Pc2', and are electrically connected via a single through hole 12h' provided in the vicinity of the second central position Pc2'.

[0107] In this way, even if the two excitation coils 11', 12' have an axial multiplication angle of 2X, the first portion 11f', 12f' and the second portion 11b', 12b' forming one magnetic pole of each excitation coil 11', 12' are provided in different layers Lf1, Lb1 and extend in different circumferential directions based on the center positions Pc1', Pc2' of the magnetic pole, so that the impedance difference can be suppressed. Also, the second portion 11b', 12b' of each excitation coil 11', 12' is laminated on the first portion 12f', 11f' of the excitation coil 12', 11' of a different phase from the excitation coil 11', 12', so that an arbitrary magnetic flux distribution with little distortion (particularly, a magnetic flux distribution with few places where magnetic coupling is lost) can be obtained. In addition, the first portions 11f', 12f' and the second portions 11b', 12b', which form one magnetic pole, each have an approximately closed shape around their respective central positions Pc1', Pc2' and are electrically connected to each other via single through holes 11h', 12h', thereby suppressing the difference in wiring resistance between the two excitation coils 11', 12'.

[0108] In the configuration shown in FIG. 7, a sine wave-shaped magnetic flux distribution with two periods per revolution in the circumferential direction is formed in the sine excitation coil 11', and a cosine wave-shaped magnetic flux distribution with two periods per revolution in the circumferential direction is formed in the cosine excitation coil 12'.

[0109] [6.Other] The first substrate 21 on which the two excitation coils 11, 12, 11', 12' are arranged may have three or more layers stacked in the axial direction instead of a two-layer structure. In this case, one of the three or more layers may be a common layer, and both of the first portions 11f, 12f, 11f', 12f' of the two excitation coils 11, 12, 11', 12' may be arranged on the common layer. In addition, the second portions 11b, 12b, 11b', 12b' of the two excitation coils 11, 12, 11', 12' may be arranged on at least another layer other than the common layer, and may not be arranged on the same layer.

[0110] A well-known detection coil configuration may be applied to the detection coil provided in the resolver 1, instead of the configuration of the detection coil 13 described above. In addition, the second substrate 31 on which the detection coil is provided does not have to have a two-layer structure, may have a single-layer structure, or may have three or more layers.

[0111] The "two-phase coil" recited in the claims may be provided on the rotor 3 instead of the stator 2. The "two-phase coil" recited in the claims may be a detection coil, not limited to an excitation coil. The "resolver" recited in the claims may be a one-input two-output type resolver. The "resolver" recited in the claims may be one in which no coil is provided on the rotor (a so-called inductive sensor). In the case of this resolver, both the excitation coil and the detection coil may be provided on the stator, and a conductor that generates a demagnetizing field in a direction that cancels the magnetic field of the excitation coil with a magnitude according to the rotation angle may be provided on the rotor. The "two-phase coil" recited in the claims may be applied as one of the excitation coil and the detection coil of such a resolver. [Explanation of symbols]

[0112] 1 Resolver 2 Stator 3 Rotor 11,11' Sine excitation coil (two-phase coil) 11b,11b′ Second part 11f,11f′ First part 11h,11h' through hole 12,12' Cosine excitation coil (two-phase coil) 12b,12b′ Second part 12f,12f′ First part 12h,12h′ through hole 13 Detection coil (opposing coil) 16 Upper coil (first coil) 16i Upper inner periphery (inner periphery) 16o Upper outer periphery (outer periphery) 17 Lower coil (second coil) 17i Lower inner periphery (inner periphery) 17o Lower layer outer periphery (outer periphery) 21 First board 31 Second board Dc1 First circumferential direction (first direction) Dc2 Second circumferential direction (second direction) Lb1 First lower layer (other layers excluding the common layer, lower layer) Lb2 Second lower layer (second layer) Lf1 First upper layer (common layer, upper layer) Lf2 2nd upper layer (1st layer) m Number M Number of Volumes W11,W11′,W12,W12′ Conductor (first conductor) W13 Conductor (second conductor) Wbi inner winding (winding) Wbo Outer winding (winding) Wfi inner winding (winding) Wfo Outer Winding (Winding)

Claims

1. A resolver that detects a rotation angle of a rotor relative to a stator, a sheet-like first substrate provided on one of the stator and the rotor and having a plurality of layers stacked in a rotation axis direction of the rotor; a sheet-like two-phase coil provided on the first substrate and configured to transmit AC signals whose electrical phases differ from each other by 90 degrees; Each of the coils of the two phases has, as a portion forming one magnetic pole, a first portion extending in a first circumferential direction with a center of the magnetic pole as a reference in one common layer of the plurality of layers, and a second portion extending in a second direction opposite to the first direction with a center of the magnetic pole as a reference in the other layer of the plurality of layers other than the common layer and being stacked on the first portion of the coil of a different phase from the coil, Each of the first and second portions has a substantially closed shape formed by winding a first conductive wire around the center of the magnetic pole, and is electrically connected to each other via a single through hole. A resolver comprising:

2. Each of the first portion and the second portion is formed by the first conductive wire that is continuously routed in the common layer and each of the other layers.

2. The resolver according to claim 1 ,

3. Each of the first and second portions is wound such that the number of turns decreases with distance from the center of the magnetic pole.

2. The resolver according to claim 1 ,

4. the plurality of layers includes an upper layer as the common layer, and a lower layer located on a side farther away from the other of the stator and the rotor than the upper layer, The first portion is disposed on the upper layer, The second portion is disposed on the lower layer. A resolver according to any one of claims 1 to 3.

5. The first portion has a smaller radial width than the second portion.

5. The resolver according to claim 4 .

6. The first portion has fewer turns than the second portion.

5. The resolver according to claim 4 .

7. a sheet-like second substrate provided on the other of the stator and the rotor; a sheet-shaped opposing coil provided on the second substrate and arranged to face the two-phase coil; the second substrate has a first layer and a second layer stacked in the rotation axis direction, the opposing coil includes a first coil having a substantially annular shape formed by the second conducting wire wound in the first direction in the first layer, and a second coil having a substantially annular shape formed by the second conducting wire wound in the second direction in the second layer, Each of the first coil and the second coil has an outer circumferential portion extending in a circumferential direction and an inner circumferential portion extending in the circumferential direction radially inward from the outer circumferential portion, the opposing coils form magnetic poles in different directions between the outer circumferential portion of the first coil and the inner circumferential portion of the second coil, and between the inner circumferential portion of the first coil and the outer circumferential portion of the second coil, Each of the outer peripheral portion and the inner peripheral portion is formed by a plurality of windings of the second conductor that extend in the first direction and the second direction with respect to a center of a magnetic pole formed by each of the outer peripheral portion and the inner peripheral portion, and the number of the windings decreases as the distance from the center of the magnetic pole increases.

4. The resolver according to claim 3 .