Resolver stator and resolver

Abstract

A resolver stator (2) provided in a resolver (1) for detecting the rotation angle of a resolver rotor (3) is provided with: a sheet-like substrate (21); first coils (11, 12) which are provided on the substrate (21) and into which an input signal generated by an external device (4) is input; a second coil (15) that is provided on the substrate (21) and outputs an output signal to an external device (4); a magnetic core (22) which is disposed so as to overlap the substrate (21) in the axial direction, and which is disposed so as to face the first coils (11, 12) and the second coil (15) in the axial direction; and a ground pattern (7) that grounds the core (22) to an external device (4).

Description

Technical Field

[0001] The present application relates to a resolver stator and a resolver having the resolver stator. Background Art

[0002] In the past, various methods for improving the signal-to-noise ratio (S / N ratio) have been proposed in a sheet-type rotary transformer having a rotary transformer stator with a sheet-shaped coil (also called a "sheet coil") and a rotary transformer rotor. For example, Patent Document 1 discloses a rotary transformer rotor installed in a motor, wherein the rotary transformer rotor has a rotor substrate formed of a non-magnetic conductor, a sheet coil formed on the rotor substrate, and a magnetic core arranged between the rotor substrate and the sheet coil. According to Patent Document 1, by shielding the sheet coil with a rotor substrate made of a non-magnetic conductor, the influence of the alternating magnetic field of the motor can be eliminated. In addition, the magnetic core can be used to prevent the magnetic flux of the sheet coil from being offset by the action of the rotor substrate made of a non-magnetic conductor, thereby improving the S / N ratio.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-226907 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the rotary transformer disclosed in Patent Document 1, parasitic capacitance occurs between the sheet coil and the magnetic core. Here, parasitic capacitance refers to capacitance (capacitor component) that exists parasitically due to physical structure inside an electronic component or in an electronic circuit, regardless of the design intent. In the rotary transformer disclosed in Patent Document 1, noise is transmitted to the sheet coil through such parasitic capacitance, which leads to a decrease in the S / N ratio.

[0008] The rotary transformer stator and rotary transformer of the present application are proposed in view of such a problem, and one of its purposes is to improve the S / N ratio and improve the detection accuracy of the rotary transformer. It should be noted that it is not limited to this purpose, and another purpose of the present application is to achieve the effects derived from the various structures shown in the specific embodiments described later and the effects that cannot be obtained by the previous technology.

[0009] Solutions to Solve Problems

[0010] The resolver stator and resolver of the present application can be implemented as the following disclosed aspects (application examples), and solve at least a part of the above-mentioned problems.

[0011] The rotary transformer stator of the present application is a rotary transformer stator possessed by a rotary transformer for detecting the rotation angle of a rotary transformer rotor, and comprises: a sheet-shaped substrate; a first coil, which is arranged on the substrate and is input with an input signal generated by an external device; a second coil, which is arranged on the substrate and outputs an output signal to the external device; a magnetic core, which is arranged to overlap with the substrate in the axial direction and is arranged to be opposite to the first coil and the second coil in the axial direction; and a grounding pattern, which grounds the core to the external device.

[0012] The resolver of the present application includes: the resolver stator according to the above-mentioned aspect; and a resolver rotor disposed to face the resolver stator in the axial direction.

[0013] Effects of the Invention

[0014] According to the resolver stator and the resolver of the present application, the S / N ratio can be improved, and the detection accuracy of the resolver can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a perspective view showing a resolver to which a resolver stator according to the embodiment is applied, cut along the axial direction and exploded.

[0016] Figure 2 It is shown Figure 1 Schematic diagram of the construction of a rotary transformer. DETAILED DESCRIPTION

[0017] The rotary transformer stator and the rotary transformer as embodiments are described with reference to the accompanying drawings. The embodiments shown below are merely illustrative and are not intended to exclude various modifications and technical applications not explicitly shown in the following embodiments. The various structures of the present embodiment can be implemented with various modifications within the scope of their purpose.

[0018] The rotary transformer of the embodiment is a detector (sensor) that detects the rotation angle of the rotary transformer rotor (hereinafter, also referred to as the "rotor") that rotates around the rotation axis C relative to the rotary transformer stator (hereinafter, also referred to as the "stator"). The rotary transformer stator of the embodiment is a stator possessed by such a rotary transformer. 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 orthogonal to the axial direction and away from the rotation axis C and the direction toward the rotation axis C are defined as the radial direction. In addition, in the radial direction, the rotation axis C side is defined as the radial inner side, and the side opposite thereto (the side away from the rotation axis C) is defined as the radial outer side. The direction orthogonal to the axial direction and surrounding the rotation axis C is defined as the circumferential direction.

