Resolver

Abstract

To provide a compact, high-resolution resolver. [Solution] A resolver comprising a stator core 10a having a plurality of radially protruding teeth T1, T2 arranged in the circumferential direction, and a plurality of coils C1, C2 mounted on each of the plurality of teeth T1, T2. In the radial direction of the stator core 10a, the position of at least one of the coils C2 is different from the position of the other coils C1.

Description

Technical Field

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[0003] , , , , , , <00000​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​A stator core having multiple teeth that protrude radially and are arranged circumferentially, The set comprises a plurality of coils attached to each of the plurality of teeth, In the radial direction of the stator core, the position of at least one coil is different from the position of the other coils. [Effects of the Invention]

[0007] According to this disclosure, a compact, high-resolution resolver can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] This is a top view of a resolver according to an embodiment of the present disclosure. [Figure 2] This is a partially enlarged view of the stator before mounting the output coil according to the embodiment of this disclosure. [Figure 3] This is a schematic top view of an output coil according to an embodiment of the present disclosure. [Figure 4] This is a partially enlarged view of the output coil after its implementation according to the embodiment of this disclosure. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. For the sake of clarity, the description of components having the same reference numeral as those already described in the description of the embodiments will be omitted. Furthermore, the dimensions of the components shown in these drawings may differ from the actual dimensions of the components for the sake of clarity.

[0010] Figure 1 is a top view of the resolver 100 according to this embodiment. The resolver 100 is an outer rotor type and comprises a substantially ring-shaped stator 10 and a substantially ring-shaped rotor 20 rotatably mounted on the outer circumference of the stator 10. The resolver 100 detects the amount of rotation of the rotor 20 relative to the stator 10. The resolver 100 is a sensor that detects the amount of rotation of a rotating body, such as a motor. For the purposes of this explanation, the resolver 100 will be assumed to detect the amount of rotation of a motor relative to its housing.

[0011] The stator 10 has a roughly ring-shaped stator core 10a and roughly rectangular parallelepiped-shaped teeth T that protrude radially outward from the stator core 10a. The teeth T are arranged at equal intervals in the circumferential direction. In the example shown in Figure 1, resolver coils C are attached to each tooth T. The teeth T are configured such that the distance from the rotation center O to the tip of each tooth T is equal to that of the others.

[0012] The rotor 20 is a component that can rotate relative to the stator 10. In the example shown in Figure 1, the rotor 20 is located on the outer circumference of the stator 10. The rotor 20 is fixed to a component such as a motor shaft rotated by the motor to be detected, or a gear attached to the motor shaft. The rotor 20 is a substantially ring-shaped component, and its outer surface may form a circle when viewed from the front.

[0013] The inner surface of the rotor 20 is sequentially provided with irregularities 20a in the circumferential direction. These irregularities 20a cause the radial thickness of the rotor 20 (the dimension from the inner surface to the outer surface) to fluctuate periodically. In the example shown in Figure 1, the radial thickness of the rotor 20 changes periodically along the circumferential direction. In other words, the gap G from the inner surface of the rotor 20 to the tip of the teeth T of the stator 10 fluctuates in the circumferential direction. Therefore, when the rotor 20 rotates relative to the stator 10, the gap permeance between the rotor 20 and the stator 10 changes sinusoidally according to the rotation angle θ of the rotor 20.

[0014] As shown in Figure 3, the resolver coil C includes an excitation coil Cin and an output coil Cout. An AC power supply (not shown) is connected to the excitation coil Cin, and when AC current flows through the excitation coil Cin, a magnetic flux M is generated from the teeth T on which the resolver coil C is mounted. This magnetic flux M is linked to the output coil Cout.

[0015] This flux linkage generates an electromotive force (resolver signal) in the output coil Cout, corresponding to the rotation angle θ of the rotor 20. An RD converter (not shown) is connected to the output coil Cout, and the RD converter detects the rotation angle of the motor based on this resolver signal.

[0016] In the example shown in Figure 1, 16 sets of irregularities 20a are provided on the inner circumferential surface of the rotor 20. Therefore, the axis double angle is 16X, and when the rotor 20 rotates once, output signals equivalent to 16 cycles of the motor are acquired. Note that in this embodiment, the axis double angle is not limited to 16X.

