Resolver stator and resolver

Abstract

A resolver stator (2) provided in a resolver (1) for detecting the rotation angle of a resolver rotor (3) has a sheet-like substrate (26). Input coils (11, 12) to which an input signal (S1) is input, a coil (15) to which an output signal (S3) is output, and cancel coils (21, 22) are disposed on a substrate (26). A phase signal (S2) that cancels the input signal (S1) is input to the cancellation coils (21, 22).

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, in Patent Document 1, it is disclosed that in a rotary transformer mounted on a motor, there is a substrate formed by a non-magnetic conductor, a plurality of coil patterns (coils) formed on the substrate, and a magnetic core arranged between the substrate and the plurality of coils. According to Patent Document 1, by shielding a plurality of coils with a substrate 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 coil from being offset under the action of the substrate composed of a non-magnetic conductor, thereby improving the S / N ratio. It should be noted that in the rotary transformer of Patent Document 1, as a plurality of coils, the detection coil or the excitation coil is formed on the same substrate as the transformer coil.

[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, multiple coils formed on the same substrate form parasitic capacitances between each other. 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 from the detection coil or the excitation coil to the transformer coil or vice versa 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 the 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 provided by a rotary transformer for detecting the rotation angle of a rotary transformer rotor, and has a sheet-shaped substrate. The substrate is provided with: an input coil to which an input signal is input; an output coil to which an output signal is output; and a cancelling coil to which a signal of a phase that cancels the input signal is input.

[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.

[0017] Figure 3 yes Figure 2 The main part ( Figure 2 An enlarged schematic diagram of the X portion). DETAILED DESCRIPTION

[0018] 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.

[0019] The resolver of the embodiment is a detector (sensor) that detects the rotation angle of a resolver rotor (hereinafter, also simply referred to as a "rotor") that rotates about a rotation axis C relative to a resolver stator (hereinafter, also simply referred to as a "stator"). The resolver stator of the embodiment is a stator included in such a resolver.

[0020] The stator of the embodiment has a sheet-shaped substrate. An input coil to which an input signal is input and an output coil to which an output signal is output are arranged on the substrate. The substrate is also provided with an elimination coil to which a signal of a phase that cancels the input signal is input. The stator of the embodiment is characterized in that the influence of a part of the input signal (noise) that interferes with the output signal due to unintentional electrical coupling between the input coil and the output coil arranged on the same substrate is reduced (the reduction of the S / N ratio is suppressed), and the above-mentioned noise is canceled by the signal input to the elimination coil. As a result, the S / N ratio is improved, thereby achieving an improvement in the detection accuracy of the rotary transformer.

[0021] 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 circumferentially around the rotation axis C is defined as the circumferential direction.

[0022] [1. Structure]

[0023] 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 rotary transformer 1. The rotary transformer 1 is applied to a servo motor (not shown), for example. 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.

[0024] The stator 2 and the rotor 3 are respectively as follows Figure 1 As shown in FIG. 1 , the substrates 26 and 36 are provided. Figure 2 As shown, a plurality of coils 11 to 15, 21 to 25 (sheet coils) are formed (printed). That is, the resolver 1 is a sheet-type resolver having a plurality of sheet coils 11 to 15, 21 to 25. By using sheet coils in this way, it is possible to achieve a reduction in the thickness of each coil 11 to 15, 21 to 25, and thus a reduction in the thickness of the resolver 1.

[0025] In the present embodiment, the rotary transformer 1 is a composite rotary transformer (multi-stage rotary transformer) that detects the rotation angle using multiple shaft angles, and includes: a first coil group 10, which includes first excitation coils 11 and 12 with shaft angles of aX (a is a natural number); and a second coil group 20, which includes second excitation coils 21 and 22 with shaft angles of bX (b is a natural number and 1≤b≤a-1). For example, the shaft angles of the first excitation coils 11 and 12 may be set to nX (n is a natural number greater than 2), and the shaft angles of the second excitation coils 21 and 22 may be set to 1X. The larger the value of n of the rotary transformer 1, the higher the angular resolution. It should be noted that in the present invention, the shaft angle of the second coil group 20 may not be 1X. However, the shaft angle of the second coil group 20 is preferably a shaft angle of a natural number smaller than n.

