Angle sensor

Abstract

An angle sensor (1) comprises a stator (2). The stator (2) comprises a plurality of protruding parts (10) that protrude inward, and a plurality of coils (3) that surround the plurality of protruding parts (10). The stator (2) comprises a first end part (11) and a second end part (12) in the circumferential direction. The plurality of coils (3) include excitation coils (4), and detection coils (5) that are disposed inward of the excitation coils (4).

Description

Angle sensor

[0001] The present invention relates to an angle sensor, and more particularly to an inductive angle sensor.

[0002] Conventionally, various sensors have been used to detect the rotational angle of a motor or the like. Among such angle sensors for detecting the rotational angle, there is an inductive sensor (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-071340

[0004] The conventional inductive sensor has room for improvement in terms of miniaturization.

[0005] Therefore, an object of the present invention is to provide an angle sensor that can be miniaturized while maintaining detection accuracy.

[0006] An angle sensor according to an aspect of the present invention includes a stator having a plurality of protrusions protruding inward and a plurality of coils surrounding the plurality of protrusions. In the circumferential direction, the stator includes a first end portion and a second end portion, and the plurality of coils include an exciting coil and a detection coil disposed inside the exciting coil.

[0007] According to the present invention, it is possible to provide an angle sensor capable of improving detection accuracy.

[0008] This is a schematic diagram showing the configuration of an angle sensor according to one embodiment of the present invention, and is a partially transparent perspective view showing the internal configuration by passing through a part of the angle sensor. This is a schematic perspective view showing the configuration of the angle sensor. This is a schematic front view showing the configuration of the angle sensor. This is a schematic side view showing the configuration of the angle sensor. This is a schematic perspective view showing the configuration of the stator. This is a schematic front view showing the configuration of the stator. This is a schematic rear view showing the configuration of the stator. This is a schematic side view showing the configuration of the stator. This is a schematic diagram showing the configuration of the stator as seen in the radial direction. This is a schematic diagram showing the configuration of the stator as seen in the radial direction. This is a partially enlarged view showing the part enclosed by frame line A in Figure 6. This is a virtual diagram of the stator as seen from the inner circumference side, showing a stator with multiple protrusions extended so that they are aligned along a plane. This is a schematic diagram showing the configuration of an excitation coil to show an example of an excitation coil pattern. This is a schematic diagram showing the configuration of an excitation coil to show another example of an excitation coil pattern. This is a schematic diagram showing the configuration of a detection coil to show an example of a detection coil pattern.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Note that in the drawings, not all of the multiple components are assigned reference numerals, and the reference numerals of some of the multiple components may be omitted. Figure 1 is a schematic diagram showing the configuration of an angle sensor 1 according to an embodiment of the present invention, and is a partially transparent perspective view that shows the internal configuration by passing through some of the components of the angle sensor 1. Figure 2 is a schematic perspective view showing the configuration of the angle sensor 1, Figure 3 is a schematic front view showing the configuration of the angle sensor 1, and Figure 4 is a schematic side view showing the configuration of the angle sensor 1.

[0010] As shown in Figures 1 to 4, the angle sensor 1 includes a stator 2. The stator 2 includes a plurality of protrusions 10 projecting inward and a plurality of coils 3 surrounding the plurality of protrusions 10. The stator 2 also has a first end 11 and a second end 12 in the circumferential direction. The plurality of coils 3 include an excitation coil 4 and a detection coil 5 arranged inside the excitation coil 4. The configuration of the angle sensor 1 will be described in detail below.

[0011] As shown in Figures 1 to 4, the angle sensor 1 specifically comprises a stator 2 and a rotor 6. In the angle sensor 1, the stator 2 and rotor 6 each extend around an axis x. The rotor 6 has a cylinder 30 and a conductive structure 7 fixed to the cylinder 30. As shown in Figures 2 to 4, in the angle sensor 1, the stator 2 and rotor 6 face each other in the radial direction of the cylinder 30, and the excitation coil 4 and detection coil 5 cover the cylinder 30 from the outside (hereinafter also referred to as the "outer circumference side") in the radial direction. Note that in Figures 2 to 4, the stator 2 and rotor 6 are shown in a predetermined positional relationship. This predetermined positional relationship is an example of the positional relationship between the stator 2 and rotor 6 in the operating state when the angle sensor 1 is attached to the application object. In the angle sensor 1, the rotor 6 is arranged inside the stator 2. Note that axis x is the rotation axis of the angle sensor 1. Also, the radial direction is the direction perpendicular to axis x.

[0012] The cylinder 30 of the rotor 2 is a cylindrical member extending along the axis x, as shown in Figures 1 to 4. In Figure 1, the inside of the cylinder 30 is shown transparently. The cylinder 30 of the rotor 6 is attached to a rotating member of an external device to which the angle sensor 1 is applied, so that the axis x coincides with or approximately coincides with the rotation axis of the rotating member of the external device. For example, as shown in Figures 1 to 4, the cylinder 30 of the rotor 6 has an inner circumferential surface 31, which is a cylindrical surface extending along a cylindrical surface with axis x as the central axis, and an outer circumferential surface 32, which is a cylindrical surface on the outer circumference that faces away from the inner circumferential surface 31. The cylinder 30 also has end faces 33 and 34, which are faces in the respective directions in which the axis x extends. The inner circumferential surface 31 and the outer circumferential surface 32 extend between the end face 33 and the end face 34. The angle sensor 1 is applied to, for example, a motor, in which the motor shaft is passed through the inner circumferential surface 31 of the cylinder 30 of the rotor 6, and the rotor 6 is fixed to the shaft. The cylinder 30 is made of, for example, a resin material, a non-magnetic material, or a non-conductive material. Note that the non-magnetic material may also be non-conductive.