[0019] [1. Structure]

[0020] Figure 1 1 is a perspective view showing a resolver 1 to which a stator 2 (resolver stator) according to the present embodiment is applied, cut along the axial direction and exploded. Figure 2 1 is a schematic diagram showing the structure of a resolver 1. The resolver 1 is applied, for example, as a rotation angle detection device of a servo motor (not shown). Figure 1 as well as Figure 2 As shown, the resolver 1 includes a stator 2 and a rotor 3 (resolver rotor). The rotor 3 is arranged with a small gap in a first axial direction D1 relative to the stator 2. Hereinafter, the direction opposite to the first axial direction D1 is referred to as a second direction D2.

[0021] The stator 2 and the rotor 3 are respectively as follows Figure 1 As shown in FIG. 1 , the substrates 21 and 31 are provided. Figure 2 As shown, a plurality of coils 11 to 15 (sheet coils) are formed (printed). That is, the resolver 1 is a sheet-type resolver having a plurality of sheet coils 11 to 15. By using sheet coils in this way, the thickness of each coil 11 to 15 can be reduced, and the resolver 1 can be reduced in thickness.

[0022] In the present embodiment, the rotary transformer 1 is a two-input one-output rotary transformer, and has five coils, namely, two excitation coils 11 and 12 (first coils), a detection coil 13, a transmission coil 14, and a reception coil 15 (second coil). Two of the five coils, the excitation coils 11 and 12, and the reception coil 15 are provided on the stator 2, and are electrically connected to the 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.

[0023] The stator 2 is a component fixed to a housing (not shown) of a device (eg, a servo motor or a device on which the servo motor is mounted) to which the resolver 1 is applied. Figure 1 as well as Figure 2 As shown, the stator 2 includes a first substrate 21, field 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.

[0024] The first substrate 21 is a sheet formed of a non-conductive resin (eg, polyimide). Figure 1As shown, it includes an annular base portion 21A extending around the rotation axis C, and a rectangular connector portion 21B protruding radially outward from a portion of the outer peripheral edge of the base portion 21A.

[0025] The substrate portion 21A is formed with Figure 2 The excitation coils 11, 12 and the receiving coil 15 are shown. The substrate portion 21A is as shown Figure 2 As shown in the figure, the excitation coils 11, 12 and the receiving coil 15 have a greater thickness in the axial direction. The excitation coils 11, 12 and the receiving coil 15 are formed on the substrate 21A so as not to be exposed in the axial direction (that is, to be built into the substrate 21A). In other words, both sides of the excitation coils 11, 12 and the receiving coil 15 in the axial direction are covered by a polyimide sheet forming a part of the substrate 21A. It should be noted that each coil 11, 12, 15 uses, for example, copper foil.

[0026] The connector portion 21B is a portion where the signal lines of the excitation coils 11, 12 and the receiving coil 15 are arranged. Figure 1 As shown, the radially outer end is connected to the connector 4A of the signal processing circuit 4. Thus, the exciting coils 11, 12 and the receiving coil 15 are electrically connected to the signal processing circuit 4. The signal lines of the coils 11, 12, 15 are made of copper foil, for example.

[0027] The shape, radial direction, and circumferential arrangement of the coils 11, 12, and 15 in the substrate portion 21A are not particularly limited. Figure 2 As shown in FIG. 1 , the receiving coil 15 is arranged radially inwardly with a gap relative to the excitation coils 11 and 12. The excitation coils 11 and 12 are formed, for example, in a first annular region R1 (see FIG. 1 ) centered on the rotation axis C in the substrate portion 21A. Figure 1 ). In addition, the receiving coil 15 is formed in the annular second region R2 (see FIG. 1 ) which is radially inward of the first region R1 and centered on the rotation axis C. Figure 1 It should be noted that in the first region R1, the two excitation coils 11 and 12 can be as follows Figure 2 Although they are arranged in parallel in the radial direction as shown, they may be arranged at the same radial position so as to overlap in the axial direction or be arranged so as to be staggered in the circumferential direction.

