Angle sensor and rotary apparatus

Abstract

[Problem] To provide an angle sensor capable of suppressing the influence of movement in an axial direction of a rotary shaft. [Solution] An angle sensor 1 comprises a rotor 2 and a stator 3. The rotor 2 includes a cylinder 10 and a plurality of metal bodies 20 fixed to the cylinder 10. The stator 3 includes a plurality of protruding portions 30 that protrude toward the rotor 2, and a plurality of coils 40 that surround the plurality of protruding portions 30. The plurality of metal bodies 20 are located inside the cylinder 10.

Description

Angle sensors and rotating devices

[0001] The present invention relates to an angle sensor and a rotating device, and more particularly to an inductive angle sensor and a rotating device equipped with an inductive angle sensor.

[0002] Conventionally, various sensors have been used to detect the rotation angle of a motor, etc. An inductive sensor is one of such angle sensors for detecting the rotation angle (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-200106

[0004] Conventional inductive sensors have room for improvement in terms of detection accuracy.

[0005] Therefore, an object of the present invention is to provide an angle sensor and a rotating device that can improve detection accuracy.

[0006] An angle sensor according to one aspect of the present invention comprises a rotor having a tube and a plurality of metal bodies fixed to the tube, and a stator having a plurality of protrusions protruding toward the rotor and a plurality of coils surrounding the plurality of protrusions, wherein the plurality of metal bodies are located inside the tube.

[0007] 12 is a front view of a rotor according to a modified example of the angle sensor; FIG. 13 is a front view of a rotor according to another modified example of the angle sensor; FIG. 14 is a perspective view of a rotating device to which an angle sensor can be applied; FIG. 15 is a perspective view of a rotating device shown in FIG. 14, the perspective view showing the tip of a rotating shaft in the rotating device shown in FIG. 14, and the vicinity thereof; FIG. 16 is a perspective view of a rotor of a modified example of the angle sensor; FIG. 10 is a perspective view showing a modified example of the stator.

[0008] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that in the drawings, not all of the components are designated by reference numerals, and the reference numerals of some of the components may be omitted. FIG. 1 is a diagram schematically illustrating the configuration of an angle sensor 1 according to an embodiment of the present invention, and is a transparent perspective view schematically illustrating the internal configuration by seeing through some of the components of the angle sensor 1. FIG. 2 is a perspective view schematically illustrating the configuration of the angle sensor 1, FIG. 3 is a front view schematically illustrating the configuration of the angle sensor 1, and FIG. 4 is a side view schematically illustrating the configuration of the angle sensor 1. As shown in FIGS. 1 to 4, the angle sensor 1 includes a rotor 2 and a stator 3. The rotor 2 includes a cylinder 10 and multiple metal bodies 20 serving as conductors fixed to the cylinder 10. The stator 3 includes multiple protrusions 30 protruding toward the rotor 2 and multiple coils 40 surrounding the multiple protrusions 30. The multiple metal bodies 20 are located inside the cylinder 10. The configuration of the angle sensor 1 will be described in detail below. 2 to 4, the rotor 2 and the stator 3 are shown in a predetermined positional relationship. This predetermined positional relationship is an example of the positional relationship between the rotor 2 and the stator 3 when the angle sensor 1 is attached to an application object and in use. In the angle sensor 1, the rotor 2 is disposed inside the stator 3.

[0009] As shown in FIGS. 1 to 3 , the metal bodies 20 as multiple conductors are arranged in the circumferential direction around the axis x. The conductors may be metal bodies or components having conductive members (components capable of generating so-called eddy currents or induced currents (electric currents) within one surface), and a metal body will be described below as an example. The multiple metal bodies 20 are arranged at a predetermined distance apart in the circumferential direction of the tube 10. In other words, two adjacent metal bodies 20 are separated by a predetermined distance around the axis x. The multiple metal bodies 20 are arranged, for example, at equal or approximately equal angular intervals in the circumferential direction along the cylindrical surface whose central axis is the axis x. The multiple metal bodies 20 have a curved shape. The multiple metal bodies 20 have two end portions and a portion (middle portion) between the two end portions in the circumferential direction. In the radial direction, the distance A between the end of the metal body 20 and the outer surface 12 of the tube 10 of the rotor 2 described later is larger than the distance B between the middle part of the metal body 20 and the outer surface 12 of the tube 10 of the rotor 2, and the end of the metal body 20 is farther away from the outer surface 12 of the tube 10 of the rotor 2 than the middle part.

[0010] As shown in FIGS. 1 to 4 , the cylinder 10 of the rotor 2 is a cylindrical member extending along the axis x. The cylinder 10 of the rotor 2 is attached to a rotating member of an external device to which the angle sensor 1 is applied, so that the axis x coincides or substantially coincides with the rotation axis of the rotating member of the external device. For example, as shown in FIGS. 1 to 4 , the cylinder 10 of the rotor 2 has an inner circumferential surface 11, which is a cylindrical surface extending along a cylindrical surface with the axis x as its central axis, and an outer circumferential surface 12, which is a cylindrical surface facing away from the inner circumferential surface 11 on the radially outer side (hereinafter also referred to as the "outer peripheral side"). The radial direction is a direction perpendicular to the axis x. The cylinder 10 also has two end faces 13 and 14, which are surfaces facing in the respective directions in which the axis x extends. These two end faces 13 and 14 form part of two end portions in the respective directions in which the axis x extends. The inner circumferential surface 11 and the outer circumferential surface 12 extend between an end surface 13 and an end surface 14. The angle sensor 1 is applied to, for example, a motor, in which the motor shaft is passed through the inner circumferential surface 11 of the cylinder 10 of the rotor 2, and the rotor 2 is fixed to the shaft.

[0011] The tube 10 is made of, for example, a resin material, a non-magnetic material, or a non-conductive material. The resin material of the tube 10 is, for example, an epoxy-based resin (thermosetting resin). However, the material of the tube 10 may be other resins. For example, the material of the tube 10 may be a recyclable resin. Furthermore, the non-magnetic material may be non-conductive. As described above, multiple metal bodies 20 are provided within the tube 10. The metal bodies 20 are made of a conductive metal material. For example, the metal bodies 20 are formed by press processing. For example, the tube 10 is formed integrally with the metal bodies 20 and resin by insert molding. The method of providing the metal bodies 20 within the tube 10 is not limited to insert molding. For example, the metal bodies 20 may be provided within the tube 10 by providing a recess shaped to correspond to the shape of the metal body 20 in the tube 10, accommodating the metal body 20 in the recess, and fixing the metal body 20 within the tube 10. In this case, the metal body 20 is fixed to the tube 10 by a known method such as press-fitting or adhesive bonding. The shape of the metal body 20 will be described later. Furthermore, the multiple metal bodies 20 may be connected to each other. The multiple metal bodies 20 are connected by one or more connecting parts, and the one or more connecting parts may be formed of a non-conductive material (e.g., resin) or a conductive material (e.g., metal), and the multiple metal bodies 20 may be electrically connected.