[0013] The conductor structure 7 is formed from conductors, and is composed of a plurality of conductors 8, as shown in Figure 1, for example. The plurality of conductors 8 are arranged in the circumferential direction around an axis x, and as schematically shown in Figure 1, the plurality of conductors 8 form a cylindrical conductor structure 7 that extends in an annular shape around the axis x. The conductors 8 can be any conductive material (a material capable of generating so-called eddy currents or induced currents (electric currents) within one plane), for example, a metal body. The plurality of conductors 8 are arranged at a predetermined distance apart in the circumferential direction of the cylinder 30. That is, two adjacent conductors 8 are separated by a predetermined distance around the axis x and are electrically insulated from each other. The plurality of conductors 8 are arranged at equal or approximately equal angular intervals in the circumferential direction along a cylindrical surface with axis x as the central axis. The plurality of conductors 8 have, for example, a curved shape. The plurality of conductors 8 may be connected to each other. Multiple conductors 8 are connected by one or more connecting parts, and one or more connecting parts may be made of a non-conductive material (e.g., resin) or a conductive material (e.g., metal), and the multiple conductors 8 may be electrically connected.

[0014] Multiple conductors 8 are provided inside the cylinder 30, for example, as shown in Figure 1. The entirety of the conductors 8 may be embedded inside the cylinder 30, or a portion of each conductor 8 may be exposed on the surface of the cylinder 30. Alternatively, the multiple conductors 8 may be attached to the surface of the cylinder 30, for example, the outer circumferential surface 32. In this case, a portion of the conductors 8 may be embedded inside the cylinder 30.

[0015] As shown in Figures 2 to 4, in the angle sensor 1 in use, the rotor 6 is positioned on the inner side (hereinafter also referred to as the "inner circumference side") in the radial direction of the stator 2. Specifically, each of the multiple protrusions 10 faces the outer circumferential surface 32 of the cylinder 30 of the rotor 6 at intervals in the radial direction, and each of the multiple protrusions 10 faces the conductor structure 7 in the radial direction. In addition, the excitation coil 4 and the detection coil 5 face the conductor structure 7 in the radial direction.

[0016] Figure 5 is a perspective view schematically showing the configuration of the stator 2, Figure 6 is a front view schematically showing the configuration of the stator 2, Figure 7 is a rear view schematically showing the configuration of the stator 2, Figure 8 is a side view schematically showing the configuration of the stator 2, and Figures 9 and 10 are schematic diagrams showing the configuration of the stator 2 as seen in the radial direction. For the sake of explanation, one side in the x-axis direction is referred to as the front side, and the other side in the x-axis direction is referred to as the rear side. Also, Figure 9 shows the stator 2 as seen from the inner circumference side, and Figure 10 shows the stator 2 as seen from the other side in the radial direction. Note that the coils 3 (excitation coil 4 and detection coil 5) are not shown in Figures 5 to 10.

[0017] Specifically, as shown in Figures 5 to 10, the stator 2 extends in an arc around the axis x, and extends in an arc between the first end 11 and the second end 12. Also, as shown in Figures 5 and 9, the stator 2 has a first path 13 extending in the direction of the axis x and a second path 14 extending in the direction of the axis x. The excitation coil 4 passes through the first path 13, and the detection coil 5 passes through the second path 14. Furthermore, in the direction in which the multiple protrusions 10 are aligned, the first path 13 is on the side of the first end 11 or the second end 12 relative to the second path 14. For example, as shown in Figures 5 and 9, in the direction in which the multiple protrusions 10 are aligned, the first path 13 and the second path 14 face each other via the protrusions 10. Furthermore, the first path 13 and the second path 14 are specifically, for example, grooves extending in the direction of the axis x. Furthermore, as shown in Figures 5-8 and 10, the stator 2 has a third path 17. The excitation coil 4 and the detection coil 5 pass through the third path 17 in the direction in which the multiple protrusions 10 are aligned.

[0018] As shown in Figures 5 to 10, the multiple protrusions 10 are arranged between the first end 11 and the second end 12 and extend along an arc around axis x. The multiple protrusions 10 are arranged, for example, along a circular arc or a substantially circular arc around axis x. Also, the multiple protrusions 10 are arranged with gaps between them. The multiple protrusions 10 are arranged, for example, at equal or substantially equal angular intervals around axis x.

[0019] The configuration of Stator 2 will be explained in more detail below.

[0020] Specifically, the stator 2 has an arc portion 20 that extends in an arc shape around the axis x, as shown in Figures 5 to 10. The arc portion 20 extends, for example, along a circular arc centered on the axis x, and also extends in the direction of the axis x. The arc portion 20 has, for example, an inner circumferential surface 21 that extends in an arc shape along a cylindrical surface with the axis x as the central axis, and an outer circumferential surface 22 that is a surface on the outer circumferential side that faces away from the inner circumferential surface 21. The arc portion 20 also has end faces 23 and 24 that face the respective directions in which the axis x extends. The inner circumferential surface 21 and the outer circumferential surface 22 extend between the end faces 23 and 24. The inner circumferential surface 21, for example, in a cross-section with a plane perpendicular to the axis x, draws a circular arc or a substantially circular arc centered on the axis x. Similarly, the outer surface 22, for example, in a cross-section defined by a plane perpendicular to the axis x, traces a circular arc or a nearly circular arc centered on the axis x.

