Resolver stator and resolver

Abstract

This resolver stator (2), which is provided to a resolver (1) that detects the rotation angle of a resolver rotor (3), comprises: a sheet-shaped substrate (21); a first coil (11, 12) that is provided to the substrate (21) and that receives input of an input signal which is generated in an external device (4); a second coil (15) that is provided to the substrate (21) and that outputs an output signal to the external device (4); a magnetic core (22) that is disposed so as to overlap the substrate (21) in the axial direction and that is disposed so as to be opposite from the first coil (11, 12) and a second coil (15) in the axial direction; and a ground pattern (7) that grounds the core (22) to the external device (4).

Description

Resolver stator and resolver

[0001] The present invention relates to a resolver stator and a resolver including the resolver stator.

[0002] Conventionally, various methods have been proposed for improving the signal-to-noise ratio (S / N ratio) of a sheet-type resolver having a resolver stator and a resolver rotor with a sheet-shaped coil (also called a "sheet coil"). For example, Patent Document 1 (Patent Document 1) discloses a resolver attached to a motor, which includes a resolver rotor including a rotor substrate made of a nonmagnetic conductive material, a sheet coil formed on the rotor substrate, and a magnetic core disposed between the rotor substrate and the sheet coil. Patent Document 1 claims that shielding the sheet coil with a rotor substrate made of a nonmagnetic conductive material can eliminate the effects of the motor's alternating magnetic field. Furthermore, it claims that the magnetic core can prevent the magnetic flux of the sheet coil from being canceled out by the rotor substrate made of a nonmagnetic conductive material, thereby improving the S / N ratio.

[0003] JP 2011-226907 A

[0004] In a resolver such as that disclosed in Patent Document 1, parasitic capacitance can occur between the seat coil and the magnetic core. Here, parasitic capacitance refers to capacitance (capacitor component) that exists parasitically inside an electronic component or electronic circuit due to the physical structure, regardless of the design intent. In a resolver such as that disclosed in Patent Document 1, noise can propagate to the seat coil through such parasitic capacitance, resulting in a decrease in the S / N ratio.

[0005] The resolver stator and resolver of the present invention have been devised in view of the above-mentioned problems, and one of the objects thereof is to improve the S / N ratio and the detection accuracy of the resolver. However, in addition to this object, another object of the present invention is to achieve effects that cannot be obtained by conventional techniques, which are derived from the configurations shown in the below-described embodiments of the invention.

[0006] The disclosed resolver stator and resolver can be realized as the following disclosed aspects (application examples), which solve at least part of the above-mentioned problems.

[0007] The disclosed resolver stator is a resolver stator provided in a resolver that detects the rotation angle of a resolver rotor, and includes a sheet-like substrate, a first coil provided on the substrate and receiving an input signal generated by an external device, a second coil provided on the substrate and outputting an output signal to the external device, a magnetic core that is arranged axially overlapping the substrate and axially facing each of the first coil and the second coil, and a grounding pattern that grounds the core to the external device.

[0008] The disclosed resolver includes the resolver stator according to the above aspect, and a resolver rotor disposed axially opposite the resolver stator.

[0009] According to the disclosed resolver stator and resolver, the S / N ratio can be improved, and the detection accuracy of the resolver can be improved.

[0010] 1 is a perspective view showing a resolver to which a resolver stator according to an embodiment of the present invention is applied, cut in an axial direction and exploded;

[0011] A resolver stator and a resolver according to an embodiment will be described with reference to the drawings. The following embodiment is merely an example, and is not intended to exclude various modifications and applications of techniques not explicitly described in the following embodiment. The configurations of the present embodiment can be modified in various ways without departing from the spirit thereof.

[0012] The resolver of the embodiment is a detector (sensor) that detects the rotation angle of a resolver rotor (hereinafter also simply referred to as "rotor") that rotates about a rotation axis C relative to a resolver stator (hereinafter also simply referred to as "stator"). The resolver stator of the embodiment is a stator included in such a resolver. In the following description, the direction in which the rotation axis C extends (rotation axis direction) is defined as the axial direction, and the direction perpendicular to the axial direction, away from the rotation axis C and toward the rotation axis C, is defined as the radial direction. In addition, in the radial direction, the side of the rotation axis C is defined as the radially inner side, and the opposite side (the side away from the rotation axis C) is defined as the radially outer side. The direction perpendicular to the axial direction and going around the rotation axis C is defined as the circumferential direction.