[0028] In the present embodiment, the excitation coils 11 and 12 are both multi-pole coils with an axial angle multiplier of nX, and n magnetic pole pairs are formed in the first region R1. It should be noted that the value of n representing the axial angle multiplier can be a natural number greater than 2, and the larger the value of n, the higher the angular resolution. In addition, as the two excitation coils 11 and 12, a sine excitation coil 11 and a cosine excitation coil 12 are provided.

[0029] 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 to the excitation coils 11, 12 and the receiving coil 15. Examples of the magnetic material used for the core 22 include electromagnetic steel plates, magnetic sheets containing amorphous or ferrite powders, and the like.

[0030] The stator 2 of this embodiment includes 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 receiving coil 15 in the axial direction as the core 22. The first core 22A is as shown in FIG. Figure 1 As shown in FIG. 1 , for example, it is in the shape of a ring having substantially the same diameter as the first region R1, and Figure 2 As shown in FIG. 1 , the second core 22B is arranged with a polyimide sheet (insulator, part of the substrate 21A) interposed between the excitation coils 11 and 12. Figure 1 As shown in FIG. 1 , for example, it is in the shape of a ring having substantially the same diameter as the second region R2, and as shown in FIG. Figure 2 As shown in FIG. 1 , the first core 22A is disposed with a polyimide sheet interposed therebetween with the receiving coil 15. It should be noted that a portion connecting a circumferential portion of the first core 22A with a circumferential portion of the second core 22B may be provided in the core 22. That is, the core 22 may be configured as a member disposed opposite to both the excitation coils 11 and 12 and the receiving coil 15 in the axial direction.

[0031] The metal plate 23 is a metal member stacked on the core 22 on the second direction D2 side, and has a shape substantially the same as the substrate portion 21A of the first substrate 21 when viewed from the axial direction, and is in a plate shape (sheet shape) that covers the substrate portion 21A from the second direction D2 side. The metal plate 23 may be directly fixed to the core 22 by metal screws (not shown) or the like, or may be arranged on the core 22 by means of an adhesive sheet (insulating material) (not shown).

[0032] The metal plate 23 is made of, for example, a sheet of non-magnetic aluminum. However, the metal plate 23 may not be a non-magnetic material, and may be, for example, an iron plate. By providing the metal plate 23, the rigidity of the stator 2 is improved and the deformation of the shape is suppressed compared to the case where the stator 2 is composed only of the thin sheet-shaped first substrate 21 and the core 22. In addition, when the stator 2 is fixed to other structures such as a housing, operations such as threaded fastening, riveting, and welding become easy. When the metal plate 23 is made of a non-magnetic material, it is not easily affected by the leakage magnetic flux from magnetic devices such as motors (noise caused by external magnetic flux). Metal raw materials with low electrical resistance further improve the shielding effect of the metal plate 23 as a shield against external noise (electromagnetic waves). For example, it may also be copper.

[0033] The rotor 3 is a member supported by the stator 2 so as to be rotatable integrally with the rotation axis C (around the center of rotation). Figure 1 as well as Figure 2 As shown, 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 .

[0034] The second substrate 31 is a sheet made of a non-conductive resin (for example, polyimide) similarly to the first substrate 21. Figure 2 The detection coil 13 and the transmission coil 14 are shown. In the second substrate 31, the detection coil 13 and the transmission coil 14, like the excitation coils 11, 12 and the receiving coil 15 formed on the first substrate 21, can be covered on both sides of the axial direction by a polyimide sheet forming a part of the second substrate 31. The second substrate 31 is, for example, Figure 1 As shown, it has an annular shape having the same diameter as the substrate portion 21A of the first substrate 21 when viewed from the axial direction.

[0035] In the second substrate 31, the detection coil 13 and the excitation coils 11 and 12 are arranged opposite to each other in the axial direction. In the present embodiment, the detection coil 13 and the excitation coils 11 and 12 are arranged in the annular third region R3 (see FIG. 1 ) of the second substrate 31 and have the same diameter as the first region R1, corresponding to their positions. Figure 1 ). In addition, the detection coil 13 is a multi-pole coil having an axial angle of nX similarly to the exciting coils 11 and 12, and forms n magnetic pole pairs in the third region R3.