[0017] Figure 2 is a partially enlarged view of the stator 10 before the implementation of the resolver coil C according to the present disclosure. As shown in Figure 2, the stator 10 is provided with first teeth T1 and second teeth T2, which have different shapes from each other. The first teeth T1 are provided with a stepped portion S, while the second teeth T2 are not provided with a stepped portion. The first teeth T1 and the second teeth T2 are arranged alternately in the circumferential direction. The radial heights of the first teeth T1 and the second teeth T2 are approximately the same. In the following description, when the first teeth T1 and the second teeth T2 are not specifically distinguished, they will simply be referred to as teeth T.

[0018] The stepped portion S is a part for positioning the resolver coil C in the radial direction. In the example shown in FIG. 2, the stepped portion S is a rectangular portion provided at the base end portion of the first tooth T1 and wider than the first tooth T1. The stepped portion S positions the resolver coil C in the radial direction by preventing the upper surface F (the radially outer surface) of the stepped portion S from moving radially inward relative to the upper surface F of the resolver coil C. Since the first teeth T1 and the second teeth T2 are alternately provided in the circumferential direction, as shown in FIG. 1, the distance d1 from the rotation center O of the resolver coil C1 is different from the distance d2 from the rotation center O of the resolver coil C2 adjacent in the circumferential direction. In the example shown in FIG. 2, an example in which the stepped portion S is formed of a rectangular portion has been described, but the shape of the stepped portion S is not limited to this.

[0019] FIG. 3 is a schematic top view of the resolver coil C according to an embodiment of the present disclosure. The resolver coil C includes an excitation coil Cin, an output coil Cout, and a pair of substantially rectangular parallelepiped-shaped first lid portions L-1 and second lid portions L-2.

[0020] The excitation coil Cin includes a coil bobbin B1 and a winding W1. The coil bobbin B1 includes a substantially rectangular parallelepiped-shaped core portion BO1 extending in the central axis direction Lo, and a pair of substantially rectangular parallelepiped-shaped first flanges FU1 and second flanges FL1. The pair of first flanges FU1 and second flanges FL1 are provided so as to sandwich the core portion BO1 in the central axis direction Lo. The winding W1 is wound around the core portion BO1 of the coil bobbin B1. Since the output coil Cout has the same configuration as the excitation coil Cin, the description thereof is omitted.

[0021] The excitation coil Cin and the output coil Cout are sandwiched in the central axis direction Lo by a pair of first lid portions L1 and second lid portions L2. The excitation coil Cin, the output coil Cout, the pair of first lid portions L1 and second lid portions L2 are provided with an internal space S through which teeth T are inserted. In FIG. 1, when resolver coils C are respectively mounted on all the teeth T, the first lid portion L1 is located on one of the radially outer side and the radially inner side, and the second lid portion L2 is located on the other of the radially outer side and the radially inner side.

[0022] Here, let the length in the lateral direction of the paper surface of FIG. 3 of the first lid portion L1, the second lid portion L2, the first flange FU1 and the second flange FL1 of the coil bobbin B1, and the first flange FU2 and the second flange FL2 of the coil bobbin B2 be D2 (hereinafter also referred to as the width D2 of the resolver coil). Also, let the length in the lateral direction of the paper surface of FIG. 3 of the winding W1 wound around the core BO1 of the coil bobbin B1 and the winding W2 wound around the core BO2 of the coil bobbin B2 be D3 (hereinafter also referred to as the width D3 of the winding). Also, let the length in the lateral direction of the paper surface of FIG. 3 of the internal space S be D4 (hereinafter also referred to as the width D4 of the internal space).

[0023] Also, let the circumferential length of the tip portion of the tooth T shown in FIG. 2 be D0 (hereinafter also referred to as the width D0 of the tooth). Also, let the circumferential length of the step portion S be D1 (hereinafter also referred to as the width D1 of the step portion).

[0024] In the excitation coil Cin, the winding W1 wound around the core BO1 is accommodated inside the outer surfaces of the first flange FU1 and the second flange FL1 of the coil bobbin B1. Therefore, the width D2 of the output coil is larger than the width D3 of the winding (D2 > D3). Also, the width D3 of the winding is larger than the width D4 of the internal space (D3 > D4). The same dimensional relationship holds for the output coil Cout.

[0025] Furthermore, the width D4 of the internal space is set to be greater than the width D0 of the teeth shown in Figure 2, and smaller than the width D1 of the stepped portion (D1 > D4 > D0). Since the width D4 of the internal space is greater than the width D0 of the teeth T, the resolver coil C can be attached to the teeth T. Also, since the width D4 of the internal space is smaller than the width D1 of the stepped portion, the resolver coil C is positioned radially in contact with the upper surface F of the stepped portion S on the first tooth T1.