[0013] [1. Configuration] Fig. 1 is an axially cut and exploded perspective view of a resolver 1 to which a stator 2 (resolver stator) according to this embodiment is applied, and Fig. 2 is a schematic diagram showing the configuration of the resolver 1. The resolver 1 is applied, for example, as a rotation angle detection device for a servo motor (not shown). As shown in Figs. 1 and 2, the resolver 1 includes a stator 2 and a rotor 3 (resolver rotor). The rotor 3 is disposed with a small gap from the stator 2 in a first axial direction D1. Hereinafter, the axial direction opposite to the first direction D1 will be referred to as a second direction D2.

[0014] As shown in Fig. 1, the stator 2 and the rotor 3 each have a sheet-shaped substrate 21, 31. As shown in Fig. 2, a plurality of coils 11 to 15 (sheet coils) are formed (printed) on each of the substrates 21, 31. In other words, the resolver 1 is a sheet-type resolver having a plurality of sheet coils 11 to 15. By using sheet coils in this way, it is possible to reduce the thickness of each of the coils 11 to 15, and ultimately to reduce the thickness of the resolver 1.

[0015] In this embodiment, the resolver 1 is a two-input, one-output resolver, and has five coils: two excitation coils 11 and 12 (first coils), a detection coil 13, a transmission coil 14, and a reception coil 15 (second coil). Of the five coils, two excitation coils 11 and 12 and the reception coil 15 are provided on the stator 2 and electrically connected to a signal processing circuit 4 (external device). An input signal generated by the signal processing circuit 4 is input to the excitation coils 11 and 12. The reception coil 15 outputs an output signal to the signal processing circuit 4.

[0016] The stator 2 is a component fixed to a casing (not shown) of a device to which the resolver 1 is applied (for example, a servo motor or a device to which a servo motor is attached). As shown in Figures 1 and 2, the stator 2 includes a first substrate 21, excitation coils 11 and 12, a receiving coil 15, and a core 22 arranged to overlap the first substrate 21 in the axial direction. The stator 2 of this embodiment further includes a metal plate 23 arranged to overlap the core 22 in the axial direction.

[0017] The first substrate 21 is a thin sheet made of a non-conductive resin (e.g., polyimide). As shown in Fig. 1, the first substrate 21 has an annular substrate portion 21A that is unfolded around the rotation axis C, and a rectangular connector portion 21B that protrudes radially outward from a part of the outer periphery of the substrate portion 21A.

[0018] The excitation coils 11, 12 and the receiver coil 15 shown in Fig. 2 are formed on the substrate section 21A. As shown in Fig. 2, the substrate section 21A has a thickness in the axial direction that is greater than the excitation coils 11, 12 and the receiver coil 15. The excitation coils 11, 12 and the receiver coil 15 are formed on the substrate section 21A without being exposed in the axial direction (i.e., so as to be built into the substrate section 21A). In other words, both sides of the excitation coils 11, 12 and the receiver coil 15 in the axial direction are covered with a polyimide sheet that forms part of the substrate section 21A. Note that each of the coils 11, 12, 15 is made of, for example, copper foil.

[0019] The connector portion 21B is a portion where the signal lines of the excitation coils 11, 12 and the receiving coil 15 are routed, and as shown in Fig. 1, its radially outer end is connected to the connector portion 4A of the signal processing circuit 4. This electrically connects the excitation coils 11, 12 and the receiving coil 15 to the signal processing circuit 4. The signal lines of the coils 11, 12, and 15 are made of, for example, copper foil.

[0020] The shapes and radial and circumferential arrangements of the coils 11, 12, and 15 on the substrate unit 21A are not particularly limited. In the present embodiment, as an example, as shown in FIG. 2, the receiving coil 15 is arranged radially inward with a gap between them and the exciting coils 11 and 12. The exciting coils 11 and 12 are formed, for example, in a first region R1 (see FIG. 1) of an annular shape centered on the rotation axis C on the substrate unit 21A. The receiving coil 15 is formed in a second region R2 (see FIG. 1) of an annular shape centered on the rotation axis C, radially inward of the first region R1. Note that in the first region R1, the two exciting coils 11 and 12 may be arranged side by side in the radial direction as shown in FIG. 2, or may be arranged at the same radial position so as to overlap in the axial direction, or so as to be staggered in the circumferential direction.