[0021] As shown in Figures 5 to 8, the multiple protrusions 10 project inward from the inner circumferential surface 21 of the arc portion 20 and are aligned along the inner circumferential surface 21 of the arc portion 20. Each of the multiple protrusions 10 has, for example, a spoke 15 and a wall 16, as shown in Figures 5 to 8. The spoke 15 is the portion that projects radially inward from the inner circumferential surface 21 of the arc portion 20. The wall 16 is the portion connected to the inner end of the spoke 15. The shape of the cross-section of the spoke 15 by a plane perpendicular to the radial direction is, for example, rectangular or substantially rectangular. The shape of the wall 16 viewed radially is, for example, rectangular or substantially rectangular, and the wall 16 is, for example, a plate-shaped portion curved in an arc.

[0022] Figure 11 is a magnified view of the portion enclosed by frame line A in Figure 6. As shown in Figures 6, 7, and 11, the spoke 15 has a pair of side surfaces 15a and 15b that face away from each other in the circumferential direction, and a pair of side surfaces 15c and 15d that face away from each other in the axial x direction. Side surfaces 15a to 15d extend, for example, along a plane. Also, as shown in Figures 6, 7, and 11, the wall 16 has a pair of side surfaces 16a and 16b that face away from each other in the circumferential direction, and a pair of side surfaces 16c and 16d that face away from each other in the axial x direction. Side surfaces 16a to 16d extend, for example, along a plane.

[0023] As shown in Figures 6, 7, and 11, in each projection 10, the sides 15a and 15b of the spoke 15 and the sides 16a and 16b of the wall 16 are connected to each other, forming the sides 10a and 10b of the projection 10. For example, in each projection 10, the sides 15a and 15b of the spoke 15 and the sides 16a and 16b of the wall 16 are connected to each other flush or substantially flush. The sides 10a and 10b extend, for example, along a plane. On the other hand, as shown in Figures 6, 7, and 11, in each projection 10, the sides 16c and 16d of the wall 16 protrude further away from the spoke 15 in the axial x direction than the sides 15c and 15d of the spoke 15. Therefore, in each protrusion 10, the wall 16 has wall surfaces 16e and 16f that extend between the sides 16c and 16d and the sides 15c and 15d, respectively, and face the outer periphery, as shown in Figures 6-8, 10 and 11. As a result, in each protrusion 10, a step is formed between the sides 15c and 15d of the spoke 15 and the sides 10c and 10d of the wall 16. The wall surfaces 16e and 16f each become the inner circumferential walls with respect to the sides 15c and 15d of the spoke 15.

[0024] As shown in Figures 5-8 and 11, for example, the sides 15c and 15d of each spoke 15 are located on the interior side of the spoke 15 in the axial x direction, relative to the end faces 23 and 24 of the arc portion 20. As a result, in each protrusion 10, a recess is formed between the wall 16 and the arc portion 20, recessing inward towards the spoke 15 in the axial x direction. Therefore, on the front and rear sides of the stator 2, a groove extending intermittently in an arc shape is formed between the wall 16 and the arc portion 20 of each of the multiple protrusions 10. This intermittently extending groove forms the third path 17 described above. Note that each of the multiple protrusions 10 does not necessarily have to form the aforementioned recess. For example, the sides 15c and 15d of the multiple spokes 15 may be flush with the end faces 23 and 24 of the arc portion 20, or they may protrude toward the sides 16c and 16d of the wall 16 in the axial x direction, relative to the end faces 23 and 24 of the arc portion 20. In this case as well, a groove or recess extending intermittently in an arc shape is formed to form the third path 17.

[0025] As described above, the multiple protrusions 10 are arranged with space between them. As shown in Figure 11, in two adjacent protrusions 10, the side surface 10a of one protrusion 10 faces the side surface 10b of the other protrusion 10 and forms a groove 25 extending in the axial x direction. The groove 25 is recessed on the outer circumference. In the stator 2, one or more grooves 25 are formed. The second path 14 through which the detection coil 5 described above passes is formed by the groove 25.

[0026] Furthermore, as shown in Figures 6, 7, and 9, the side surface 10a of the projection 10 adjacent to the first end 11 among the multiple projections 10 is exposed in the circumferential direction and does not form a groove 25. Between the side surface 10a of the projection 10 adjacent to the first end 11 and the inner circumferential surface 21 of the arc portion 20, a stepped portion 26a is formed, which creates a step that is recessed toward the outer circumference. Similarly, the side surface 10b of the projection 10 adjacent to the second end 12 among the multiple projections 10 is exposed in the circumferential direction and does not form a groove 25. Between the side surface 10b of the projection 10 adjacent to the second end 12 and the inner circumferential surface 21 of the arc portion 20, a stepped portion 26b is formed, which creates a step that is recessed toward the outer circumference. The first path 13 through which the excitation coil 6 described above passes is formed by the stepped portions 26a and 26b.

[0027] As shown in Figures 5 to 10, the stator 2 has, for example, six protrusions 10. For the sake of explanation, the six protrusions 10 will be numbered sequentially from the first end 11 to the second end 12, and referred to as the 1st to 6th protrusions 10. Also, as an example, the six protrusions 10 are arranged at equal or approximately equal angular intervals around the axis x, and the circumferential widths of the multiple protrusions 10 are the same or approximately the same, and the circumferential widths of the multiple grooves 25 are the same or approximately the same. The circumferential width of each protrusion 10 and the circumferential width of each groove 25 are set by the axis doubling angle of the angle sensor 1. For example, if the axis doubling angle of the angle sensor 1 is 4X, the circumferential width of each protrusion 10 and the circumferential width of each groove 25 are set so that the central angle around the axis x of the circumferential width of the multiple protrusions 10 surrounded by the detection coil 5 is 90° or approximately 90°. Furthermore, for example, if the axis multiplication angle of the angle sensor 1 is 3X, the circumferential width of each protrusion 10 and the circumferential width of each groove 25 are set such that the central angle around the axis x of the circumferential width of the multiple protrusions 10 surrounded by the detection coil 5 is 120° or approximately 120°. As an example, the axis multiplication angle of the angle sensor 1 is set to 4X.