[0012] The coil 40 is made of a conductive material. The multiple coils 40 are, for example, lined up and connected in a circumferential direction around the axis x. As schematically shown in FIG. 1 , the multiple coils 40 form a cylindrical shape (hereinafter referred to as a coil structure) 4 extending annularly around the axis x. The coil structure 4 is a shape formed by arranging the multiple coils 40. In the coil structure 4, the multiple coils 40 are, for example, lined up annularly so as to be aligned along an annular surface around the axis x. The multiple coils 40 are, for example, lined up annularly so as to be aligned along a cylindrical surface with the axis x as the central axis. Furthermore, each coil 40 has, for example, a shape that surrounds a space. Furthermore, each coil 40 has, for example, a shape that the space surrounded by each coil 40 follows an annular surface around the axis x.

[0013] FIG. 5 is a perspective view of the stator 3, and FIG. 6 is a perspective view of a coil structure 4 formed by a plurality of coils 40. FIG. 7 is a diagram schematically illustrating the configuration of the coil structure 4. As shown in FIGS. 1 to 5 , the stator 3 has a cylindrical portion 31 that is a cylindrical part corresponding to the cylinder 10 of the rotor 2. The cylindrical portion 31 forms a space capable of accommodating the rotor 2 therein and has an inner circumferential surface 31a that defines this space. The inner circumferential surface 31a is a cylindrical surface extending along the axis x and facing the outer circumferential surface 12 of the cylinder 10 of the rotor 2 with an annular gap therebetween. The inner circumferential surface 31a is, for example, a cylindrical surface extending along a cylindrical surface with the axis x as its central axis.

[0014] As shown in FIGS. 2 to 5 , the stator 3 has an attachment portion 32 that is attached to an external device as an application target. As shown in FIGS. 3 and 5 , the attachment portion 32 is provided, for example, on the outer peripheral surface 31b of the cylindrical portion 31 and protrudes outward from the cylindrical portion 31. The outer peripheral surface 31b of the cylindrical portion 31 is a cylindrical surface facing away from the inner peripheral surface 31a. The attachment portion 32 also has a through hole 32a through which a fixing member such as a bolt is passed, allowing the attachment portion 32 to be attached to an external device via the fixing member. The stator 3 has, for example, three attachment portions 32. However, the number of attachment portions 32 of the stator 3 is not limited thereto. As shown in FIG. 5 , the stator 3 also has a holding portion 33 that houses, for example, an electric circuit device having a circuit unit (not shown), such as an IC, and a computing unit. 3 and 5, the holding portion 33 extends from the outer peripheral surface 31b of the cylindrical portion 31 along the axis x in one direction in the axis x direction. The holding portion 33 is also provided between the multiple mounting portions 32 in the circumferential direction.

[0015] As described above, the stator 3 has a plurality of protrusions 30 protruding toward the rotor 2. The protrusions 30 are portions that protrude from the inner circumferential surface 31a of the cylindrical portion 31 toward the inner circumferential side (inward in the radial direction r), as shown in FIG. 5 , for example. The protrusions 30 are provided on the inner circumferential surface 31a, for example, at equal or approximately equal angular intervals around the axis x. The protrusions 30 protrude from the inner circumferential surface 31a in the radial direction r, and have, for example, a rectangular or approximately rectangular cross section perpendicular to the radial direction r. The cross-sectional shape of the protrusions 30 is not limited to a rectangular shape and may be other shapes. Each protrusion 30 has a surface 30a facing the inner circumferential side, and the surface 30a faces the outer circumferential surface 12 of the cylinder 10 of the rotor 2 with an annular gap therebetween. The surfaces 30a of the plurality of protrusions 30 are, for example, arranged along a cylindrical surface whose central axis is the axis x. 8 , the protruding portion 30 includes, for example, a connecting portion 30b that connects to the cylindrical portion 31 and an end portion 30c on the rotor 2 side. A surface 30a is formed on the end portion 30c. The end portion 30c protrudes further in the circumferential direction and the direction of the axis x than the connecting portion 30b, and an annular groove is formed between the connecting portion 30b and the cylindrical portion 31.

[0016] The coil 40 is formed by, for example, winding a magnet wire as a conductive member. The coil 40 is formed by winding the magnet wire around a plurality of protrusions 30, as shown in Figures 5 and 6, for example. The coil 40 has an annular shape wound around the radial direction r of the cylinder 10, and surrounds a planar space facing the radial direction. A plurality of coils 40 are formed in the cylinder portion 31 of the stator 3, lined up around the axis x, to form the coil structure 4.

[0017] As shown in Figures 6 and 7, the coil structure 4 has two pieces (hereinafter referred to as coil structure pieces) 4a and 4b. The coil structure piece 4a is formed by multiple coils 40a, which are the coil 40 described above, connected in series in an annular shape. Similarly, the coil structure piece 4b is formed by multiple coils 40b, which are the coil 40 described above, connected in series in an annular shape. That is, multiple annular coils 40a or 40b are arranged in the circumferential direction. The coil structure piece 4a and the coil structure piece 4b are formed of conductive materials. The coil structure piece 4a and the coil structure piece 4b are coated with, for example, an insulating material (an insulating film or coating) and are electrically insulated from each other. As shown in Figure 6, the coil structure piece 4a and the coil structure piece 4b overlap each other in the radial direction to form the coil structure 4. In the coil structure pieces 4a and 4b, a portion of the space surrounded by the coil 40a is offset in the circumferential direction from a portion of the space surrounded by the coil 40b, and another portion of the space surrounded by the coil 40a is overlapped in the circumferential direction. Specifically, the space surrounded by the coil 40a is offset in the circumferential direction from the space surrounded by the coil 40b by half the width of the space surrounded by the coil 40a. The number of coils 40a and 40b in each of the coil structure pieces 4a and 4b corresponds to the axial multiplier angle set for the angle sensor 1. The number of coil structure pieces 4a and 4b corresponds to the number of detection signals output by the coil structure 4. Each coil 40a in the coil structure piece 4a has a length L1, and each coil 40b in the coil structure piece 4b has a length L2.