[0036] The transmitting coil 14 is arranged axially opposite to the receiving coil 15 in the second substrate 31. In the present embodiment, the transmitting coil 14 and the receiving coil 15 are arranged in a ring-shaped fourth region R4 (see FIG. 1 ) of the second substrate 31 having the same diameter as the second region R2, corresponding to the positions of the transmitting coil 14 and the receiving coil 15. Figure 1 ). The transmitting coil 14 is as follows Figure 2 As shown, the detection coil 13 is electrically connected (connected in series). Note that the detection coil 13 and the transmission coil 14 are made of, for example, copper foil.

[0037] The core 32 is a magnetic member that is overlapped with the second substrate 31 on the first direction D1 side (the side away from the stator 2 ) and is axially opposed to the detection coil 13 and the transmission coil 14 . The core 32 can be made of the same magnetic material as the core 22 of the stator 2 .

[0038] The rotor 3 of this embodiment includes a third core 32C disposed opposite to the detection coil 13 and a fourth core 32D disposed opposite to the transmission coil 14 as the core 32. The third core 32C is as shown in FIG. Figure 1As shown in FIG. 1 , for example, it is in the shape of a ring having substantially the same diameter as the third region R3, and Figure 2 As shown in FIG. 1 , the fourth core 32D is arranged with a polyimide sheet (insulating material, part of the second substrate 31) interposed between the detection coil 13 in the axial direction. Figure 1 As shown in FIG. 1 , for example, it is in the shape of a ring having substantially the same diameter as that of the fourth region R4, and as Figure 2 As shown, the third core 32C is arranged with a polyimide sheet interposed therebetween in the axial direction from the transmission coil 14. Note that the core 32 may be provided with a portion connecting a portion of the third core 32C in the circumferential direction to a portion of the fourth core 32D in the circumferential direction.

[0039] The metal plate 33 is a member that is overlapped and arranged on the core 32 on the first direction D1 side. For example, when viewed from the axial direction, it has an appearance that is substantially the same as the second substrate 31, and is in a plate shape (sheet shape) that covers the second substrate 31 from the first direction D1 side. For example, the metal plate 33 can be made of a non-magnetic aluminum sheet, similar to the metal plate 23 of the stator 2. In addition, the metal plate 33 can be arranged on the core 32 with the aid of an adhesive sheet (insulating material) not shown, similar to the metal plate 23 of the stator 2.

[0040] The signal processing circuit 4 is a circuit that generates an input signal to the excitation coils 11 and 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. The signal processing circuit 4 may be, for example, Figure 1 As shown in FIG. 1 , a circular substrate is formed at a position different from the stator 2 and the rotor 3 in the axial direction and extending around the rotation axis C. Figure 2 As shown, the signal processing circuit 4 includes 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.

[0041] In the present embodiment, the signal generating circuit 5 inputs an amplitude modulated high frequency (e.g., 100 kHz or higher) AC signal (a signal waveform including a carrier wave and a modulated wave) as an input signal 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. The cosine waveform AC signal is input to the sine excitation coil 11, and the sine waveform AC signal is input to the cosine excitation coil 12.

[0042] When an AC signal is input to the excitation coils 11 and 12, the excitation coils 11 and 12 are excited to generate magnetic flux (refer to Figure 2The magnetic flux interlinks with the detection coil 13 on the rotor 3 side to generate an induced voltage. As a result, a phase-modulated signal (a synthetic waveform containing phase information) is generated in the detection coil 13.

[0043] The signal generated by the detection coil 13 is transmitted to the transmission coil 14 connected in series with the detection coil 13. The transmission coil 14 is excited by this and generates a magnetic flux (see Figure 2 The magnetic flux interlinks with the receiving coil 15 of the stator 2 to generate an induced voltage. The waveform of the induced voltage (composite waveform including phase information) is output to the signal processing circuit 6 as an output signal, and is converted into angle information corresponding to the rotation angle by the signal processing circuit 6 and output. That is, the resolver 1 of the present embodiment is a modulated waveform resolver that detects the rotation angle based on a phase-modulated signal generated in the detection coil 13 using the amplitude-modulated AC signal as input.

[0044] However, in the stator 2 of the rotary transformer 1 as described above, the thickness of the polyimide sheet (thickness of the insulator) between the two excitation coils 11 and 12 and the receiving coil 15 and the core 22 becomes a parasitic capacitor. It should be noted that the parasitic capacitor referred to here refers to the capacitance (capacitor component) that exists parasitically due to the physical structure inside the electronic component or in the electronic circuit regardless of the design intention.