[0026] In addition, the rotary transformer 1 is a two-input one-output rotary transformer. The first coil group 10 includes five coils, namely, two first excitation coils 11, 12, a first detection coil 13, a first transmitting coil 14, and a first receiving coil 15 (transformer coil). As the two first excitation coils 11, 12, a first sine excitation coil 11 and a first cosine excitation coil 12 are provided. In addition, the second coil group 20 includes five coils, namely, two second excitation coils 21, 22, a second detection coil 23, a second transmitting coil 24, and a second receiving coil 25. As the two second excitation coils 21, 22, a second sine excitation coil 21 and a second cosine excitation coil 22 are provided.

[0027] The first excitation coils 11, 12, the first receiving coil 15, the second excitation coils 21, 22, and the second receiving coil 25 are provided on the first substrate 26 of the stator 2, and are electrically connected to the signal processing circuit 4 (external device). Hereinafter, these coils 11, 12, 15, 21, 22, 25 are also collectively referred to as "stator-side coils". The first input signal S1 (input signal) generated by the signal processing circuit 4 is input to the first excitation coils 11, 12, and the second input signal S2 generated by the signal processing circuit 4 is input to the second excitation coils 21, 22. The first receiving coil 15 outputs a first output signal S3 (output signal) to the signal processing circuit 4, and the second receiving coil 25 outputs a second output signal S4 to the signal processing circuit 4.

[0028] The resolver 1 of this embodiment reduces the influence of a portion (noise) of the first input signal S1 that interferes with the first output signal S3 due to the unintentional electrical coupling of the first excitation coils 11 and 12 and the first receiving coil 15 provided on the same first substrate 26. In the resolver 1, the above-mentioned noise is cancelled (offset) by the second input signal S2 input to the second excitation coils 21 and 22. That is, the first excitation coils 11 and 12 are the above-mentioned "input coils", the first receiving coil 15 is the above-mentioned "output coil", and the second excitation coils 21 and 22 are the above-mentioned "cancellation coils".

[0029] The stator 2 is a component fixed to a housing (not shown) of a device (such as a servo motor or a device for mounting the servo motor) to which the rotary transformer 1 is applied, and has a sheet-like first substrate 26. Figure 1 as well as Figure 2 As shown, the core 27 is arranged to overlap with the first substrate 26 in the axial direction, and the metal plate 28 is arranged to overlap with the core 27 in the axial direction.

[0030] The first substrate 26 is a thin sheet formed of a non-conductive resin (for example, polyimide). Figure 1 As shown, the base plate 26A has an annular base plate portion 26A extending around the rotation axis C, and a rectangular connector portion 26B protruding radially outward from a portion of the outer peripheral edge of the base plate portion 26A.

[0031] The base plate portion 26A is formed with Figure 2 The stator side coil shown. The substrate portion 26A is as shown Figure 2 As shown in the figure, the stator side coil has a greater thickness in the axial direction than the stator side coil. The stator side coil is formed in the substrate portion 26A so as not to be exposed in the axial direction (that is, to be built into the substrate portion 26A). Therefore, in other words, both sides of the stator side coil in the axial direction are covered by a polyimide sheet forming a part of the substrate portion 26A. It should be noted that, for example, copper foil is used for each of the stator side coils.

[0032] The connector portion 26B is a portion where the signal line of the stator side coil is routed, and Figure 1 As shown, the radially outer end portion thereof is connected to the connector portion 4A of the signal processing circuit 4. Thus, each stator-side coil is electrically connected to the signal processing circuit 4. It should be noted that the signal line of the stator-side coil is made of, for example, copper foil.

[0033] The shape, radial direction, and circumferential direction of the stator-side coil in the substrate portion 26A are not particularly limited. Figure 2As shown, the first excitation coils 11 and 12 , the first receiving coil 15 , the second excitation coils 21 and 22 , and the second receiving coil 25 are arranged in this order from the radially outer side to the inner side with gaps therebetween.

[0034] In the base plate portion 26A, for example, Figure 1 As shown in the figure, four regions R1, R2, R3, and R4 are provided in a circular ring shape centered on the rotation axis C and spaced apart from each other in the radial direction. The stator-side coils are arranged in the four regions R1, R2, R3, and R4, respectively. Hereinafter, the regions located most radially outward among the four regions R1, R2, R3, and R4 are referred to as the first region R1, the second region R2, the third region R3, and the fourth region R4 in order from the region located most radially outward toward the inside.