[0018] 5 to 7 , a magnet wire serving as a conductive member is wound around each of the protrusions 30 in the radial direction r, and a plurality of annular coils 40 are formed around the plurality of protrusions 30 in the radial direction r, thereby forming the coil structure 4 in the stator 3. For example, the coil structure pieces 4a, 4b are each formed by winding one magnet wire around the plurality of protrusions 30 of the cylindrical portion 31. Specifically, for example, for each of two adjacent protrusions 30, the magnet wire is wound around the protrusions 30 alternately from one side in the axial x direction and the other side in the axial x direction toward one side in the circumferential direction, and then turned back after going around the cylindrical portion 31, and the magnet wire is wound around the protrusions 30 again in the same manner toward the other side in the circumferential direction, thereby forming the coil structure pieces 4a, 4b. In this case, each of the coils 40a, 40b is formed around two of the protrusions 30. Furthermore, the coil structure pieces 4a and 4b are offset from each other by one protrusion 30 in the circumferential direction. Note that each of the coils 40a, 40b is not limited to being formed around two protrusions 30, but may be formed around other numbers of protrusions 30. While the magnet wire has been described as being wound around one circumference, the winding pattern of the magnet wire is not limited to this and may be wound around two or more circumferences. In other words, the coil 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 or axial direction. In this case, the output signal or the signal to be detected (e.g., the amplitude of the signal waveform) can be amplified compared to the case of one circumference or one layer.

[0019] As shown in Figures 5 to 7, each coil 40 (40a, 40b) formed by being wound around the multiple protrusions 30 of the tubular portion 31 extends linearly. That is, the portion of each coil 30 extending along each protrusion 30 on one side in the axial x direction and the other side in the axial x direction extends linearly. Furthermore, between two adjacent protrusions 30, the portions of the coil structure pieces 4a, 4b that intersect and extend between one side in the axial x direction and the other side in the axial x direction extend linearly. In particular, in order to prevent the coil 40 from coming off the multiple protrusions 30, the portions of the coil structure pieces 4a, 4b that intersect between two adjacent protrusions 30 are wound so as to have a large tension, making them linear.

[0020] The stator 3 is, for example, integrally molded from the same material, and each component of the stator 3 is connected together. The stator 3 is an insulating member, for example, a resin member. The stator is made of, for example, a resin material, a non-magnetic material, or a non-conductive material. The non-magnetic material may be non-conductive. Any or all of the components of the stator 3 may be formed as separate bodies. In this case, the stator 3 is formed by assembling the components formed as separate bodies by bonding or the like.

[0021] As described above, FIGS. 2 to 4 show the angle sensor 1 in use. The multiple metal bodies 20 and the multiple coils 40 face each other in the radial direction with an annular gap between them. As shown in FIGS. 1 and 4, the width W1 of the metal body 20 is, for example, wider than the width W2 of the coil 40. Note that the width W1 is the distance of the metal body 20 in the axial x direction, and the width W2 is the distance of the coil 40 in the axial x direction. This allows the entire width of the coil 40 in the axial x direction to face the metal body 20 in the radial direction (see FIGS. 1, 2, and 4). The metal body 20 also protrudes beyond the coil 40 in both directions along the axial x direction (see FIGS. 1, 2, and 4).

[0022] The rotor 2 and the stator 3 form an inductive angle sensor, and the multiple coils 40 form detection coils. A magnetic space or magnetic gap is formed between the rotor 2 and the stator 3. For example, in the angle sensor 1, a radially directed magnetic flux whose magnitude periodically changes acts on the multiple coils 40. Specifically, the stator 3 is provided with an excitation circuit 3a, which is a magnetic circuit that generates a periodically changing magnetic flux acting on each of the multiple coils 40. Meanwhile, the multiple metal bodies 20 are arranged in the circumferential direction around the axis x as described above, and cross the magnetic flux generated by the excitation circuit 3a as the rotor 2 rotates. Furthermore, the projection of the metal body 20, which has a portion extending along the axis x, onto the coils 40 in the radial direction moves as the rotor 2 rotates. For this reason, the magnetic fluxes from the excitation circuit 3a acting on each of the plurality of coils 40 are affected by eddy currents generated in the metal body 20 and cancel each other out, thereby changing periodically with the rotation of the rotor 2. As a result, electromotive forces that change with the rotation of the rotor 2 are generated in the plurality of coils 40 due to electromagnetic induction, and signals that change with the rotation of the rotor 2 are detected from the plurality of coils 40. Based on the detection signals from the plurality of coils 40, the rotation angle of the rotor 2 is detected in the electric circuit device.

[0023] Next, the metal body 20 will be described in detail. FIG. 8 is a partially enlarged view showing the portion surrounded by the frame line Z in FIG. 3 . Note that the coil 40 is not shown in FIG. 8 . As shown in FIGS. 1 , 3 , and 8 , the metal body 20 is a plate-like member and has a curved shape. The curved shape of the metal body 20 extends, for example, in a direction along the outer peripheral surface 12 of the tube 10. Furthermore, the curved shape of the metal body 20 is curved, for example, relative to the outer peripheral surface 12 of the tube 10. In other words, the curved shape of the metal body 20 extends, for example, in a direction along the inner peripheral surface 31 a or outer peripheral surface 31 b of the tube portion 31 of the stator 3 that faces the outer peripheral surface 12 of the tube 10, and is also curved, for example, relative to the inner peripheral surface 31 a or outer peripheral surface 31 b of the tube portion 31 of the stator 3.

[0024] Specifically, the radius of curvature of the metal body 20 is different from the radius of curvature of the outer peripheral surface 12 of the tube 10. In other words, the radius of curvature of the metal body 20 is different from the radius of curvature of the inner peripheral surface 31 a of the tube portion 31 of the stator 3. For example, the radius of curvature of the metal body 20 is smaller than the radius of curvature of the outer peripheral surface 12 of the tube 10. In other words, the radius of curvature of the metal body 20 is smaller than the radius of curvature of the inner peripheral surface 31 a or the outer peripheral surface 31 b of the tube portion 31 of the stator 3.

[0025] Specifically, as shown in FIGS. 1, 3, and 8, the metal body 20 has a pair of back-to-back surfaces, an outer surface 21 and an inner surface 22, and end surfaces 23 to 26 extending between the edge of the outer surface 21 and the edge of the inner surface 22. Thus, the metal body 20 is plate-shaped. Furthermore, the metal body 20 has a rectangular or substantially rectangular shape when viewed from the radial direction. As shown in FIG. 1, the end surfaces 23 and 24 are back-to-back, and the end surfaces 25 and 26 are back-to-back. As shown in FIGS. 1, 3, and 8, the metal body 20 is curved along the end surfaces 23 and 24. That is, the outer surface 21 is curved along the end surfaces 23 and 24, and the inner surface 22 is curved along the end surfaces 23 and 24. The outer surface 21 is curved so as to protrude in the direction in which the outer surface 21 faces. The inner surface 22 extends parallel or approximately parallel to the outer surface 21. Therefore, the end surfaces 23, 24 extend in a curved manner so as to protrude in the direction facing the outer surface 21. Furthermore, the end surfaces 23, 24 extend, for example, on a plane or approximately on a plane.

[0026] 1, 3, and 8, the metal body 20 extends, for example, uniformly or approximately uniformly along the end faces 25, 26. That is, the end faces 25, 26 extend on a plane or approximately on a plane, and extend parallel or approximately parallel to the extension direction of the metal body 20, which is the direction from one of the end faces 23 and 24 to the other. The shape of the cross section of the metal body 20 perpendicular to the extension direction is the same or approximately the same throughout the extension direction of the metal body 20.