[0021] In this embodiment, the excitation coils 11 and 12 are both multipole coils with an axial multiplier angle of nX, forming n magnetic pole pairs within the first region R1. The value of n, which represents the axial multiplier angle, may be any natural number equal to or greater than 2, and the larger the value of n, the better the angular resolution. Furthermore, the two excitation coils 11 and 12 are provided as a sine excitation coil 11 and a cosine excitation coil 12.

[0022] The core 22 is a magnetic member that is stacked on the first substrate 21 on the second direction D2 side (the side away from the rotor 3) and is arranged axially opposite each of the excitation coils 11 and 12 and the receiving coil 15. Examples of magnetic materials used for the core 22 include an electromagnetic steel plate, an amorphous material, and a magnetic sheet containing ferrite powder.

[0023] The stator 2 of this embodiment includes, as cores 22, a first core 22A disposed adjacent to the excitation coils 11 and 12 in the axial direction and a second core 22B disposed adjacent to the receiver coil 15 in the axial direction. As shown in FIG. 1 , the first core 22A is, for example, an annular shape having substantially the same diameter as the first region R1, and as shown in FIG. 2 , is disposed between the excitation coils 11 and 12 with a polyimide sheet (insulator, part of the substrate portion 21A) interposed therebetween. Similarly, as shown in FIG. 1 , the second core 22B is, for example, an annular shape having substantially the same diameter as the second region R2, and as shown in FIG. 2 , is disposed between the receiver coil 15 with a polyimide sheet interposed therebetween. The core 22 may be provided with a portion connecting a circumferential portion of the first core 22A and a circumferential portion of the second core 22B. In other words, the core 22 may be configured as a single member disposed axially facing both the excitation coils 11 and 12 and the receiver coil 15.

[0024] The metal plate 23 is a metal member laminated on the second direction D2 side of the core 22, and has, for example, a plate (sheet) shape that has approximately the same external shape as the substrate portion 21A of the first substrate 21 when viewed in the axial direction and covers the substrate portion 21A from the second direction D2 side. The metal plate 23 may be directly fixed to the core 22 with metal screws or the like (not shown), or may be arranged via an adhesive sheet (insulating material) (not shown).

[0025] The metal plate 23 may be, for example, a sheet of non-magnetic aluminum material. However, the metal plate 23 does not have to be a non-magnetic material and may be, for example, an iron plate. The provision of the metal plate 23 increases the rigidity of the stator 2 and reduces distortion of its shape compared to a stator configured only with the thin sheet-like first substrate 21 and core 22. Furthermore, when fixing the stator 2 to another structure such as a case, operations such as screwing, crimping, and welding are facilitated. If the metal plate 23 is made of a non-magnetic material, it is less susceptible to the effects of leakage magnetic flux (noise due to external magnetic flux) from a magnetic device such as a motor. The shielding effect of the metal plate 23 as a shield against external noise (electromagnetic waves) is enhanced by using a metal material with low electrical resistance. For example, copper may be used.

[0026] The rotor 3 is a component that is rotatably supported (around the center of rotation) integrally with the rotation axis C relative to the stator 2. As shown in Figures 1 and 2, the rotor 3 includes, for example, a second substrate 31, a detection coil 13, a transmission coil 14, a core 32, and a metal plate 33.

[0027] The second substrate 31 is a thin sheet made of a non-conductive resin (e.g., polyimide) similar to the first substrate 21. The detection coil 13 and the transmission coil 14 shown in FIG. 2 are formed on the second substrate 31. In the second substrate 31, the detection coil 13 and the transmission coil 14 may be covered on both axial sides with a polyimide sheet that forms part of the second substrate 31, similar to the excitation coils 11 and 12 and the reception coil 15 formed on the first substrate 21. For example, as shown in FIG. 1, the second substrate 31 has an annular shape with a diameter equivalent to that of the substrate portion 21A of the first substrate 21 when viewed in the axial direction.

[0028] On the second substrate 31, the detection coil 13 is disposed axially opposite the excitation coils 11 and 12. In this embodiment, the detection coil 13 is provided in an annular third region R3 (see FIG. 1 ) of the second substrate 31, having the same diameter as the first region R1, in correspondence with the positions of the excitation coils 11 and 12. The detection coil 13, like the excitation coils 11 and 12, is a multipole coil having an axial multiplication angle of nX, and forms n magnetic pole pairs within the third region R3.

[0029] The transmitter coil 14 is disposed axially opposite the receiver coil 15 on the second substrate 31. In this embodiment, the transmitter coil 14 is provided in an annular fourth region R4 (see FIG. 1 ) having the same diameter as the second region R2 of the second substrate 31, corresponding to the position of the receiver coil 15. As shown in FIG. 2 , the transmitter coil 14 is electrically connected (connected in series) to the detector coil 13. The detector coil 13 and the transmitter coil 14 are made of, for example, copper foil.