[0028] Figure 12 is a hypothetical view of the stator 2 as seen from the inner circumference, and shows the stator 2 with multiple protrusions 10 extended so as to be aligned along a plane. As shown in Figures 9 and 12, two first paths 13 are formed, with the stepped portion 26a formed by the first protrusion 10 and the stepped portion 26b formed by the sixth protrusion 10 each forming the first path 13. Also, for example, two second paths 14 are formed, with the groove 25 between the first protrusion 10 and the second protrusion 10 and the groove 25 between the fifth protrusion 10 and the sixth protrusion 10 each forming the second path 14.

[0029] The excitation coil 4 is formed to surround the first to sixth protrusions 10. The circumferential ends 4a and 4b of the excitation coil 4 (hereinafter referred to as "circumferential ends") each pass through the first path 13. The detection coil 5 is positioned inside the excitation coil 4 and is formed to surround the second to fifth protrusions 10. The circumferential ends 5a and 5b of the detection coil 5 (hereinafter referred to as "circumferential ends") each pass through the second path 14. In this way, in the circumferential direction where the first to sixth protrusions 10 are lined up, the first path 13 is on the side of the first end 11 or the second end 12 relative to the second path 14. Furthermore, in the circumferential direction, one adjacent first path 13 and the second path 14 face each other via the first protrusion 10, and the other adjacent first path 13 and the second path 14 face each other via the sixth protrusion 10. Thus, the peripheral ends 4a and 4b on both sides of the excitation coil 4 are separated in the circumferential direction from the peripheral ends 5a and 5b on both sides of the detection coil 5, and are also separated from the side away from the detection coil 5. The specific configurations of the excitation coil 4 and the detection coil 5 will be described later.

[0030] Furthermore, as shown in Figures 5 to 7, the stator 2 has multiple mounting portions 27 which are parts that are attached to external devices that are the target of application. For example, the multiple mounting portions 27 are arranged on the first end 11 side and the second end 12 side, respectively. Specifically, for example, the multiple mounting portions 27 are arranged on the first end 11 side and the second end 12 side, respectively, with respect to the holding portion 28, which is a radially extending portion described later. As an example, the stator 2 has two mounting portions 27. As shown in Figures 5 to 7, the two mounting portions 27 are arranged on the first end 11 side and the second end 12 side, respectively, in the circumferential direction where the protruding portions 10 are aligned. The mounting portions 27 are provided, for example, on the outer circumferential surface 22 of the arc portion 20 and protrude outward from the arc portion 20. The mounting portions 27 also have through holes 27a through which fixing members such as bolts are passed, and the mounting portions 27 can be attached to external devices by fixing members. Furthermore, the number of mounting portions 27 on the stator 2 is not limited to two.

[0031] Furthermore, as shown in Figures 5-8 and 10, the stator 2 includes a holding portion 28 that extends radially between the first end 11 and the second end 12 in the circumferential direction where multiple protrusions 10 are arranged. The holding portion 28 is the part to which a substrate having a circuit section and a calculation section (hereinafter referred to as an electrical circuit board) is fixed. The excitation coil 4 and the detection coil 5 are electrically connected to this electrical circuit board. The holding portion 28 protrudes outward from the outer circumferential surface 22 of the arc portion 20, for example. The holding portion 28 also has a housing portion 28a that extends in the axial x direction. The housing portion 28a is a frame-shaped portion that defines a space for housing the electrical circuit board, as shown in Figures 6, 7, and 10, for example. The housing portion 28a has a structure such that the electrical circuit board slides into the space. Note that the housing portion 28a is not limited to a frame shape. The housing portion 28a may be, for example, a plate-shaped structure formed to securely hold an electrical circuit board. The electrical circuit board housed in the housing portion 28a is secured, for example, by an adhesive. The electrical circuit board may also be a flexible substrate and may have a portion for receiving or transmitting communications.

[0032] Furthermore, as shown in Figures 5, 6, and 8, the arc portion 20 has, for example, a boss 29 extending from the end face 23 in the axial x direction. The boss 29 is a portion that protrudes from the end face 23. There may be multiple bosses 29, or only one. As will be described later, the wires of the excitation coil 4 and the detection coil 5 pass between the boss 29 and the protruding portion 10, and the wires of the excitation coil 4 and the detection coil 5 intersect between the boss 29 and the protruding portion 10. In addition, the direction in which the wires are drawn out may be changed by making contact with or hooking the wires onto the boss 29.

[0033] The multiple protrusions 10 and arc portions 20 of the stator 2 having the above-described configuration are integrally molded from the same material, for example, and each component of the multiple protrusions 10 and arc portions 20 is integrally connected. The multiple protrusions 10 and arc portions 20 are insulating members, for example, made of resin. The multiple protrusions 10 and arc portions 20 are made of, for example, resin material, non-magnetic material, non-conductive material, etc. Note that the non-magnetic material may also be non-conductive. Note that any or all of the components of the multiple protrusions 10 and arc portions 20 may be formed as separate parts. In this case, the components formed as separate parts are assembled by adhesive or the like to form the multiple protrusions 10 and arc portions 20.

[0034] Next, the configurations of the excitation coil 4 and the detection coil 5 will be explained in more detail.