[0027] FIG. 9 is a cross-sectional view of the metal body 20 in a plane perpendicular to the extension direction of the metal body 20 (the direction in which the metal body 20 extends) or the axial x direction of the rotor 10. As shown in FIG. 9 , in a cross section perpendicular to the extension direction, the outer surface 21 describes, for example, a circular arc or an approximately circular arc, and has a constant or approximately constant radius of curvature R1. Note that the outer surface 21 does not have to describe an arc in a cross section perpendicular to the extension direction. For example, the outer surface 21 may describe an arc, another curve, a line formed by combining multiple straight lines, or a line formed by combining one or more straight lines and one or more curves, etc. Specifically, for example, the outer surface 21 may describe a line having corners or a wavy line in a cross section perpendicular to the extension direction. Furthermore, the outer surface 21 does not have to form a line that is convex on the side opposite to the inner surface 22 in a cross section perpendicular to the extension direction, but may form a line that is convex on the side of the inner surface 22 in a cross section perpendicular to the extension direction. In other words, the outer surface 21 may be curved so as to protrude toward the inner surface 22, rather than being curved so as to protrude toward the side that the outer surface 21 faces.

[0028] As shown in FIGS. 1 , 3 , and 8 , each of the multiple metal bodies 20 is provided in the rotor 2 so that, for example, the extension direction of the metal body 20 is parallel or approximately parallel to the axis x. Furthermore, each of the multiple metal bodies 20 is provided in the rotor 2 so that, for example, the extension direction of the metal body 20 is symmetrical or approximately symmetrical with respect to a plane extending in the radial direction including the axis x. Furthermore, the multiple metal bodies 20 are arranged at the same or approximately the same radial position from the axis x, at equal or approximately equal angular intervals around the axis x. Furthermore, for example, each of the multiple metal bodies 20 has end faces 23 and 24 exposed at end faces 13 and 14 of the rotor 2, respectively. Each of the multiple metal bodies 20 may be entirely embedded in the rotor 2, or may be partially exposed to the outside of the rotor 2. Furthermore, each of the multiple metal bodies 20 may be provided in the rotor 2 so that the extension direction of the metal body 20 is inclined with respect to the axis x.

[0029] Each of the multiple metal bodies 20 has a length L3 in the circumferential direction. The length L3 of this metal body 20 is greater than the lengths L1 and L2 of the annular coils 40a and 40b. Furthermore, the length L3 of this metal body 20 is equal to or less than the lengths L1 and L2 of the annular coils 40a and 40b. In the circumferential direction, the distance between both end faces 25 and 26 of the metal body 20 is greater than the distance between both end portions of the annular coils 40a and 40b. Furthermore, in the direction of the axis x, the lengths of both end faces 25 and 26 of the metal body 20 are equal to or greater than the lengths of both end portions of the annular coils 40a and 40b. However, without being limited thereto, the length L3 of the metal body 20 may be adjusted to be less than the sum of the lengths L1 and L2 of the annular coils 40a and 40b, or the lengths of both end portions of the metal body 20 may be adjusted to be less than the lengths of both end portions of the annular coils 40a and 40b.

[0030] FIG. 10 is a cross-sectional view showing a cross section perpendicular to the axis x of the angle sensor 1 in the use state shown in FIGS. 2 to 4 , and is a partially enlarged cross-sectional view showing the cross section of the portion indicated by the frame line A in FIG. 3 . In FIG. 10 , the radial line r0 is a radial line passing through the circumferential center of the outer surface 21, and the radial lines r1 and r2 are radial lines passing through both edges of the outer surface 21 (the edges connecting to the end faces 25 and 26). As described above, the metal body 20 is provided on the rotor 2 so as to be symmetrical or approximately symmetrical with respect to a plane extending in the radial direction and including the axis x. As shown in FIG. 10 , both edges of the outer surface 21 are located at the same or approximately the same distance from the axis x. Note that the two-dot chain line shown in FIG. 10 represents a virtual inner circumferential surface 31a obtained by extending the inner circumferential surface 31a of the stator 3.

[0031] As shown in Fig. 10 , in cross section, the shape of the outer surface 21 of the metal body 20 is different from the shape of the inner circumferential surface 31a of the tubular portion 31 of the stator 3. For example, as shown in Fig. 10 , the radius of curvature of the inner circumferential surface 31a of the stator 3 is radius of curvature R2, which is larger than radius of curvature R1 of the outer surface 21 of the metal body 20. Also, as shown in Fig. 10 , the distance between the outer surface 21 of the metal body 20 and the inner circumferential surface 31a of the stator 3 along a radial line r0 passing through the circumferential center of the outer surface 21 is distance D0. Also, as shown in Fig. 10 , the distances between the outer surface 21 of the metal body 20 and the inner circumferential surface 31a of the stator 3 along radial lines r1 and r2 passing through both edges of the outer surface 21 are distances D1 and D2, respectively. Distance D0 is smaller than distances D1 and D2, and distances D1 and D2 are the same or approximately the same.

[0032] As described above, the radial distance between the outer surface 21 of the metal body 20 and the inner circumferential surface 31 a of the stator 3 is smallest (distance D0) at the center of the outer surface 21 and increases toward both edges of the outer surface 21. As described above, the coil 40 is wound around the connecting portions 30 b of the multiple protrusions 30 so as to follow the inner circumferential surface 31 a of the cylindrical portion 31 of the stator 3. Note that, because the coil 40 is wound around the multiple protrusions 30 so as to generate tension, the coil 40 is located on the end 30 c side of the protrusion 30. Therefore, the radial distance between the outer surface 21 of the metal body 20 and the coil 40 or the space surrounded by the coil 40 is smallest at the center of the outer surface 21 and increases toward both edges of the outer surface 21. Therefore, the effect of eddy currents generated in the metal body 20 rotating with the rotation of the rotor 2 on the magnetic flux from the excitation circuit 3 a acting on each coil 40 varies in the circumferential direction of the metal body 20.

[0033] The metal body 20 may be curved along the outer peripheral surface 12 of the cylinder 10 of the rotor 2, that is, it may be curved along the inner peripheral surface 31 a or the outer peripheral surface 31 b of the stator 3. Specifically, the radius of curvature R1 of the outer peripheral surface 21 of the metal body 20 and the radii of curvature R2, R3 of the inner peripheral surface 31 a and the outer peripheral surface 31 b of the stator 3 may be the same or approximately the same. In this case, the radial distance between the outer surface 21 of the metal body 20 and the inner peripheral surface 31 a and the outer peripheral surface 31 b of the stator 3 is uniform or approximately uniform over the entire circumferential width of the outer surface 21.