[0030] The core 32 is a magnetic member that is arranged to overlap the second substrate 31 on the first direction D1 side (the side away from the stator 2) and is arranged axially opposite each of the detection coil 13 and the transmission coil 14. The core 32 may be made of the same magnetic material as the core 22 of the stator 2.

[0031] The rotor 3 of this embodiment includes, as the cores 32, a third core 32C arranged opposite the detection coil 13 and a fourth core 32D arranged opposite the transmission coil 14. As shown in FIG. 1 , the third core 32C has an annular shape with, for example, approximately the same diameter as the third region R3, and as shown in FIG. 2 , is disposed axially between the detection coil 13 and the fourth core 32C with a polyimide sheet (insulator, part of the second substrate 31) interposed therebetween. Similarly, as shown in FIG. 1 , the fourth core 32D has an annular shape with, for example, approximately the same diameter as the fourth region R4, and as shown in FIG. 2 , is disposed axially between the detection coil 13 and the fourth core 32C with a polyimide sheet interposed therebetween. Note that the core 32 may be provided with a portion connecting a circumferential portion of the third core 32C and a circumferential portion of the fourth core 32D.

[0032] The metal plate 33 is a member arranged to overlap the core 32 on the first direction D1 side, and for example, has a plate (sheet) shape that has approximately the same outer shape as the second substrate 31 when viewed in the axial direction and covers the second substrate 31 from the first direction D1 side. The metal plate 33 may be, for example, a sheet of non-magnetic aluminum material, similar to the metal plate 23 of the stator 2. Furthermore, similar to the metal plate 23 of the stator 2, the metal plate 33 may be arranged on the core 32 via an adhesive sheet (insulating material) not shown.

[0033] The signal processing circuit 4 is an electric circuit that generates input signals to be input to the excitation coils 11, 12 and converts an output signal output from the receiving coil 15 into a rotation angle (angle information) of the rotor 3 relative to the stator 2, and is provided outside the resolver 1. For example, as shown in Fig. 1, the signal processing circuit 4 may be formed on an annular substrate that is developed around the rotation axis C, at a position different from the stator 2 and rotor 3 in the axial direction. As shown in Fig. 2, the signal processing circuit 4 incorporates a signal generating circuit 5 that generates an input signal and a signal processing circuit 6 that outputs angle information corresponding to the rotation angle based on the output signal.

[0034] In this embodiment, the signal generating circuit 5 inputs amplitude-modulated high-frequency (for example, 100 kHz or higher) AC signals (signals whose signal waveforms include a carrier wave and a modulating wave) as input signals to the excitation coils 11 and 12. More specifically, the signal generating circuit 5 inputs AC signals whose electrical angle phases differ by 90 degrees to the sine excitation coil 11 and the cosine excitation coil 12, respectively. A cosine waveform AC signal is input to the sine excitation coil 11, and a sine waveform AC signal is input to the cosine excitation coil 12.

[0035] When an AC signal is input to the excitation coils 11 and 12, the excitation coils 11 and 12 are excited and generate magnetic flux (see the white arrows in FIG. 2). This magnetic flux interlinks with the detection coil 13 on the rotor 3 side, generating an induced voltage. As a result, a phase-modulated signal (a composite waveform including phase information) is generated in the detection coil 13.

[0036] The signal generated in the detection coil 13 is transmitted to the transmission coil 14 connected in series to the detection coil 13. The transmission coil 14 is thereby excited and generates a magnetic flux (see the black arrows in FIG. 2 ). This magnetic flux interlinks with the reception coil 15 of the stator 2, generating an induced voltage. The waveform of this induced voltage (a composite waveform including phase information) is output as an output signal to the signal processing circuit 6, which converts it into angle information corresponding to the rotation angle and outputs it. In other words, the resolver 1 of this embodiment is a modulated wave resolver that receives an amplitude-modulated AC signal as input and uses it to detect the rotation angle from the phase-modulated signal generated in the detection coil 13.

[0037] In the stator 2 of the resolver 1 described above, the thickness of the polyimide sheet (thickness of the insulator) between the two exciting coils 11 and 12 and the receiving coil 15 and the core 22 can become a parasitic capacitance. Note that the parasitic capacitance here refers to a capacitance (capacitor component) that exists parasitically inside an electronic component or electronic circuit due to a physical structure, regardless of the design intent.