[0035] As shown in Figures 1-4 and 12, the excitation coil 4 and the detection coil 5 each extend in an arc shape along an annular surface around axis x. For example, the excitation coil 4 and the detection coil 5 each extend in an arc shape or substantially arc shape along a cylindrical surface with axis x as the central axis. As shown in Figures 1-4 and 12, the excitation coil 4 and the detection coil 5 are formed by winding a conductive member around a plurality of protrusions 10. The conductive member forming the excitation coil 4 and the detection coil 5 is covered with, for example, an insulating material (insulating film or coating) and is electrically insulated from the outside. The conductive member forming the excitation coil 4 and the detection coil 5 is, for example, a magnet wire. As an example, the conductive member forming the excitation coil 4 and the detection coil 5 is a magnet wire. However, the conductive member forming the excitation coil 4 and the detection coil 5 is not limited to a magnet wire.

[0036] The excitation coil 4 and the detection coil 5 each have a predetermined pattern. The magnet wire is wound around the multiple protrusions 10 such that it passes through a specific path extending around the multiple protrusions 10, thereby making the excitation coil 4 and the detection coil 5 each coil having a predetermined pattern. This specific path is a path along one of the grooves 25, stepped portions 26, and wall surfaces 16e, 16f of the protrusions 10, which are portions of each protrusion 10 or portions formed by the protrusions 10 individually or in combination. This specific path includes a first path 13, a second path 14, and a third path 17.

[0037] Figure 13 is a schematic diagram illustrating the configuration of an excitation coil 4 to show an example of the excitation coil 4 pattern (hereinafter also referred to as the "first pattern"). As shown in Figure 13, the excitation coil 4 surrounds the six protrusions 10 between the first protrusion 10 and the sixth protrusion 10. Specifically, both ends of the excitation coil 4 in the circumferential direction pass through the first path 13 along the stepped portion 26a of the first protrusion 10 and the first path 13 along the stepped portion 26b of the sixth protrusion 10, respectively. The front end of the excitation coil 4 passes through the third path 17, which is a path along the wall surface 16e of each of the protrusions 10 from the first protrusion 10 to the sixth protrusion 10. The rear end of the excitation coil 4 also passes through the third path 17, which is a path along the wall surface 16f of each of the protrusions 10 from the first protrusion 10 to the sixth protrusion 10. Furthermore, the two ends 4c and 4d of the excitation coil 4 extend away from the protruding portion 10. Note that the ends 4c and 4d are the portions that include the terminals of the excitation coil 4.

[0038] Figure 14 is a schematic diagram showing the configuration of an excitation coil 4 to illustrate another example of the excitation coil 4 pattern (hereinafter also referred to as the "second pattern"). The excitation coil 4 of the second pattern shown in Figure 14 is equivalent to the excitation coil 4 of the first pattern shown in Figure 13 in terms of magnetic flux formation. As shown in Figure 14, the excitation coil 4 surrounds the six protrusions 10 between the first protrusion 10 and the sixth protrusion 10, similar to the first pattern. However, unlike the first pattern, the magnet wire is wound sequentially around each protrusion 10 in the circumferential direction to surround the six protrusions 10 between the first protrusion 10 and the sixth protrusion 10. Also, as shown in Figure 14, similar to the first pattern, both circumferential ends of the excitation coil 4 of the second pattern pass through the first path 13 along the stepped portion 26a of the first protrusion 10 and the first path 13 along the stepped portion 26b of the sixth protrusion 10, respectively.

[0039] Specifically, for example, as shown in Figure 14, the magnet wire 41 passes through one of the grooves 25 and is wound around each projection 10 from one of the wall surfaces 16e and 16f in order from the groove 25 to the first path 13 on one side in the circumferential direction. Next, the magnet wire 41 is reversed through the first path 13 on one side in the circumferential direction and is wound around each projection 10 from the other side of the wall surface 16e and 16f in order to the first path 13 on the other side in the circumferential direction. Next, the magnet wire 41 is reversed through the first path 13 on the other side in the circumferential direction and is wound around each projection 10 from one of the wall surfaces 16e and 16f in order to the groove 25 through which it was first passed toward one side in the circumferential direction. Then, the magnet wire is pulled out through this groove 25 in a direction away from the projection 10. This forms the second pattern of excitation coil 4. In the second pattern of excitation coil 4, the two ends 4c, 4c also extend in a direction away from the protruding portion 10.

[0040] As shown in Figure 14, in the second pattern of excitation coil 4, the portion 42 wound around each protrusion 10 from the wall surface 16e (hereinafter referred to as the "front portion") is connected in series in the circumferential direction on the front side, and the portion 43 wound around each protrusion 10 from the wall surface 16f (hereinafter referred to as the "back portion") is connected in series in the circumferential direction on the back side. The front portion 42 or back portion 43 of the excitation coil 4 has ends 4c and 4d, and the portions wound around the protrusions 10 that straddle the groove 25 through which the ends 4c and 4d pass are not connected. In the example in Figure 14, the ends 4c and 4d are pulled out from the back side through the groove 25 between the third protrusion 10 and the fourth protrusion 10, and the back portion 43 of the excitation coil 4 is insulated between the portion wound around the third protrusion 10 and the portion wound around the fourth protrusion 10.

[0041] As shown in Figure 14, in the groove 25, the front portions 42 of the excitation coil 4 wound around two adjacent protrusions 10 on either side of the groove 25 face each other, but the direction of extension of the excitation coil 4 in each of these front portions 42 is opposite to that of the excitation coil 4. Similarly, as shown in Figure 14, in the groove 25, the back portions 43 of the excitation coil 4 wound around two adjacent protrusions 10 on either side of the groove 25 face each other, but the direction of extension of the excitation coil 4 in each of these back portions 43 is opposite to that of the excitation coil 4. The extension direction of the excitation coil 4 is from one end 4c, 4d to the other end 4c, 4d.