[0034] The angle sensor 1 has the above-described configuration, and each metal body 20 faces in the radial direction. Therefore, the metal bodies 20 can suppress the influence of movement of the rotor 2 in the axial x direction. For example, the rigidity of the metal bodies 20 against vibration of the rotor 2 in the axial x direction is increased, which increases the accuracy of the angle sensor 1 and also increases the strength of the metal bodies 20 against vibration of the rotor 2 in the axial x direction. Furthermore, the metal bodies 20 are embedded in the cylinder 10 of the rotor 2, which also increases the strength of the metal bodies 20 against vibration of the rotor 2 in the axial x direction.

[0035] Furthermore, the cylinder 10 of the rotor 2 is cylindrical and extends along the axis x, and even if the radial thickness is reduced, the strength of the cylinder 10 against vibration in the direction of the axis x of the rotor 2 can be maintained at a high level. This allows the radial thickness of the cylinder 10 to be reduced, making the rotor 2 lighter and reducing the installation space for the rotor 2. Furthermore, for example, the cylinder 10 of the rotor 2 can be insert-molded together with the metal bodies 20, making it easy to install multiple metal bodies 20 on the rotor 2.

[0036] As described above, the coil structure 4 has a cylindrical shape extending along the axis x, and each coil 40 is aligned along the axis x and faces in the radial direction. This allows the coils 40 to suppress the effects of movement of the stator 3 in the direction of the axis x. For example, the rigidity of the coils 40 against vibration of the stator 3 in the direction of the axis x is increased, thereby improving the accuracy of the angle sensor 1 and increasing the strength of the coils 40 against vibration of the stator 3 in the direction of the axis x. Furthermore, the coils 40 can be formed of magnet wire, eliminating the need for connections between the coils 40.

[0037] Furthermore, by making the width W1 of the metal body 20 in the axial x direction larger than the width W2 of the coil 40 in the axial x direction, the metal body 20 can be extended beyond the coil 40 in both directions along the axial x. As a result, even if relative movement occurs between the rotor 2 and the stator 3 in the axial x direction and the positional relationship between the rotor 2 and the stator 3 in the axial x direction deviates from the desired positional relationship, the entire width W2 of the coil 40 can face the metal body 20. Therefore, even if the positional relationship between the rotor 2 and the stator 3 in the axial x direction deviates from the desired positional relationship, the accuracy of the detected angle is not affected or the effect on the accuracy of the detected angle can be reduced. Furthermore, even if eccentricity occurs between the rotor 2 and the stator 3, the widening and narrowing portions of the radial spacing between the multiple metal bodies 20 and the coil structure 4 are balanced, so even in this case, the accuracy of the detected angle is not affected or the effect on the accuracy of the detected angle can be reduced.

[0038] Furthermore, by embedding the metal body 20 in a resin member, the durability of the metal body 20 against oil, heat, and dust can be improved.

[0039] As described above, each coil 40 (40a, 40b) wound around the multiple protrusions 30 of the cylindrical portion 31 extends linearly. In particular, to prevent the coils 40 from coming off the multiple protrusions 30, the portions of the coil structure pieces 4a, 4b that intersect between two adjacent protrusions 30 are wound with high tension and linearly (see FIGS. 5 to 7). Meanwhile, as described above, the metal body 20 is curved, and the radial distance between the outer surface 21 of the metal body 20 and the coil 40 or the space surrounded by the coil 40 is smallest at the center of the outer surface 21 and increases toward both edges of the outer surface 21 (see FIG. 10). As a result, the influence of eddy currents generated in the metal body 20 rotating with the rotation of the rotor 2 on the magnetic flux from the excitation circuit 3a acting on each coil 40 varies circumferentially around the metal body 20.

[0040] Therefore, the output waveform obtained from the detection signal detected by the coil structure 4 can be made closer to a sine wave, and the output waveform can be prevented from becoming a waveform close to a triangular wave, thereby improving the accuracy of the angle sensor 1.

[0041] On the other hand, when the radial distance between the outer surface 21 of the metal body 20 and the coil 40 or the space surrounded by the coil 40 is uniform across the entire circumferential width of the outer surface 21, for example, when the radius of curvature R1 of the outer surface 21 of the metal body 20 is the same as the radius of curvature R2 of the inner surface 31a and outer surface 31b of the tubular portion 31 of the stator 3, the output waveform obtained from the detection signal detected from the coil structure 4 will be a waveform close to a triangular wave.

[0042] Next, a modified example of the rotor 2 will be described. FIG. 11 is a front view of a rotor 5 according to a modified example. Hereinafter, regarding the configuration of the rotor 5, components that are the same as or have similar functions to those of the rotor 2 described above will be denoted by the same reference numerals and will not be described again, and only components that differ from the rotor 2 will be described. As shown in FIG. 11 , the rotor 5 has a tube 16 that is different from the tube 10 of the rotor 2. The tube 16 has an outer circumferential surface 17 that is different from the outer circumferential surface 12 of the tube 10. The outer circumferential surface 17 of the tube 16 has protruding surfaces 17a that form portions that protrude outward in correspondence with the multiple metal bodies 20. The protruding surfaces 17a are formed in the same number as the number of metal bodies 20. As shown in FIG. 11 , the protruding surfaces 17a have a shape that follows the outer surfaces 21 of the metal bodies 20.

[0043] Next, another modification of the rotor 2 will be described. FIG. 12 is a front view of a rotor 6 according to another modification. Hereinafter, regarding the configuration of the rotor 6, components that are the same as or have similar functions to those of the rotor 2 described above will be denoted by the same reference numerals and will not be described again, and only components that differ from the rotor 2 will be described. As shown in FIG. 12 , the rotor 6 has a tube 18 that is different from the tube 10 of the rotor 2. In the tube 18, the outer peripheral surface 17 extends a predetermined distance in the axial x direction from the end face 14 and extends to a portion (intermediate portion) between the end face 14 and the end face 13. As shown in FIG. 12 , an outer peripheral surface 19 is formed between the outer peripheral surface 17 and the end face 13 in the axial x direction. The outer peripheral surface 19 is formed with mounting surfaces 19 a, which correspond to the inner surfaces 22 of the metal bodies 20, and the number of the mounting surfaces 19 a is the same as the number of the metal bodies 20. The multiple mounting surfaces 19 a are provided at predetermined positions, for example, at the same or approximately the same radial positions, at equal or approximately equal angular intervals. The mounting surface 19 a has, for example, the same or substantially the same shape as the inner surface 22 of the metal body 20 .

[0044] 12, a surface 19b (hereinafter referred to as a protruding surface) protruding outward from the mounting surface 19a is formed between the two adjacent mounting surfaces 19a. The protruding surface 19b is located on the inner peripheral side of the outer peripheral surface 12. The protruding surface 19b may be located on the outer peripheral side of the outer peripheral surface 12, or may be flush with the outer peripheral surface 12.