[0035] The first excitation coils 11 and 12 are formed in the first region R1 which is located at the radially outermost position, and n magnetic pole pairs are formed in the first region R1. It should be noted that in the first region R1, the two first excitation coils 11 and 12 can be as follows: Figure 2 Alternatively, the two first excitation coils 11 and 12 may be arranged at the same position in the axial direction and offset from each other in the circumferential direction.

[0036] The first receiving coil 15 is formed in the second region R2 arranged adjacent to the first region R1 on the radially inner side of the first region R1. That is, the first receiving coil 15 is arranged adjacent to the first exciting coils 11 and 12 when viewed from the axial direction. The first receiving coil 15 is a transformer coil that receives a signal from the first transmitting coil 14, and is formed by laying out a winding in a spiral shape around the rotation axis C in the second region R2.

[0037] The second excitation coils 21, 22 are formed in the third region R3 which is arranged adjacent to the second region R2 on the radial inner side of the second region R2, and form a magnetic pole pair in the third region R3. That is, the second excitation coils 21, 22 are arranged adjacent to the first receiving coil 15 when viewed from the axial direction. In other words, the first receiving coil 15 is arranged between the first excitation coils 11, 12 and the second excitation coils 21, 22, and the second receiving coil 25 is not arranged between the first excitation coils 11, 12 and the second excitation coils 21, 22 and the first receiving coil 15. It should be noted that the two second excitation coils 21, 22, like the two first excitation coils 11, 12, can be arranged in the third region R3 as shown in FIG. Figure 2 Although they are arranged so as to overlap in the axial direction as shown, this does not necessarily have to be the case.

[0038] The second receiving coil 25 is formed in the fourth region R4 located most radially inward. The second receiving coil 25 is a transformer coil that receives a signal from the second transmitting coil 24 and is formed by spirally arranging windings around the rotation axis C in the fourth region R4.

[0039] The core 27 is a magnetic member that is stacked on the first substrate 26 on the second direction D2 side (the side away from the rotor 3) and is arranged to face the stator-side coils in the axial direction. Examples of magnetic materials for the core 27 include electromagnetic steel plates, magnetic sheets containing amorphous or ferrite powders, and the like. The core 27 may be, for example, Figure 1 As shown, it is composed of a plurality of members in the shape of rings having substantially the same diameter as the four regions R1 , R2 , R3 , and R4 .

[0040] The metal plate 28 is a metal member stacked on the core 27 on the second direction D2 side, and has a shape substantially the same as the substrate portion 26A of the first substrate 26 when viewed from the axial direction, and is in a plate shape (sheet shape) that covers the substrate portion 26A from the second direction D2 side. The metal plate 28 may be directly fixed to the core 27 by metal screws (not shown) or the like, or may be arranged on the core 27 by means of an adhesive sheet (insulating material) (not shown).

[0041] The metal plate 28 is made of, for example, a sheet of non-magnetic aluminum. However, the metal plate 28 may not be a non-magnetic material, and may be, for example, a magnetic material such as an iron plate. By providing the metal plate 28, 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 first substrate 26 and the core 27 which are in the form of a thin sheet. 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 28 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 28 as a shield against external noise (electromagnetic waves). For example, it may also be copper.

[0042] The rotor 3 is a member supported by the stator 2 so as to be rotatable integrally with the rotation axis C (around the rotation center). Figure 1 as well as Figure 2 As shown, a second substrate 36 , a core 37 , and a metal plate 38 are provided.

[0043] The second substrate 36 is a sheet made of a non-conductive resin (for example, polyimide) similarly to the first substrate 26. Figure 2The first detection coil 13, the first transmission coil 14, the second detection coil 23, and the second transmission coil 24 are shown. In the second substrate 36, the coils 13, 14, 23, 24 can be covered on both sides of the axial direction by a polyimide sheet forming a part of the second substrate 36, similarly to the stator-side coils formed on the first substrate 26. It should be noted that these coils 13, 14, 23, 24 are made of, for example, copper foil. The second substrate 36 is, for example, Figure 1 As shown, it has an annular shape having the same diameter as the base plate portion 26A of the first base plate 26 when viewed from the axial direction.