[0038] In the stator 2, a portion of the input signal input to the excitation coils 11 and 12 may be propagated as noise to the receiving coil 15 through the parasitic capacitance. More specifically, as indicated by the lightly dotted arrow A1 in FIG. 2 , the thickness of the polyimide sheet between the excitation coils 11 and 12 and the first core 22A becomes parasitic capacitance, and a current corresponding to a voltage change in the input signal is generated on the first core 22A side through the parasitic capacitance. The current generated on the first core 22A side flows to the second core 22B directly or indirectly via the metal plate 23. Then, as indicated by the darkly dotted arrow A2 in FIG. 2 , the thickness of the polyimide sheet between the second core 22B and the receiving coil 15 becomes parasitic capacitance, and a portion of the input signal is propagated as noise to the receiving coil 15 through the parasitic capacitance.

[0039] As a result, in the receiving coil 15, a part of the input signal propagated through the parasitic capacitance may interfere as noise with the signal received from the transmitting coil 14 (hereinafter referred to as the "received signal"), and a waveform containing noise may be output as an output signal to the signal processing circuit 6. This may reduce the S / N ratio and decrease the detection accuracy of the resolver 1.

[0040] Therefore, the stator 2 is provided with a ground pattern 7 as a configuration for preventing the current flowing through the core 22 via parasitic capacitance from interfering with the receiving coil 15. The ground pattern 7 is a conductor that grounds the core 22 to the signal processing circuit 4 by passing (returning) the current generated in the core 22 to the signal processing circuit 4. Note that the term "ground" used here means determining a reference potential for the core 22, and is not limited to using the earth. The ground pattern 7 is connected to a conductor that serves as the reference potential of the signal processing circuit 4, thereby grounding the core 22 to the signal processing circuit 4.

[0041] The ground pattern 7 of this embodiment grounds the core 22 to the signal processing circuit 4 via the metal plate 23. As shown in Figures 1 and 2, one end of the ground pattern 7 is connected to the metal plate 23, and the other end is connected to the reference potential of the signal processing circuit 4. As shown in Figure 1, the ground pattern 7 may be routed to the connector portion 21B of the first substrate 21 and connected to the signal processing circuit 4 together with the signal lines of the excitation coils 11 and 12 and the receiving coil 15. Alternatively, the ground pattern 7 may be connected to the signal processing circuit 4 via a path separate from the signal lines of the excitation coils 11 and 12 and the receiving coil 15.

[0042] [2. Actions and Effects] (1) The stator 2 and resolver 1 described above are provided with the ground pattern 7. This allows the current generated in the first core 22A through the parasitic capacitance between the excitation coils 11 and 12 (first coil) and the first core 22A to flow to the signal processing circuit 4. This makes it difficult for the current (corresponding to the voltage change of the input signal) generated in the first core 22A to flow to the second core 22B, which is arranged opposite the receiver coil 15 (second coil). This prevents a portion of the input signal from being transmitted to the receiver coil 15 through the parasitic capacitance between the second core 22B and the receiver coil 15. In other words, the current that causes noise can be grounded, thereby reducing the noise contained in the output signal. This improves the S / N ratio and the detection accuracy of the resolver 1.

[0043] In particular, in a sheet-type resolver 1 having coils 11 to 15 formed on sheet-like substrates 21 and 31, it is difficult to ensure a sufficient number of turns for each of the coils 11 to 15. This makes it easy for the magnetic flux of the excitation coils 11 and 12 and the transmission coil 14 to weaken, and the strength of the received signal to weaken. In such a resolver 1, if the influence of noise through parasitic capacitance is eliminated by providing a ground pattern 7 on the stator 2, the S / N ratio can be improved even if the strength of the received signal is weak, and the detection accuracy of the resolver 1 can be improved.

[0044] (2) When the input signal is a high-frequency AC signal of 100 kHz or more, a current corresponding to a voltage change of the input signal is more likely to be generated on the first core 22A side. Therefore, in the resolver 1 to which a high-frequency AC signal is input, by providing the ground pattern 7 on the stator 2, the effect of the ground pattern 7 can be more effectively enjoyed, and the detection accuracy of the resolver 1 can be appropriately improved.