[0045] In the rotor 6, the multiple metal bodies 20 are fixed to the multiple mounting surfaces 19a, respectively. That is, the inner surface 22 of each metal body 20 is in contact with the corresponding mounting surface 19a, and the inner surface 22 is fixed to the mounting surface 19a. For example, the inner surface 22 is adhesively bonded to the mounting surface 19a. The method of fixing the metal body 20 to the mounting surface 19a is not limited to adhesive. For example, the metal body 20 may be press-fitted between two adjacent protruding surfaces 19b and fixed thereto. Furthermore, for example, the metal body 20 may be press-fitted between two adjacent protruding surfaces 19b, and the inner surface 22 may be adhesively bonded to the mounting surface 19a, and the metal body 20 may be fixed to the mounting surface 19a.

[0046] 13, the rotor 6 may have a cylindrical cover 18a that covers the metal body 20. The cover 18a is fixed to the outer circumferential surface 19. For example, the cover 18a is configured so that an inner circumferential surface 18b of the cover 18a contacts the protruding surface 19b, and an outer circumferential surface 18c of the cover 18a is flush or approximately flush with the outer circumferential surface 12. The cover 18a is made of the same material as the cylinder 18, for example.

[0047] Next, an application of the angle sensor 1 will be described. Fig. 14 is an exploded perspective view of a specific example of a rotating device as an application of the angle sensor 1. Fig. 14 shows a rotating device 50 as a specific example of a rotating device in an exploded state. In Fig. 14, a part of the configuration of the rotating device 50 is shown in a see-through manner.

[0048] As shown in FIG. 14 , the rotating device 50 includes an angle sensor 1, a rotating shaft 51, and a motor 52. In the rotating device 50, the axes of the rotating shaft 51 and the motor 52 coincide or substantially coincide with the axis x of the angle sensor 1. For this reason, in the following description, the axis of the rotating device 50 is referred to as the axis x, and the axes of the angle sensor 1, the rotating shaft 51, and the motor 52 are referred to as the axis x. The motor 52 includes a rotor 53 and a stator 54, and the rotating shaft 51 is fixed to the rotor 53. The motor 52 also includes a frame 55 and a cover 60. The frame 55 houses the rotor 53 and the stator 54. The frame 55 also has an opening 55 a. The cover 60 covers the opening 55 a of the frame 55.

[0049] An opening 55a of the frame 55 opens the internal space of the frame 55 to the outside of the frame 55. The internal space of the frame 55 houses the rotor 53 and the stator 54. As shown in Fig. 14, the frame 55 is, for example, a cylindrical member. The frame 55 has an annular end portion 55b surrounding the opening 55a, and the end portion 55b faces in the direction of the axis x.

[0050] The rotor 2 of the angle sensor 1 is fixed to a rotating shaft 51, and one end 51a of the rotating shaft 51 (hereinafter referred to as the tip) passes through the rotor 2 and is rotatably supported by a bearing 56 fixed to a cover 60. The stator 3 of the angle sensor 1 is fixed to the cover 60. In the rotating device 50, as described above, the rotor 2 is located at a predetermined position relative to the stator 3, and the outer circumferential surface 12 of the rotor 2 faces the protruding portion 30 and the coil structure 4 of the stator 3 with an annular gap therebetween (see FIGS. 2 and 3 ).

[0051] The cover 60 is a plate-shaped member having a pair of opposing surfaces 61 and 62, as shown in FIG. 14 , for example. In the rotating device 50, one of the pair of opposing surfaces 61 and 62 of the cover 60, for example, the surface 61, covers the opening 55a of the frame 55. That is, the cover 60 is fixed to the frame 55 with the surface 61 in contact with the end 55b of the frame 55. For example, the surface 61 of the cover 60 is adhered to the end 55b of the frame 55, thereby fixing the cover 60 to the frame 55. Fixing the cover 60 to the frame 55 may be done by a method other than adhesion. For example, the cover 60 may be fixed to the frame 55 by a fixing means such as a bolt or a locking means such as a claw.

[0052] The angle sensor 1 is attached to a surface 61, which is one of a pair of surfaces of the cover 60. For example, the surface 61 of the cover 60 is provided with a plurality of mounting portions (hereinafter referred to as boss portions) 63 corresponding to the plurality of mounting portions 32 of the stator 3. As shown in FIG. 14 , the boss portions 63 are portions that protrude from the surface 61 and have threaded holes. Bolts 65 are threaded into the threaded holes of the bosses 63 via the mounting portions 32 of the stator 3, and the mounting portions 32 are fixed to the corresponding boss portions 63 by the bolts 65, thereby fixing the stator 3 to the cover 60. In this way, the stator 3 is fixed to the surface 61 of the cover 60, and the angle sensor 1 is provided on the surface 61 of the cover 60. Therefore, in the rotating device 50, the angle sensor 1 is housed in the space inside the frame 55.

[0053] 14 , for example, an annular protrusion 64 that supports the bearing 56 is formed on the surface 61 of the cover 60. The protrusion 64 is an annular tube that protrudes from the surface 61 of the cover 60 and has a recess formed therein. The protrusion 64 is a flange that extends a predetermined distance in the radial direction. The protrusion 64 houses the bearing 56, and the bearing 56 is fitted and fixed in place. For example, the bearing 56 is press-fitted into the recess formed by the protrusion 64, and the bearing 56 is fixed to the protrusion 64. In this way, the bearing 56, which rotatably supports the tip end 51 a of the rotary shaft 51 attached to the motor 52, is supported by the cover 60.

[0054] The rotating device 50 has the above-described configuration, and when the motor 52 is driven and the rotating shaft 51 rotates, the rotor 2 of the angle sensor 1 fixed to the rotating shaft 51 rotates around the axis x together with the rotating shaft 51. As a result, the metal body 20 of the rotor 2 rotates facing the coils 40 (40a, 40b) formed by the coil structure 4 of the stator 3 of the angle sensor 1, and the magnetic flux from the excitation circuit 3a acting on each of the multiple coils 40 changes periodically. As a result, signals that change as the rotor 2 rotates are detected from the multiple coils 40. Based on the detection signals from the multiple coils 40, the rotation angle of the rotor 2 is detected in an electric circuit device, which is an external device connected to the angle sensor 1.

[0055] Next, a modified example of the cover 60 provided in the rotating device 50 described above will be described. Fig. 15 is an exploded perspective view of the rotating device 50 provided with a cover 66 according to the modified example. The cover 66 differs from the cover 60 described above in that the position at which the angle sensor 1 is provided is different. Hereinafter, regarding the configuration of the cover 66, the same configurations as those of the cover 60 described above or configurations having similar functions will be assigned the same reference numerals and description thereof will be omitted, and configurations different from the cover 60 will be described.