[0042] When current flows through the excitation coil 4, in the third path 17 along the front wall surface 16e, a current flows through the front portion 42 and the back portion 43 of the excitation coil 4 in one direction in the circumferential direction, and in the third path 17 along the back wall surface 16f, a current flows through the front portion 42 and the back portion 43 of the excitation coil 4 in the other direction in the circumferential direction. Also, in the first path 13, current flows in the same direction through the front portion 42 and the back portion 43 of the excitation coil 4. Therefore, by flowing current through the excitation coil 4, a periodically changing magnetic flux can be generated in the excitation coil 4 in the third path 17 along the front wall surface 16e, the third path 17 along the back wall surface 16f, and the path surrounding the six protrusions 10 formed by the first path 13. On the other hand, as shown in Figure 14, in the groove 25, currents flow in opposite directions along the axis x through the respective portions of the front portion 42 of the excitation coil 4 that are facing each other. Similarly, in the groove 25, currents flow in opposite directions along the axis x to each of the opposing back portions 43 of the excitation coil 4. As a result, in the groove 25, magnetic fluxes in opposite directions are generated in each of the front portions 42 of the excitation coil 4, and the generated magnetic fluxes cancel each other out. Similarly, in the groove 25, magnetic fluxes in opposite directions are generated in each of the back portions 43 of the excitation coil 4, and the generated magnetic fluxes cancel each other out. Therefore, in terms of magnetic flux formation, the second pattern of excitation coil 4 forms an excitation circuit that is substantially equivalent to the first pattern of excitation coil 4 shown in Figure 13.

[0043] As shown in Figures 1-4 and 12, the detection coil 5 has a plurality of coil pieces 50 arranged in the direction in which the detection coil 5 extends. The coil pieces 50 have a shape that encloses a space and are the part of the detection coil 5 that extends in an annular manner around a radially extending line. The coil pieces 50 have a shape such that the space enclosed by the coil pieces 50 follows an annular plane around the axis x. Also, as shown in Figures 1-4 and 12, the stator 2 has two detection coils 5A and detection coil 5B as the detection coil 5. The number of coil pieces 50 in the detection coil 5 corresponds to the axis double angle set in the angle sensor 1. The number of detection coils 5 also corresponds to the number of detection signals output from the angle sensor 1.

[0044] The detection coil 5A and the detection coil 5B overlap in the radial direction. The detection coil 5A and the detection coil 5B are such that a part of the space surrounded by the coil piece 50 of the detection coil 5A and a part of the space surrounded by the coil piece 50 of the detection coil 5B are displaced in the circumferential direction, and another part of the space surrounded by the coil piece 50 of the detection coil 5A and another part of the space surrounded by the coil piece 50 of the detection coil 5B overlap in the circumferential direction. Specifically, the space surrounded by the coil piece 50 of the detection coil 5A is located at a position displaced from the space surrounded by the coil piece 50 of the detection coil 5B by half the width of the space surrounded by the coil piece 50 of the detection coil 5A in the circumferential direction.

[0045] A magnet wire is wound around each of the protrusions 10, and multiple annular coil pieces 50 are formed in the circumferential direction by passing through a third path 17 on the front side along the wall surface 16e, a groove 25, and a third path 17 on the back side along the wall surface 16f, thereby forming a detection coil 5 on the stator 2. For example, the detection coil 5 is formed by a single magnet wire passing through a groove 25 selected from a plurality of grooves 25. Specifically, for example, the magnet wire is passed alternately through the front third path 17 along the wall surface 16e and the back third path 17 along the wall surface 16f for each of two adjacent protrusions 10 toward one side in the circumferential direction, and also through the groove 25 alternately from the front and back sides for each of two adjacent protrusions 10, and then folded back after passing through the groove 25 that forms the second path 14 on one side in the circumferential direction, and similarly passed through the front third path 17, the back third path 17 and the groove 25 toward the other side in the circumferential direction until reaching the groove 25 that forms the second path 14 on the other side in the circumferential direction, thereby forming the detection coil 5. In this case, each coil piece 50 is formed around two protrusions 10. Also, the coil piece 50 of detection coil 5A and the coil piece 50 of detection coil 5B are offset by one protrusion 10 in the circumferential direction. Furthermore, each coil piece 50 is not limited to being formed around two protrusions 10, but may be formed around a different number of protrusions 10. Also, although the case of winding the magnet wire around once has been described, the winding configuration of the magnet wire is not limited to this and may be wound around two or more times. In other words, the detection coil 5 formed by winding the magnet wire may have multiple layers, such as two, three, four, or five layers, in addition to one layer in the radial direction. A larger number of turns or layers can amplify the output signal or the detected signal (e.g., the amplitude of the signal waveform).

[0046] Figure 15 is a schematic diagram showing the configuration of a detection coil 5 to illustrate an example of the pattern of the detection coil 5. The detection coils 5A and 5B are formed by winding a magnet wire 45 around a plurality of protrusions 10. As shown in Figure 15, the detection coils 5A and 5B each surround four protrusions 10 between the second protrusion 10 and the fifth protrusion 10. Specifically, both circumferential ends of the detection coils 5A and 5B pass through the second path 14 formed by the groove 25 between the first protrusion 10 and the second protrusion 10, and the second path 14 formed by the groove 25 between the fifth protrusion 10 and the sixth protrusion 10, respectively. Furthermore, the detection coils 5A and 5B are each formed along the protrusions 10 between the second protrusion 10 and the fifth protrusion 10 such that two coil pieces 50 surrounding two protrusions 10 are formed, or substantially two coil pieces 50 surrounding two protrusions 10 are formed.