[0026] Furthermore, if the radial height of the second tooth T2 shown in Figure 2 is denoted as HT and the radial height of the stepped portion S as HS, the difference in radial heights between the two, HT-HS, is set to be greater than the height HC of the resolver coil C shown in Figure 3 (HT-HS>HC). As a result, the resolver coil C can be attached to the first tooth T1 without protruding radially outward from the tip of the first tooth T1.

[0027] Figure 4 is a partially enlarged view of the stator 10 after the resolver coil C according to the embodiment of this disclosure has been mounted. As shown in Figure 4, resolver coils C1 and C2 are mounted on teeth T1 and T2, respectively. Furthermore, resolver coil C1 is positioned radially so as to be in contact with the tip surface F of the stepped portion S of the first tooth T1. The resolver coils C1 and C2 have the same structure and substantially the same winding specifications. Specifically, the dimensions, shape, number of turns, resistance value, and inductance of resolver coils C1 and C2 are substantially the same, and they share a common coil bobbin. This makes it possible to reduce the component cost of the resolver coil C.

[0028] In Figure 4, the outer surface including the tip surface of tooth T is denoted as G1, and the interface between the stator core 10a and tooth T is denoted as G2. Furthermore, the region on the interface surface G2 from the central axis L1 of the first tooth T1 to the central axis L2 of the second tooth T2 is called A1, and the arc length of this region A1 is denoted as R1. Also, the region on the circumference passing through the upper surface F of the stepped portion S from the central axis L1 of the first tooth T1 to the central axis L2 of the second tooth T2 is called A2, and the arc length of this region A2 is denoted as R2.

[0029] Here, if, contrary to this embodiment, the first teeth T1 do not have the step portion S, the resolver coil C1, similar to the resolver coil C2, would be mounted so as to contact the boundary surface G2 of the stator core 10a.

[0030] In this case, the right half of the resolver coil C1 and the left half of the resolver coil C2 would be located in the region A1. The total value of half the length D2 / 2 of the width D2 of the resolver coil C1 and half the length D2 / 2 of the width D2 of the resolver coil C2 is D2. Therefore, if the total value D2 is greater than or equal to the arc length R1 of the region A1, the resolver coils C1 and C2 would interfere with each other at the midpoint between the first teeth T1 and the second teeth T2 on the boundary surface G2. Thus, in order to prevent interference between the resolver coils C1 and C2, it is necessary to increase the diameter of the stator core 10a and make the arc length R1 of the region A1 larger than the total value D2, resulting in an increase in the size of the resolver.

[0031] Therefore, in this embodiment, as shown in FIG. 4, a step portion S having a width D1 narrower than the width D2 of the resolver coil C1 is provided on the first teeth T1. This makes the radial positions of the adjacent resolver coils C different. This will be described in detail later.

[0032] As shown in FIG. 4, the right half of the step portion S and the left half of the resolver coil C2 are included in the region A1. The total value of half the length D1 / 2 of the width D1 of the step portion S and half the length D2 / 2 of the width D2 of the resolver coil C2 is D2 / 2 + D1 / 2. The width D1 of the step portion S is set such that the total value D2 / 2 + D1 / 2 is less than the arc length R1 (D2 / 2 + D1 / 2 < R1). Also, the width D1 of the step portion S is set such that the width D1 of the step portion S is smaller than the width D2 of the resolver coil C1 (D1 < D2). Due to such dimensional relationships, in the region from the boundary surface G2 of the stator core 10a to the upper surface F of the step portion S in the radial direction, the resolver coils C1 and C2 do not interfere with each other.

[0033] Also, since region A2 is located radially outside region A1, the arc length R2 is larger than the arc length R1. By increasing the radial height HS of the step portion S, it is possible to increase the arc length R2. Region A2 includes the right half of the resolver coil C1 and the left half of the resolver coil C2. The sum of half the length D2 / 2 of the width D2 of the resolver coil C1 and half the length D2 / 2 of the width D2 of the resolver coil C2 is D2. The height HS of the step portion S is set so that the sum value D2 is less than R2 (D2 < R2). As a result, in the region radially outside the upper surface F of the step portion S, the resolver coil C1 and the resolver coil C2 do not interfere with each other.