[0045] In the stator 2, part of the input signal input to the excitation coils 11 and 12 is transmitted to the receiving coil 15 as noise through the parasitic capacitance. Figure 2 As shown by the sparsely dotted arrow A1 in the figure, the thickness of the polyimide sheet between the excitation coils 11 and 12 and the first core 22A becomes a parasitic capacitor, and a current corresponding to the voltage change of the input signal is generated on the first core 22A side through the parasitic capacitor. The current generated on the first core 22A side flows directly or indirectly to the second core 22B via the metal plate 23. Figure 2 As indicated by the densely dotted arrow A2 , the thickness of the polyimide sheet between the second core 22B and the receiving coil 15 becomes a parasitic capacitance, and a part of the input signal is transmitted to the receiving coil 15 as noise through the parasitic capacitance.

[0046] As a result, in the receiving coil 15, a part of the input signal transmitted through the parasitic capacitance interferes with the signal received from the transmitting coil 14 (hereinafter referred to as the "received signal") as noise, and a waveform including noise is output as an output signal to the signal processing circuit 6. As a result, the S / N ratio is reduced, and the detection accuracy of the resolver 1 is reduced.

[0047] Therefore, the stator 2 is provided with a ground pattern 7 as a structure for preventing the current flowing to the core 22 through the 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 causing the current generated in the core 22 to flow (return) to the signal processing circuit 4. It should be noted that the grounding mentioned here refers to a reference for determining the potential of the core 22, and is not limited to using the earth. The ground pattern 7 is connected to the conductor that becomes the reference potential of the signal processing circuit 4, thereby grounding the core 22 to the signal processing circuit 4.

[0048] The ground pattern 7 of this embodiment grounds the core 22 to the signal processing circuit 4 via the metal plate 23. The ground pattern 7 is as shown in FIG. Figure 1 as well as Figure 2 As shown in FIG. 1 , one end thereof is connected to the metal plate 23, and the other end thereof is connected to the reference potential of the signal processing circuit 4. It should be noted that the ground pattern 7 may be as follows: Figure 1 As shown in the figure, the connector portion 21B is arranged on the first substrate 21, and is connected to the signal processing circuit 4 together with the signal lines of the excitation coils 11, 12 and the receiving coil 15. Alternatively, the ground pattern 7 may be connected to the signal processing circuit 4 in a different path from the signal lines of the excitation coils 11, 12 and the receiving coil 15.

[0049] [2. Function and effect]

[0050] (1) In the above-mentioned stator 2 and resolver 1, a ground pattern 7 is provided. Thus, the current generated in the first core 22A through the parasitic capacitance between the excitation coils 11, 12 (first coil) and the first core 22A can flow to the signal processing circuit 4 side. Therefore, the current (corresponding to the voltage change of the input signal) generated by the first core 22A is not easily generated on the second core 22B side arranged opposite to the receiving coil 15 (second coil). Therefore, it is possible to suppress a part of the input signal from being transmitted to the receiving coil 15 through the parasitic capacitance between the second core 22B side and the receiving coil 15. That is, the current that causes the noise can be grounded, and the noise itself contained in the output signal can be reduced. Therefore, the S / N ratio can be improved, and the detection accuracy of the resolver 1 can be improved.

[0051] In particular, in the sheet-type rotary transformer 1 having the coils 11 to 15 formed on the sheet-shaped substrates 21 and 31, it is difficult to sufficiently ensure the number of turns of each coil 11 to 15. Therefore, the magnetic flux of the excitation coils 11 and 12 and the transmission coil 14 is likely to be weakened, and the strength of the received signal is likely to be weakened. In such a rotary transformer 1, if the influence of the noise generated by the parasitic capacitance is removed by providing the ground pattern 7 on the stator 2, the S / N ratio can be improved even if the strength of the received signal is weak, so the detection accuracy of the rotary transformer 1 can be improved.

[0052] (2) When the input signal is a high-frequency AC signal of 100 kHz or higher, a current corresponding to the 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 further enjoyed, and the detection accuracy of the resolver 1 can be appropriately improved.

[0053] (3) In the above-mentioned stator 2, the ground pattern 7 is connected to the metal plate 23 and the signal processing circuit 4. In this way, the core 22 can be grounded to the signal processing circuit 4 indirectly by grounding the core 22 via the metal plate 23 electrically connected 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, a parasitic capacitance is formed between the core 22 and the metal plate 23, and part of the input signal may be transmitted to the receiving coil 15 as noise via the metal plate 23. In such a resolver 1, by connecting the ground pattern 7 to the metal plate 23 and the signal processing circuit 4, the effect of the ground pattern 7 can be further enjoyed, and the detection accuracy of the resolver 1 can be appropriately improved. In addition, instead of grounding both the first core 22A and the second core 22B individually, the cores 22 can be grounded collectively via the metal plate 23, so that the structure of the stator 2 can be simplified.