[0047] The peripheral ends 5a and 5b of the detection coils 5A and 5B, respectively, pass through the second path 14, and the detection coils 5A and 5B are located inward in the circumferential direction compared to the peripheral ends 4a and 4b of the excitation coil 4. Also, as shown in Figure 12, the peripheral end 5a of the detection coils 5A and 5B faces the peripheral end 4a of the excitation coil 4 in the circumferential direction via a single protrusion (first protrusion) 10. Similarly, the peripheral end 5b of the detection coils 5A and 5B faces the peripheral end 4b of the excitation coil 4 in the circumferential direction via a single protrusion (sixth protrusion) 10. In this way, the peripheral ends 5a and 5b of the detection coils 5A and 5B, respectively, are separated from the peripheral ends 4a and 4b of the excitation coil 4 in the circumferential direction.

[0048] Specifically, for example, as shown in FIG. 15, the detection coil 5A has a coil piece 51 surrounding the second protrusion 10 and the third protrusion 10, and a coil piece 52 surrounding the fourth protrusion 10 and the fifth protrusion 10. A peripheral end portion 5a is formed on the coil piece 51, and the coil piece 51 passes through the second path 14 formed by the groove 25. Also, a peripheral end portion 5b is formed on the coil piece 52, and the coil piece 52 passes through the second path 14 formed by the groove 25. Specifically, for example, as shown in FIG. 15, the detection coil 5B has a coil piece 53 surrounding the second protrusion 10, a coil piece 54 surrounding the third protrusion 10 and the fourth protrusion 10, and a coil piece 55 surrounding the fifth protrusion 10. In the detection coil 5B, the coil piece 53 and the coil piece 55 substantially form one coil piece. A peripheral end portion 5a is formed on the coil piece 53, and the coil piece 53 passes through the second path 14 formed by the groove 25. Also, a peripheral end portion 5b is formed on the coil piece 55, and the coil piece 55 passes through the second path 14 formed by the groove 25. The coil piece 50 of the detection coil 5A and the coil piece 50 of the detection coil 5B are offset by only one protrusion 10 in the circumferential direction.

[0049] Also, the two end portions 5c and 5d of each of the detection coils 5A and 5B extend in a direction away from the protrusion 10. For example, as shown in FIG. 15, the end portions 5c and 5d of the detection coil 5A are drawn out from the third path 17 on the back side of one coil piece 50. Similarly, the end portions 5c and 5d of the detection coil 5B are drawn out from the third path 17 on the back side of any one coil piece 50. Note that the end portions 5c and 5d are portions including the terminals of the detection coil 5. The end portions 5c and 5d are drawn out as lead wires, and are drawn out from the vicinity of the third protrusion 10 and the fourth protrusion 10 located at the center portion among the six protrusions 10 in this example. Thereby, the length of the lead wire to the substrate fixed to the holding portion 28 can be shortened.

[0050] Furthermore, as mentioned above, as an example, the axis multiplication angle of the angle sensor 1 is 4X, and the circumferential width of each protrusion 10 and the circumferential width of each groove 25 are set so that the central angle around the axis x of the circumferential width of the four protrusions 10 of the second to fourth protrusions 10 surrounded by the detection coil 5 is 90° or approximately 90°. Note that if the axis multiplication angle of the angle sensor 1 is different, this central angle will be the angle corresponding to the set axis multiplication angle.

[0051] The stator 2 and rotor 6 form an inductive angle sensor. A magnetic space or magnetic gap is formed between the stator 2 and rotor 6. For example, in the angle sensor 1, multiple detection coils 5 are subjected to radially directed magnetic flux of periodically changing magnitude. Specifically, for example, the excitation coil 4 generates a periodically changing magnetic flux that acts on each of the multiple coil pieces 50 of each detection coil 5. On the other hand, the multiple conductors 8 are arranged in the circumferential direction around the axis x as described above, and cross the magnetic flux generated by the excitation coil 4 as the rotor 6 rotates. Also, the projection of the conductor 8, which has a portion extending along the axis x, onto the coil pieces 50 in the radial direction moves as the rotor 6 rotates. Therefore, the magnetic flux from the excitation coil 4 acting on each of the multiple coil pieces 50 cancels out due to the influence of eddy currents generated in the conductors 8, and changes periodically as the rotor 6 rotates. As a result, in multiple coil pieces 50, an electromotive force is generated by electromagnetic induction that changes with the rotation of the rotor 6, and signals that change with the rotation of the rotor 6 are detected from the detection coils 5A and 5B. Based on these detection signals from the detection coils 5A and 5B, the rotation angle of the rotor 6 is detected in an external electrical circuit device.

[0052] The angle sensor 1 has the configuration described above, with the detection coil 5 located inside the excitation coil 4. The peripheral ends 4a and 4b of the excitation coil 4 pass through the first path 13, and the peripheral ends 5a and 5b of the detection coil 5 pass through the second path 14, which is located inside the first path 13 in the circumferential direction. Thus, the detection coil 5 is located inside the peripheral ends 4a and 4b of the excitation coil 4 in the circumferential direction, and the peripheral ends 5a and 5b of the detection coil 5 are separated from the peripheral ends 4a and 4b of the excitation coil 4. Therefore, the magnetic field formed by the excitation coil 4 acting on the detection coil 5 can be stabilized. This allows for miniaturization of the angle sensor 1 while maintaining its detection accuracy.

[0053] Furthermore, the stator 2 is arc-shaped, which allows for a smaller stator 2. This also allows for a smaller angle sensor 1. In addition, the cost of the angle sensor 1 can be reduced.