[0044] In the second substrate 36, the first detection coil 13, the first transmission coil 14, the second detection coil 23, and the second transmission coil 24 are arranged axially opposite to the first excitation coils 11, 12, the first reception coil 15, the second excitation coils 21, 22, and the second reception coil 25. For example, the first detection coil 13 is provided in the fifth annular region R5 (see Figure 1 ), the first transmitting coil 14 is disposed in a sixth annular region R6 (see Figure 1 The second detection coil 23 is disposed in a seventh annular region R7 (see Figure 1 ), the second transmitting coil 24 is provided in an annular eighth region R8 (refer to Figure 1 ).

[0045] The first detection coil 13 and the first transmission coil 14 are as follows Figure 2 As shown, the second detection coil 23 and the second transmitting coil 24 are electrically connected to each other (connected in series). In addition, the second detection coil 23 and the second excitation coil 11 and 12 have an axial angle of nX, and form n magnetic pole pairs in the fifth region R5. The second detection coil 23 and the second excitation coil 21 and 22 have an axial angle of 1X, and form a magnetic pole pair in the seventh region R7. In addition, the first transmitting coil 14 and the second transmitting coil 24 are each a transformer coil that sends a signal to the first receiving coil 15 and the second receiving coil 25, respectively, and are formed by spirally arranging windings around the rotation axis C in the sixth region R6 and the eighth region R8, respectively.

[0046] The core 37 is a magnetic member that is stacked on the second substrate 36 on the first direction D1 side (the side away from the stator 2) and is arranged axially opposite to the first detection coil 13, the first transmission coil 14, the second detection coil 23, and the second transmission coil 24. The core 37 can be made of the same magnetic material as the core 27 of the stator 2. For example, the core 37 can be made of Figure 1As shown, it is composed of a plurality of members in the shape of a ring having substantially the same diameter as the four regions R5, R6, R7, and R8.

[0047] The metal plate 38 is a member arranged to overlap with the core 37 on the first direction D1 side, and has a shape substantially the same as the second substrate 36 when viewed from the axial direction, and is in a plate shape (sheet shape) that covers the second substrate 36 from the first direction D1 side. The metal plate 38 can be made of a non-magnetic aluminum sheet, for example, similarly to the metal plate 28 of the stator 2. In addition, the metal plate 38 can be arranged on the core 37 via an adhesive sheet (insulating material) not shown, similarly to the metal plate 28 of the stator 2.

[0048] The signal processing circuit 4 is a circuit that generates the first input signal S1 and the second input signal S2 and outputs the rotation angle (angle information 7) of the rotor 3 relative to the stator 2 based on the received first output signal S3 and the second output signal S4. The signal processing circuit 4 is, for example, provided outside the resolver 1 and can be as follows: Figure 1 As shown, a base plate having an annular shape extending around the rotation axis C is formed at a position different from the stator 2 and the rotor 3 in the axial direction.

[0049] like Figure 2 As shown, the signal processing circuit 4 includes a signal generating circuit 5 and a signal processing circuit 6. The signal generating circuit 5 generates a first input signal S1 and a second input signal S2, and inputs the first excitation coils 11 and 12 and the second excitation coils 21 and 22. The signal processing circuit 6 outputs angle information 7 corresponding to the rotation angle based on the first output signal S3 and the second output signal S4 output from the first receiving coil 15 and the second receiving coil 25.

[0050] In the present embodiment, the resolver 1 is a modulated wave resolver that receives an amplitude modulated high frequency (e.g., 100 kHz or more) AC signal (signal waveform includes a carrier wave and a modulated wave) and detects the rotation angle based on a phase modulated signal generated in the first detection coil 13 and the second detection coil 23 using the amplitude modulated high frequency AC signal. The signal generation circuit 5 inputs the amplitude modulated AC signal (excitation signal) as the first input signal S1 to the first excitation coils 11 and 12. The signal generation circuit 5 inputs AC signals whose phases of the modulated waves differ by 90 degrees to the first sine excitation coil 11 and the first cosine excitation coil 12, respectively.

[0051] In addition, the signal generating circuit 5 inputs the following signal as the second input signal S2, which is an amplitude modulated AC signal (excitation signal) and is a signal of a phase that cancels the first input signal S1, to the second excitation coils 21 and 22 as cancellation coils. The signal generating circuit 5 inputs AC signals whose phases of modulated waves differ by 90 degrees from each other to the second sine excitation coil 21 and the second cosine excitation coil 22, respectively.