[0054] (4) In addition, when the excitation coils 11 and 12 are multi-pole coils as in the above-mentioned stator 2, the size of one magnetic pole formed in the first region R1 becomes small. Therefore, the magnetic flux of each magnetic pole of the excitation coils 11 and 12 is likely to be weakened, and the strength of the received signal is likely to be weakened. In such a resolver 1, if a ground pattern 7 is provided on the stator 2 to remove the influence of noise passing through the parasitic capacitance, the S / N ratio can be improved even if the strength of the received signal is weak, thereby improving the detection accuracy of the resolver 1.

[0055] [3. Others]

[0056] The above-mentioned structures of the stator 2 and the rotary transformer 1 are examples and are not limited to the above-mentioned structures. The stator 2 may be a stator 2 other than the rotary transformer 1 with two inputs and one output, as long as it has at least a first coil to which an input signal is input from the signal processing circuit 4, a second coil to which an output signal is output to the signal processing circuit 4, and a sheet-shaped substrate forming both the first coil and the second coil. That is, the rotary transformer 1 may not be a detector with two inputs and one output.

[0057] The rotary transformer may be, for example, a detector with one input and two outputs. In this case, the stator may have an excitation coil as a first coil and two receiving coils as a second coil. Alternatively, in the case where an excitation coil is provided on the rotor side, the stator may also have a transmitting coil as a first coil and two detection coils as a second coil. The rotary transformer may also be a rotary transformer in which an excitation coil and a detection coil are provided on the stator and a rotor has a conductor that generates a reverse magnetic field in a direction that cancels out the magnetic field of the excitation coil with a size corresponding to the rotation angle. That is, the coil may not be provided on the rotor of the rotary transformer.

[0058] The ground pattern 7 may also directly ground the core 22 to the signal processing circuit 4. That is, the ground pattern 7 may also connect one end of a wire constituting the ground pattern 7 to the core 22, and connect the other end to a wire serving as a reference potential of the signal processing circuit 4. In this case, it is preferred that the ground pattern 7 grounds both the first core 22A and the second core 22B to the signal processing circuit 4. In the case where 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 serving as a base of the stator 2 may be provided in place of the metal plate 23.

[0059] The "external device" described in the technical solution is an external device that at least inputs an input signal to the first coil and outputs an output signal from the second coil. The "external device" described in the technical solution may not be the signal processing circuit 4, for example, it may be a control device disposed outside the resolver 1.

[0060] Description of Reference Numerals

[0061] 1. Resolver

[0062] 2 Stator (resolver stator)

[0063] 3 Rotor (resolver rotor)

[0064] 4 Signal processing circuit (external device)

[0065] 7 Ground Pattern

[0066] 11 Sinusoidal excitation coil (excitation coil, first coil)

[0067] 12 Cosine excitation coil (excitation coil, first coil)

[0068] 15 Receiving coil (second coil)

[0069] 21. First substrate (substrate)

[0070] 22 cores

[0071] 23 Metal plate.

Claims

1. A resolver stator, which is a resolver stator provided in a resolver for detecting a rotation angle of a resolver rotor, characterized in that: have: A sheet-like substrate; a first coil provided on the substrate and receiving an input signal generated by an external device; a second coil, which is disposed on the substrate and outputs an output signal to the external device; a magnetic core which is arranged to overlap with the substrate in the axial direction and is arranged to face the first coil and the second coil in the axial direction; as well as A ground pattern grounds the core to the external device.

2. The rotary transformer stator according to claim 1, characterized in that: The input signal is an AC signal with a high frequency of more than 100 kHz.

3. The rotary transformer stator according to claim 2, characterized in that: The resolver stator further includes a metal plate arranged to overlap with the core in the axial direction. The ground pattern is connected to the metal plate and the external device.

4. The rotary transformer stator according to claim 3, characterized in that: The first coil or the second coil is a multi-pole coil.

5. A rotary transformer, characterized in that: The rotary transformer has: The rotary transformer stator according to any one of claims 1 to 4; and The resolver rotor is arranged to face the resolver stator in the axial direction.

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