[0054] Furthermore, the excitation coil 4 and the detection coil 5 can be formed using insulating materials for conductive components such as magnet wires. Therefore, even if there are overlapping portions in the excitation coil 4 and the detection coil 5, the intended electrical path can be maintained. This allows the patterns of the excitation coil 4 and the detection coil 5 to have portions that pass through the same path, thereby enabling miniaturization of the angle sensor 1.

[0055] Thus, according to the angle sensor 1 of the present invention, miniaturization is possible while maintaining detection accuracy.

[0056] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0057] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, and sizes, are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not contradict each other in a technical sense. In addition, each configuration can be selectively combined as appropriate to achieve at least some of the problems and effects described above.

[0058] For example, the configuration of the excitation coil 4 is not limited to the configuration described above. The magnet wire 41 may be wound around a plurality of protrusions 10 in a different form to form the excitation coil 4 so as to have the function of the excitation coil 4 described above, or a function similar to the function of the excitation coil 4 described above. Similarly, the configuration of the detection coil 5 is not limited to the configuration described above. The magnet wire 45 may be wound around a plurality of protrusions 10 in a different form to form the detection coil 5 so as to have the function of the detection coil 5 described above, or a function similar to the function of the detection coil 5 described above. Furthermore, the configuration of the plurality of protrusions 10 of the stator 2 is not limited to the configuration described above. The plurality of protrusions 10 may be formed in a different form so as to have the function of the angle sensor 1 described above, or a function similar to the function of the angle sensor 1 described above. For example, in the detection coil 5B, one coil piece 50 may be formed on the third and fourth protrusions 10, and one coil piece 50 may be formed on the fifth and sixth protrusions 10. In this case, for example, the stator 2 has a seventh protrusion 10 adjacent to the sixth protrusion 10, and the first path 13 is formed in the stepped portion 26b of the seventh protrusion 10. Also, the detection coil 5 and the excitation coil 4 may face each other in the circumferential direction via a plurality of protrusions 10.

[0059] Furthermore, for example, the detection coil 5 may have two or more coil pieces 50. For example, the detection coil 5 may have four coil pieces 50. In this case, at the set axis double angle, one detection coil 5 can output multiple detection signals during one rotation of the rotor 6, which can correct for variations in the detection signals and improve the detection accuracy of the angle sensor 1.

[0060] Furthermore, the configuration forming the first path 13 is not limited to the protruding portion 10, but may also be a configuration that protrudes from the inner circumferential surface 21 of the other arc portion 20. Also, the protruding portion 10 forming the first path 13 does not have to be the same as the other protruding portions 10. For example, the circumferential width of the protruding portion 10 forming the first path 13 does not have to be the same as the circumferential width of the other protruding portions 10.

[0061] 1 Angle sensor, 2 Stator, 3 Coil, 4 Excitation coil, 4a, 4b Peripheral end, 4c, 4d End, 5, 5A, 5B Detection coil, 5a, 5b Peripheral end, 5c, 5d End, 6 Rotor, 7 Conductor structure, 8 Conductor, 10 Protrusion, 10a, 10b, 10c, 10d Side, 11 First end, 12 Second end, 13 First path, 14 Second path, 15 Spoke, 15a, 15b, 15c, 15d Side, 16 Wall, 16a, 16b, 16c, 16d Side, 16e, 16f Wall surface, 17 Third path, 20 Arc section, 21 Inner circumferential surface, 22 Outer circumferential surface, 23, 24 End face, 25 Groove, 26a, 26b Stepped section, 27 Mounting section, 27a 28 Through hole, 28 Holding part, 28a Housing part, 29 Boss, 30 Tube, 31 Inner circumferential surface, 32 Outer circumferential surface, 33, 34 End faces, 41, 45 Magnet wire, 42 Front part, 43 Back part, 50, 51, 52, 53, 54, 55 Coil piece, x axis

Claims

1. An angle sensor comprising a stator having a plurality of protrusions projecting inward and a plurality of coils surrounding the plurality of protrusions, wherein in the circumferential direction, the stator has a first end and a second end, and the plurality of coils include an excitation coil and a detection coil disposed inside the excitation coil.

2. The angle sensor according to claim 1, wherein the excitation coil passes through a first path extending in the direction of the rotation axis, the detection coil passes through a second path extending in the direction of the rotation axis, and in the direction in which the plurality of protrusions are aligned, the first path is located on the first end or the second end side with respect to the second path.

3. The angle sensor according to claim 2, wherein in the direction in which the plurality of protrusions are aligned, the first path and the second path face each other via the protrusions.

4. The angle sensor according to claim 2 or 3, wherein the first path and the second path are grooves extending in the direction of the rotation axis.

5. The angle sensor according to any one of claims 1 to 4, wherein the stator has a portion extending radially between the first end and the second end in the direction in which the plurality of protrusions are aligned, a substrate is fixed to the radially extending portion, and the coil is electrically connected to the substrate.

6. The angle sensor according to any one of claims 1 to 5, wherein the stator has a plurality of mounting portions arranged on the first end side and the second end side, respectively, in the direction in which the protrusions are aligned.

7. The angle sensor according to any one of claims 1 to 6, wherein the stator has a surface facing in the direction of the rotation axis, and has a boss extending from the surface in the direction of the rotation axis, the wires of the plurality of coils pass between the boss and the protrusion in the radial direction, and the wires of the plurality of coils intersect between the boss and the protrusion.

8. An angle sensor according to any one of claims 1 to 7, comprising a rotor on which a metal body is fixed, wherein the metal body and the coil face each other in the radial direction.

9. The angle sensor according to any one of claims 1 to 8, wherein the plurality of coils are formed by winding a magnet wire.

10. The angle sensor according to any one of claims 1 to 8, wherein a third path is formed in the stator through which the excitation coil and the detection coil pass in the direction in which the plurality of protrusions are aligned.

Images