[0052] The signal generating circuit 5 inputs the following signal to the second excitation coils 21 and 22 as the above-mentioned “signal of the phase that cancels the first input signal S1”, which is a signal in which the phase of the carrier wave relative to the phase of the carrier wave of the first input signal S1 has an electrical angle difference within a range of 90 degrees or more and 270 degrees or less. The signal generating circuit 5 of this embodiment inputs a signal of an opposite phase to the phase of the carrier wave of the first input signal S1 (a signal with a phase difference of 180 degrees) to the second excitation coils 21 and 22.

[0053] Specifically, the signal generation circuit 5 inputs sin(ω) to the first sinusoidal excitation coil 11 of the first excitation coils 11 and 12 whose shaft angle is nX. c t)·cos(ω m t) is used as the first input signal S1. In addition, the first cosine excitation coil 12 is input with respect to the first sinusoidal excitation signal S11. m t)〕The phase difference is 90 degrees sin(ω c t)·sin(ω m t) is used as the first input signal S1.

[0054] The signal generating circuit 5 inputs the following signal as the second input signal S2 to the second sinusoidal excitation coil 21 of the second excitation coils 21 and 22 with an axis angle multiplier of 1X. The signal is a carrier wave [sin (ω)] with respect to the first sinusoidal excitation signal S11. c t)〕becomes the opposite phase of -sin(ω c t)·cos(ω m t) of the cosine waveform of the second sine excitation signal S21. In addition, the second cosine excitation coil 22 is input with the following signal as the second input signal S2, which is the carrier wave [sin (ω)] relative to the first cosine excitation signal S12. c t)] becomes the opposite phase and relative to the modulation wave of the second sinusoidal excitation signal S21 [cos(ω m t)〕with a phase difference of 90 degrees -sin(ω c t)·sin(ω mt) a second cosine excitation signal S22 having a sinusoidal waveform.

[0055] In the first coil group 10, when the first input signal S1 is input to the first exciting coils 11 and 12, the first exciting coils 11 and 12 are excited to generate magnetic flux (see Figure 2 The magnetic flux interlinks with the first 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 first detection coil 13, and the first transmission coil 14 is excited to generate a magnetic flux (see Figure 2 The magnetic flux interlinks with the first receiving coil 15 on the stator 2 side 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 the first output signal S3, and is converted by the signal processing circuit 6 into angle information 7 corresponding to the rotation angle and output.

[0056] The same is true for the second coil group 20. When the second input signal S2 is input to the second excitation coils 21 and 22, the second excitation coils 21 and 22 are excited to generate magnetic flux (see Figure 2 The magnetic flux interlinks with the second detection coil 23 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 second detection coil 23, and the second transmission coil 24 is excited to generate a magnetic flux (see Figure 2 The magnetic flux interlinks with the second receiving coil 25 on the stator 2 side 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 the second output signal S4, and is converted by the signal processing circuit 6 into angle information 7 corresponding to the rotation angle and output.

[0057] Here, in the stator 2 of the rotary transformer 1 as described above, the gap (radial gap) between the first excitation coils 11 and 12 and the first receiving coil 15 formed on the same first substrate 26 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.

[0058] In the stator 2, a part of the first input signal S1 input to the first excitation coils 11 and 12 may leak through the parasitic capacitance and be transmitted to the first receiving coil 15 as noise. Figure 3As shown by the middle dotted line, in the stator 2, the gap between the first sinusoidal excitation coil 11 and the first receiving coil 15 becomes a parasitic capacitor. Due to the effect of this parasitic capacitor, the first sinusoidal excitation coil 11 and the first receiving coil 15 are unintentionally electrically coupled, so that a part of the first sinusoidal excitation signal S11 is transmitted to the first receiving coil 15 as sinusoidal noise S11′. Similarly, the gap between the first cosine excitation coil 12 and the first receiving coil 15 becomes a parasitic capacitor, and due to the effect of this parasitic capacitor, a part of the first cosine excitation signal S12 is transmitted to the first receiving coil 15 as cosine noise S12′.