[0045] (3) In the stator 2 described above, the ground pattern 7 is connected to the metal plate 23 and the signal processing circuit 4. Thus, by grounding the core 22 via the metal plate 23 electrically connected to the signal processing circuit 4, the core 22 can be indirectly grounded to the signal processing circuit 4. In particular, when the input signal is a high-frequency AC signal, even if an adhesive sheet (insulating material) is provided between the core 22 and the metal plate 23, parasitic capacitance occurs between the core 22 and the metal plate 23, and a portion of the input signal may be propagated as noise to the receiving coil 15 via the metal plate 23. In such a resolver 1, connecting the ground pattern 7 to the metal plate 23 and the signal processing circuit 4 can further enhance the effect of the ground pattern 7 and appropriately improve the detection accuracy of the resolver 1. Furthermore, since the core 22 can be grounded collectively via the metal plate 23 rather than individually grounding both the first core 22A and the second core 22B, the structure of the stator 2 can be simplified.

[0046] (4) Furthermore, when the excitation coils 11, 12 are multi-pole coils as in the stator 2 described above, the size of each magnetic pole formed within the first region R1 is small. As a result, the magnetic flux of each magnetic pole of the excitation coils 11, 12 is likely to be weak, and the strength of the received signal is likely to be weak. In such a resolver 1, if the ground pattern 7 is provided on the stator 2 to eliminate the influence of noise through parasitic capacitance, the S / N ratio can be improved even if the strength of the received signal is weak, and the detection accuracy of the resolver 1 can be improved.

[0047] [3. Other] The above-described configurations of the stator 2 and resolver 1 are merely examples and are not limited to the above-described configurations. The stator 2 may be any one that includes at least a first coil to which an input signal is input from the signal processing circuit 4, a second coil that outputs an output signal to the signal processing circuit 4, and a sheet-like substrate on which both the first coil and the second coil are formed, and may not be the stator 2 of a two-input, one-output resolver 1. In other words, the resolver 1 does not have to be a two-input, one-output detector.

[0048] The resolver may be, for example, a one-input, two-output detector. In this case, the stator may have one excitation coil as the first coil and two receiving coils as the second coil. Alternatively, if the excitation coil is provided on the rotor side, the stator may have one transmitting coil as the first coil and two detecting coils as the second coil. The resolver may have an excitation coil and a detecting coil provided on the stator, and the rotor may have a conductor that generates a demagnetizing field in a direction that cancels out the magnetic field of the excitation coil, with a magnitude corresponding to the rotation angle. In other words, the resolver rotor may not have a coil.

[0049] The ground pattern 7 may directly ground the core 22 to the signal processing circuit 4. That is, the ground pattern 7 may have one end of a conductor connected to the core 22 and the other end connected to a conductor that serves as a reference potential for the signal processing circuit 4. In this case, the ground pattern 7 preferably grounds both the first core 22A and the second core 22B to the signal processing circuit 4. When the ground pattern 7 directly grounds the core 22 to the signal processing circuit 4, the metal plate 23 may be omitted, or a resin insulating member that serves as the base of the stator 2 may be provided instead of the metal plate 23.

[0050] The "external device" described in the claims may be at least a device that inputs an input signal to the first coil and outputs an output signal from the second coil. The "external device" described in the claims may not be the signal processing circuit 4, but may be, for example, a control device provided outside the resolver 1.

[0051] REFERENCE SIGNS LIST 1 Resolver 2 Stator (resolver stator) 3 Rotor (resolver rotor) 4 Signal processing circuit (external device) 7 Ground pattern 11 Sine excitation coil (excitation coil, first coil) 12 Cosine excitation coil (excitation coil, first coil) 15 Receiving coil (second coil) 21 First substrate (substrate) 22 Core 23 Metal plate

Claims

1. A resolver stator provided in a resolver that detects the rotation angle of a resolver rotor, comprising: a sheet-like substrate; a first coil provided on the substrate and receiving an input signal generated by an external device; a second coil provided on the substrate and outputting an output signal to the external device; a magnetic core that is arranged to overlap with the substrate in the axial direction and to face each of the first coil and the second coil in the axial direction; and a grounding pattern that grounds the core to the external device.

2. The resolver stator according to claim 1, wherein the input signal is a high-frequency AC signal of 100 kHz or more.

3. The resolver stator according to claim 2, further comprising a metal plate arranged to overlap the core in the axial direction, and the ground pattern is connected to the metal plate and the external device.

4. The resolver stator according to claim 3, wherein the first coil or the second coil is a multi-pole coil.

5. A resolver comprising: a resolver stator according to any one of claims 1 to 4; and a resolver rotor arranged axially opposite the resolver stator.

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