[0056] As shown in FIG. 15 , the angle sensor 1 is provided on the surface 62 of the cover 66, which is the other of the pair of surfaces of the cover 66. Bosses 63 serving as a plurality of mounting portions corresponding to the plurality of mounting portions 32 of the stator 3 are provided on the surface 62 of the cover 66. Furthermore, instead of the protrusions 64 of the cover 60, holes (hereinafter referred to as through holes 67) penetrating between the surfaces 61 and 62 are formed on the cover 66, and the bearings 56 are supported in the through holes 67. For example, the bearings 56 are housed and press-fitted into the through holes 67, and the bearings 56 are fixed in the through holes 67. In this way, the bearings 56 that rotatably support the rotating shaft 51 attached to the motor 52 are supported by the cover 66.

[0057] The stator 3 is fixed to the cover 66 in the same manner as the fixation to the cover 60 described above. The rotor 2 of the angle sensor 1 is fixed to the tip 51a of the rotating shaft 51 protruding from the surface 62 of the cover 66 through a bearing 56 fixed in a through-hole 67 of the cover 66. As described above, the rotor 2 is located at a predetermined position relative to the stator 3, and the outer circumferential surface 12 of the rotor 2 faces the protruding portion 30 of the stator 3 and the coil structure 4 with an annular gap therebetween (see FIGS. 2 and 3 ). In this manner, the stator 3 is fixed to the surface 62 of the cover 66, and the angle sensor 1 is provided on the surface 62 of the cover 66. Therefore, in the rotating device 50 including the cover 66, the angle sensor 1 is not housed in the internal space of the frame 55 but is located outside the frame 55 and exposed to the outside of the rotating device 50, or the angle sensor 1 is covered by a cup-shaped protective cover. Covering the angle sensor 1 with a protective cover can provide waterproof and dustproof performance.

[0058] In the above structure, the angle sensor 1 is located outside the frame 55, so the diameter of the rotating shaft 51 can be made small without being affected by the structure of the motor 52, and therefore the diameter of the rotor 2 of the angle sensor 1 can be made small. As a result, the size of the angle sensor 1 itself can be made small.

[0059] Next, a fixing configuration between the rotating shaft 51 and the rotor 2 of the angle sensor 1 in the rotating device 50 will be described. Fig. 16 is a perspective view showing the tip 51a of the rotating shaft 51 and its vicinity, and Fig. 17 is a perspective view of a specific example of the rotor 2 of the angle sensor 1. As shown in Fig. 16, a recess 51b is formed on the outer circumferential surface of the tip 51a of the rotating shaft 51. Furthermore, as shown in Fig. 17, the rotor 2 is formed with a protrusion 15 that is received in the recess 51b of the rotating shaft 51.

[0060] 16 , a step is formed on the tip end 51a of the rotating shaft 51, and the rotating shaft 51 includes a first outer peripheral surface 51c, a second outer peripheral surface 51d, and a third outer peripheral surface 51e. The first outer peripheral surface 51c is the main outer peripheral surface of the rotating shaft 51 and is a cylindrical surface extending along the axis x from the tip end 51a to the other end of the rotating shaft 51. The second outer peripheral surface 51d and the third outer peripheral surface 51e are formed on the tip end 51a. The second outer peripheral surface 51d is a cylindrical surface extending along the axis x and is adjacent to the first outer peripheral surface 51c. The third outer peripheral surface 51e is a cylindrical surface extending along the axis x and is adjacent to the second outer peripheral surface 51d on the side opposite to the first outer peripheral surface 51c.

[0061] 16, the second outer peripheral surface 51d has a radial width smaller than that of the first outer peripheral surface 51c, and a stepped surface 51f, which is an annular surface, is formed between the first outer peripheral surface 51c and the second outer peripheral surface 51d. The third outer peripheral surface 51e has a radial width smaller than that of the second outer peripheral surface 51d, and a stepped surface 51g, which is an annular surface, is formed between the second outer peripheral surface 51d and the third outer peripheral surface 51e. The stepped surfaces 51f and 51g face in the direction of the axis x.

[0062] As shown in FIG. 16 , the recess 51b is formed in the second outer peripheral surface 51d, forming a groove recessed toward the inside of the rotating shaft 51 in the second outer peripheral surface 51b. The recess 51b extends along the axis x. The recess 51b extends to the step surface 51g and opens at the step surface 51g. The recess 51b does not extend to the step surface 51f. The inner peripheral surface 11 of the rotor 2 is fixed to the second outer peripheral surface 51d. For example, a portion of the second outer peripheral surface 51d of the rotating shaft 51 is press-fitted into a space surrounded by the inner peripheral surface 11 of the rotor 2, thereby fixing the inner peripheral surface 11 of the rotor 2 to the second outer peripheral surface 51d. The configuration for fixing the rotor 2 to the outer peripheral surface 51d of the rotating shaft 51 is not limited to the configuration in which the rotor 2 is fixed by press-fitting. For example, the second outer peripheral surface 51d of the rotating shaft 51 may be inserted into a space surrounded by the inner peripheral surface 11 of the rotor 2, and the inner peripheral surface 11 of the rotor 2 and the second outer peripheral surface 51 may be bonded together with an adhesive or the like to fix the inner peripheral surface 11 of the rotor 2 to the second outer peripheral surface 51. Alternatively, a separate member such as a metallic ring 57 may be press-fitted to sandwich and fix the rotor 2 between the stepped surface 51f of the rotating shaft 51 and the ring 57. If the ring 57 is metallic, it may be made of the same material as the rotating shaft 51. In this case, the linear expansion coefficient of the ring 57 is the same as that of the rotating shaft 51, thereby preventing the ring 57 from coming loose due to thermal deformation. Alternatively, the ring 57 may be made of a different material from that of the rotating shaft 51.

[0063] As described above, the recess 51b does not extend to the step surface 51f, which shortens the cutting time. In addition, the cutting area can be reduced, which prevents the strength of the rotating shaft 51 from decreasing.

[0064] 16, the first outer peripheral surface 51c and the third outer peripheral surface 51e at the position of the recess 51b in the circumferential direction are curved surfaces. The second outer peripheral surface 51d is, for example, a cylindrical or approximately cylindrical surface extending along the axis x, and the third outer peripheral surface 51e is, for example, a cylindrical or approximately cylindrical surface extending along the axis x.

[0065] 17 , the protrusion 15 is formed on the inner circumferential surface 11 of the rotor 2. The protrusion 15 is a portion that protrudes inward from the inner circumferential surface 11, and extends in the direction of the axis x, for example, as shown in FIG. 17 , from the end surface 13 to partway between the end surface 13 and the end surface 14. Note that the protrusion 15 may extend to the end surface 14.

[0066] As described above, since the rotor 2 is molded from a resin material, it is easy to mold the protrusions 15 so that they extend partway between the end face 13 and the end face 14, that is, to be small in the direction of the axis x. This allows the length of the recesses 51b that accommodate the protrusions 15 in the direction of the axis x to be small.