[0059] As a result, in the first receiving coil 15, a part of the first input signal S1 transmitted through the parasitic capacitance interferes with the signal S15 (hereinafter referred to as "received signal S15") received from the first transmitting coil 14 as noise (sine noise S11' and cosine noise S12'), and the waveform including the noise is output as the first output signal S3 to the signal processing circuit 6. As a result, the S / N ratio is reduced, which may cause a reduction in the detection accuracy of the resolver 1.

[0060] Therefore, in the stator 2 of the present embodiment, as a structure for reducing the influence of such noise on the first output signal S3, the second excitation coils 21 and 22 are provided as cancellation coils, and a signal of a phase that cancels the first input signal S1 is input to the second excitation coils 21 and 22. In the stator 2, the gap between the second excitation coils 21 and 22 and the first receiving coil 15 becomes a parasitic capacitance, and a part of the second input signal S2 is transmitted to the first receiving coil 15 through the parasitic capacitance. As a result, a part of the first input signal S1 transmitted to the first receiving coil 15 is canceled by a part of the second input signal S2, thereby achieving an improvement in the S / N ratio.

[0061] In detail, in the stator 2, if Figure 3 As shown by the dotted line, the gap between the second sine excitation coil 21 and the first receiving coil 15 becomes a parasitic capacitor. Under the action of the parasitic capacitor, the second sine excitation coil 21 is coupled to the first receiving coil 15, so that a part of the second sine excitation signal S21 is transmitted to the first receiving coil 15 as a sine cancellation signal S21′. Similarly, the gap between the second cosine excitation coil 22 and the first receiving coil 15 becomes a parasitic capacitor, and under the action of the parasitic capacitor, a part of the second cosine excitation signal S22 is transmitted to the first receiving coil 15 as a cosine cancellation signal S22′.

[0062] As a result, in the first receiving coil 15, the sinusoidal noise S11′ and the sinusoidal cancellation signal S21′ cancel each other ( Figure 3 The cosine noise S12′ and the cosine cancellation signal S22′ cancel each other ( Figure 3 In this way, the noises S11 ′, S12 ′ transmitted to the first receiving coil 15 are offset by the cancellation signals S21 ′, S22 ′, so that in the first receiving coil 15 , the receiving signal S15 is output as the first output signal S3 to the signal processing circuit 4 .

[0063] [2. Function and effect]

[0064] (1) In the above-mentioned stator 2 and resolver 1, first excitation coils 11 and 12 (input coils) to which first input signal S1 is input and first receiving coil 15 (output coil) to output first output signal S3 are arranged on first substrate 26. Second excitation coils 21 and 22 as cancelling coils are also arranged on first substrate 26. Second input signal S2 of a phase that cancels first input signal S1 is input to second excitation coils 21 and 22.

[0065] The first receiving coil 15 forms a parasitic capacitance with the first exciting coils 11 and 12 disposed on the same first substrate 26, so that a part of the first input signal S1 is transmitted to the first receiving coil 15 as noise (noise S11', S12') and interferes with the first output signal S3. However, the first receiving coil 15 can cancel the above-mentioned noise by using a part of the second input signal S2 (cancellation signals S21', S22') transmitted through the parasitic capacitance generated between the first receiving coil 15 and the second exciting coils 21 and 22 disposed on the same first substrate 26.

[0066] In this way, in the above-mentioned stator 2 and resolver 1, by utilizing the parasitic capacitance parasitically generated between the second excitation coils 21 and 22 other than the first excitation coils 11 and 12 and the first receiving coil 15, the signals that become noise components can be cancelled out in the first receiving coil 15 and removed. Therefore, the S / N ratio can be improved, and the detection accuracy of the resolver 1 can be improved.

[0067] In particular, in the sheet-type rotary transformer 1 having coils 11 to 15, 21 to 25 formed on sheet-shaped substrates 26, 36, it is difficult to sufficiently ensure the number of turns of each coil 11 to 15, 21 to 25. Therefore, the magnetic flux of the first excitation coils 11, 12 and the first transmitting coil 14 is likely to be weakened, and the intensity of the received signal S15 is likely to be weakened. In such a rotary transformer 1, if the second excitation coils 21, 22 are provided to which the second input signal S2 of a phase that cancels the first input signal S1 is input, and the signals that become noise components are canceled in the first receiving coil 15, the S / N ratio can be improved even if the intensity of the received signal S15 is weak, so the detection accuracy of the rotary transformer 1 can be improved.