[0034] In the example shown in FIG. 4, region A2 includes the right half of the resolver coil C1 and the left half of the winding W2 of the resolver coil C2. The sum of half the length D2 / 2 of the width D2 of the resolver coil C1 and half the length D3 / 2 of the left half of the width D3 of the winding W2 of the resolver coil C2 is D2 / 2 + D3 / 2. The height HS of the step portion S may be set so that the sum value D2 / 2 + D3 / 2 is less than R2 (D2 / 2 + D3 / 2 < R2).

[0035] As described above, by providing the step portion S on the first tooth T1 and adjusting the width D1 and the height HS of the step portion S, it is possible to prevent interference between adjacent resolver coils C without increasing the diameter of the stator core 10a.

[0036] In the present embodiment, the radial positions of adjacent resolver coils C are different. However, since the radial height HT of the teeth T on which the resolver coils C are mounted is common, the influence on the detection accuracy of the resolver 100 is sufficiently small even when compared with the case where the radial positions of adjacent resolver coils C are the same.

[0037] As described above, this embodiment provides a stepped portion S on the teeth T of the stator 10, so that the positions of adjacent resolver coils C mounted on the teeth T are different in the radial direction of the stator core 10a, thereby preventing interference between adjacent resolver coils C. This makes it possible to miniaturize the high-resolution resolver 100.

[0038] While embodiments of this disclosure have been described above, it goes without saying that the technical scope of this disclosure should not be interpreted restrictively by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of this disclosure should be determined based on the scope of the invention described in the claims and the scope of its equivalents.

[0039] For example, in the embodiment described above, the resolver coils C are configured to alternately have different radial positions, but the present invention is not limited to this. One first tooth T1 may be arranged in the circumferential direction, followed by two second teeth T2 arranged consecutively. In this case, the radial position of every two resolver coils C will shift radially outward. Thus, the resolver coils C may be configured to have periodically different radial positions. Alternatively, the resolver coils C may be configured to have randomly different radial positions. Furthermore, the radial position of at least one resolver coil C may be configured to be different from the radial position of the other resolver coils. Even with such configurations, it is possible to miniaturize the resolver 100 compared to the case where all resolver coils C have the same radial position.

[0040] Furthermore, in this embodiment, the resolver coil C shown in Figure 3 has windings W1 and W2 wound around coil bobbins BO1 and BO2, but the windings W1 and W2 may also be directly wound around teeth T. Also, if the resolver coil C has windings W1 and W2 directly wound around teeth T, the tip portion located radially outward of teeth T shown in Figure 2 may be a roughly T-shape that is wider in the circumferential direction.

[0041] Furthermore, in this embodiment, the positions of adjacent resolver coils C in the radial direction of the stator core 10a are different. To further reduce the impact of this difference on the detection accuracy of the resolver, the RD converter may correct the output signal from the resolver coil C based on the above difference.

[0042] Furthermore, the RD converter connected to the resolver 100 in the embodiment of this disclosure may process the output signal using an amplitude variation method or a phase variation method.

[0043] Furthermore, although the resolver 100 in the embodiment of this disclosure is of the outer rotor type, it may also be of the inner rotor type. [Explanation of Symbols]

[0044] 10: Status 10a: Stator core T, T1, T2: Teeth C, C1, C2: Resolver Coil S: Stepped section F: Top surface of the stepped section G1: Outer surface G2: Boundary surface Cin: Excitation coil Cout: Output coil L1: 1st lid part L2: 2nd lid part BO1, BO2: core W1, W2: Winding FU1, FU2: First flange FL1, FL2: Second flange B1, B2: Coil bobbins 20: Rotor 100 resolvers

Claims

1. A stator core having multiple teeth that protrude radially and are arranged circumferentially, The set comprises a plurality of coils attached to each of the plurality of teeth, A resolver in which, in the radial direction of the stator core, the position of at least one coil is different from the position of the other coils.

2. The resolver according to claim 1, wherein the plurality of teeth include first teeth having stepped portions for radial positioning of the coil and second teeth not having the stepped portions.

3. The resolver according to claim 2, wherein the first teeth and the second teeth are arranged alternately in the circumferential direction of the stator core.

4. The resolver according to claim 1, wherein the winding specifications of the multiple coils are substantially the same.

5. The resolver according to any one of claims 1 to 4, wherein the resolver is of the outer rotor type.

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