[0068] (2) In the above-mentioned stator 2 and resolver 1, as the second input signal S2 that cancels the phase of the first input signal S1, a signal whose phase difference with respect to the phase of the carrier of the first input signal S1 is within a range of 90 degrees or more and 270 degrees or less is input. By such a phase difference between the carriers of the first input signal S1 and the second input signal S2, the noises S11′ and S12′ can be appropriately cancelled out by the cancellation signals S21′ and S22′, thereby improving the detection accuracy of the resolver 1.

[0069] (3) In the above-mentioned stator 2 and resolver 1, the first receiving coil 15 is arranged between the first excitation coils 11 and 12 and the second excitation coils 21 and 22. With such an arrangement structure, the signal strengths of the noise S11′ and S12′ and the cancellation signals S21′ and S22′ transmitted to the first receiving coil 15 can be made equal. Therefore, the signals that become noise components can be more appropriately offset in the first receiving coil 15, so that the detection accuracy of the resolver 1 can be improved.

[0070] (4) The above-mentioned resolver 1 is a composite resolver including a first coil group 10 and a second coil group 20. The first coil group 10 includes first excitation coils 11 and 12 as input coils and a first receiving coil 15 as an output coil. The second coil group 20 includes second excitation coils 21 and 22 having an axial angle different from that of the first excitation coils 11 and 12. Thus, by utilizing the second excitation coils 21 and 22 of the second coil group 20 as cancellation coils, it is possible to cancel the signals (noise S11′ and S12′) leaking from the first excitation coils 11 and 12 without necessarily providing a coil dedicated to noise cancellation.

[0071] (5) In particular, as in the above-mentioned stator 2, when the axial angle multiplier of the first excitation coils 11 and 12 is larger than the axial angle multiplier of the second excitation coils 21 and 22, the size of one magnetic pole of the first excitation coils 11 and 12 formed in the first region R1 becomes smaller than the size of one magnetic pole of the second excitation coils 21 and 22 formed in the second region R2. Therefore, the magnetic flux of each magnetic pole of the first excitation coils 11 and 12 is likely to be weakened, and the intensity of the received signal S15 is likely to be weakened. In such a rotary transformer 1, if the second excitation coils 21 and 22 of the second coil group 20 are utilized and the signals that become noise components are offset in the first receiving coil 15, the S / N ratio can be improved even if the intensity of the received signal S15 is weak. Therefore, the detection accuracy of the rotary transformer 1 can be improved. In other words, by utilizing the excitation coil with a smaller axial angle multiplication factor (the second excitation coils 21 , 22 ) as a cancellation coil, the S / N ratio of the received signal of the coil group including the excitation coil with a larger axial angle multiplication factor (the first excitation coils 11 , 12 ) can be appropriately improved without adding any components.

[0072] [3. Others]

[0073] The above-mentioned structure of the stator 2 and the rotary transformer 1 is an example and is not limited to the above-mentioned structure. The stator 2 only needs to have at least an input coil to which an input signal is input, an output coil to output an output signal, an elimination coil to which a signal of a phase that cancels the input signal is input, and a substrate on which these coils are arranged. For example, the axial angle multiplier of the first excitation coils 11, 12 and the second excitation coils 21, 22 is not limited to the above-mentioned axial angle multiplier. For example, the axial angle multiplier of the first excitation coils 11, 12 can be 1X, and the axial angle multiplier of the second excitation coils 21, 22 can be nX.

[0074] The stator 2 may not be the stator 2 of the composite rotary transformer 1 that detects the rotation angle using multiple shaft angle multiplications, but may be the stator of a rotary transformer that detects the rotation angle using one shaft angle multiplication. In this case, the coils 21 to 25 of the second coil group 20 may be omitted, and a coil dedicated to the cancellation coil to which a signal of a phase that cancels the first input signal S1 (input signal) is input may be provided on the stator instead of the second excitation coils 21 and 22.

[0075] The stator 2 may not be the stator 2 of the rotary transformer 1 with two inputs and one output, but may be the stator of the rotary transformer with one input and two outputs. In this case, one input coil, two output coils, and one cancellation coil may be provided on the stator. That is, the rotary transformer 1 may not be a detector with two inputs and one output, but may be a detector with one input and two outputs.

[0076] The rotary transformer 1 may not be a rotary transformer in which the excitation coils 11, 12, 21, 22 are provided on the stator 2 and the detection coils 13, 23 are provided on the rotor 3. For example, the rotary transformer may be a rotary transformer in which the excitation coil is provided on the rotor and the detection coil is provided on the stator. Alternatively, the rotary transformer may be a rotary transformer in which the excitation coil and the detection coil are provided on the stator and the rotor has a conductor that generates a reverse magnetic field in a direction that cancels 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.

[0077] The stator may be provided with at least an input coil, an output coil, and a cancellation coil on the same substrate, and their configuration is not limited to the above configuration. For example, in the above-mentioned stator 2, the first receiving coil 15 is arranged between the first excitation coils 11, 12 and the second excitation coils 21, 22, but it may also be that both the first excitation coils 11, 12 and the second excitation coils 21, 22 are arranged radially inside or outside the first receiving coil 15. It may also be that not only the first receiving coil 15 but also the second receiving coil 25 is arranged between the first excitation coils 11, 12 and the second excitation coils 21, 22. That is, the above-mentioned configuration of the stator side coil is an example and is not limited to the above-mentioned configuration.

[0078] The signal input to the cancellation coil only needs to be a signal of a phase that cancels the input signal, and does not need to be a signal of an opposite phase to the phase of the carrier of the input signal. A portion of the input signal transmitted to the output coil via parasitic capacitance (the above-mentioned noise S11′, S12′) is sometimes phase-shifted relative to the input signal due to the relationship between parasitic capacitance and inductance. Similarly, a portion of the signal of the cancellation coil transmitted to the output coil (the above-mentioned cancellation signal S21′, S22′) is sometimes phase-shifted relative to the signal input to the cancellation coil. Therefore, the phase of the carrier of the signal input to the cancellation coil is preferably appropriately set within the range of a phase difference of more than 90 degrees and less than 270 degrees relative to the carrier of the input signal, taking such an offset into consideration.

[0079] Description of Reference Numerals

[0080] 1. Resolver

[0081] 2 Stator (resolver stator)

[0082] 3 Rotor (resolver rotor)

[0083] 4 Signal processing circuit (external device)

[0084] 10 First coil group

[0085] 11 First sinusoidal excitation coil (first excitation coil, input coil)

[0086] 12 First cosine excitation coil (first excitation coil, input coil)

[0087] 15. First receiving coil (transformer coil, output coil)

[0088] 20 Second coil group

[0089] 21 Second sinusoidal excitation coil (second excitation coil, elimination coil)

[0090] 22 Second cosine excitation coil (second excitation coil, elimination coil)

[0091] 26. First substrate (substrate)

[0092] S1 First input signal (input signal)

[0093] S2 Second input signal (a signal with a phase that cancels the input signal)

[0094] S3 First output signal (output signal)

[0095] S11 First sinusoidal excitation signal (input signal)

[0096] S12 First cosine excitation signal (input signal)

[0097] S21 Second sinusoidal excitation signal (a signal with a phase that cancels the input signal)

[0098] S22 Second cosine excitation signal (a signal with a phase that cancels out the input signal).

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: The rotary transformer stator has a sheet-shaped substrate. An input coil to which an input signal is input, an output coil to which an output signal is output, and a cancel coil are arranged on the substrate. A signal having a phase for canceling the input signal is input to the cancel coil.

2. The rotary transformer stator according to claim 1, characterized in that: The signal of the phase that cancels the input signal is a signal in which the phase of a carrier wave differs from the phase of a carrier wave of the input signal in a range of not less than 90 degrees and not more than 270 degrees.

3. The rotary transformer stator according to claim 1, characterized in that: The output coil is arranged between the input coil and the cancel coil when viewed from the axial direction.

4. The rotary transformer stator according to claim 1, characterized in that: The rotary transformer is a composite rotary transformer having a first coil group and a second coil group, wherein the first coil group includes a first excitation coil as the input coil and a transformer coil as the output coil, and the second coil group includes a second excitation coil having an axis angle different from that of the first excitation coil. The second exciting coil is arranged on the substrate as the cancel coil.

5. The rotary transformer stator according to claim 4, characterized in that: The axis angle multiple of the first excitation coil is aX, The axial angle multiple of the second excitation coil is bX, Among them, a and b are natural numbers, and 1≤b≤a-1.

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

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