[0067] By inserting the tip end 51a of the rotating shaft 51 into the rotor 2 so that the protrusion 15 of the rotor 2 fits into the recess 51b of the rotating shaft 51, the circumferential position of the rotor 2 relative to the rotating shaft 51 is set to a predetermined position. In this way, in this specific example, the circumferential positioning of the rotor 2 relative to the rotating shaft 51 is facilitated when fixing the rotor 2 to the rotating shaft 51. When the rotor 2 is fixed to the rotating shaft 51, the end face 14 of the rotor 2 is in contact with the stepped surface 51f of the rotating shaft 51. When the rotor 2 is fixed to the rotating shaft 51, the end face 14 of the rotor 2 does not have to be in contact with the stepped surface 51f of the rotating shaft 51.

[0068] In the above embodiment, the stator 3 includes the cylindrical portion 31, which is a cylindrical portion, and has a circumferentially continuous annular shape. However, the shape of the stator 3 is not limited to this. FIG. 18 is a perspective view showing a modified example of the stator 3. For example, as shown in FIG. 18, the stator 3 may be arc-shaped, or may extend only along a partial circumferential section of the entire circumference of the stator 3. The stator 3 according to the modified example is formed from the same material as the stator 3 described above. The stator 3 according to the modified example is formed, for example, from an insulating resin member. The stator 3 according to the modified example will be specifically described below. Note that, with regard to the configuration of the stator 3 according to the modified example, the same reference numerals will be used to designate components that have the same configuration or similar functions as the stator 3 described above, and their description will be omitted.

[0069] As shown in FIG. 18 , the stator 3 according to the modified example specifically has, for example, instead of the cylindrical tubular portion 31, a portion 31A extending in an arc-like or substantially arc-like shape (hereinafter referred to as the arc portion) corresponding to a circumferential section of the tubular portion 31. As shown in FIG. 18 , a plurality of protrusions 30 are formed in a row on the inner circumferential surface 31a of the arc portion 31A, similar to the stator 3 described above. The arc portion 31A has a plurality of protrusions 30 formed in a portion of the tubular portion 31 corresponding to the arc portion 31A. The stator 3 according to the modified example is provided with a detection coil and an excitation circuit. The detection coil is formed by a plurality of coils 40, similar to the detection coil (coil structure 4) provided in the stator 3 described above. Specifically, the plurality of coils 40 are arranged so as to form the coil structures 4a and 4b located in the portion of the tubular portion 31 corresponding to the arc portion 31A. In the stator 3 according to the modified example, similar to the plurality of coils 40 in the above-described stator 3, the plurality of coils 40 are formed by winding a conductive member such as a magnet wire around the protruding portion 30. Similar to the above-described excitation circuit 3a, the excitation circuit is a magnetic circuit that generates a periodically changing magnetic flux that acts on each of the plurality of coils 40 formed in the arc portion 31A.

[0070] Similar to the stator 3 described above, the stator 3 according to the modified example also has mounting portions 32, which are portions that are attached to an external device as an application target. In the stator 3 according to the modified example, the mounting portions 32 are provided, for example, at two circumferential ends of the arc portion 31A. Furthermore, the stator 3 according to the modified example has an electric circuit device mounted or fixed thereto, including a circuit unit (not shown), such as an IC, and a calculation unit. Specifically, for example, the stator 3 according to the modified example has a holding portion 33 that accommodates the electric circuit device, similar to the stator 3 described above. The electric circuit device may be provided on one of the circumferential ends of the stator. In this case, a large area can be secured for the excitation circuit and the detection coil, contributing to improved detection accuracy. Furthermore, the electric circuit device and the excitation circuit or the detection coil may be adjacent to each other in the circumferential direction. In other words, the electric circuit device is sandwiched between the detection coil or excitation circuit and the mounting portion 32 in the circumferential direction. In this case, the limited space in the stator 3 can be effectively utilized, contributing to the miniaturization of the angle sensor 1.

[0071] In addition, in the above-described stator 3 and the stator 3 according to the modified example, the stator 3 and the electric circuit device may be sealed with an insulating resin member or the like. In this case, the resin can protect the stator 3 and the electric circuit device from foreign matter and the like.

[0072] Furthermore, the stator 3 described above and the stator 3 according to the modified example may also include a connector that can be electrically connected to an external device. The connector may be provided adjacent to the electric circuit device. In this case, the electric circuit device and the connector can be connected via the shortest path, which contributes to miniaturization of the angle sensor 1.

[0073] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0074] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. Furthermore, the above-described embodiments do not limit the scope of the present invention, and the present invention may include any and all applications. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those illustrated and may be modified as appropriate. For example, the present invention includes differences that arise during implementation due to manufacturing tolerances, etc. Furthermore, components illustrated in different embodiments may be partially substituted or combined within the scope of technical inconsistency. Furthermore, the various configurations may be selectively combined as appropriate to achieve at least some of the above-described problems and effects.

[0075] 1 Angle sensor, 2, 5, 6 Rotor, 3 Stator, 3a Excitation circuit, 4 Coil structure, 4a, 4b Coil structure pieces, 10, 16, 18 Cylinder, 11 Inner peripheral surface, 12, 17, 19 Outer peripheral surface, 13, 14 End surface, 15 Convex portion, 17a Protruding surface, 18a Cover, 18b Inner peripheral surface, 18c Outer peripheral surface, 19a Mounting surface, 19b Protruding surface, 20 Metal body, 21 Outer surface, 22 Inner surface, 23, 24, 25, 26 End surface, 30 Protruding portion, 30a Surface, 30b Connecting portion, 30c End, 31 Cylinder portion, 31A Arc portion, 31a Inner peripheral surface, 31b Outer peripheral surface, 32 Mounting portion, 32a Through hole, 33 Holding portion, 40, 40a, 40b Coil, 50 Rotating device, 51 Rotating shaft, 51a Tip portion, 51b Recessed portion, 51c First outer peripheral surface, 51d Second outer peripheral surface, 51e Third outer peripheral surface, 51f, 51g Step surface, 52 Motor, 53 Rotor, 54 Stator, 55 Frame, 55a Opening, 55b End portion, 56 Bearing, 57 Press-fit ring, 60, 66 Cover, 61, 62 Surface, 63 portion Boss, 64 Protrusion, 65 Bolt, 67 Through hole, A, B, D0, D1, D2 Distance, R1, R2 Radius of curvature, r0, r1, r2 Radial line, x Axis line, W1, W2 Width

Claims

1. An angle sensor comprising: a rotor having a cylinder and a plurality of metal bodies fixed to the cylinder; and a stator having a plurality of protrusions protruding toward the rotor and a plurality of coils surrounding the plurality of protrusions, wherein the plurality of metal bodies are located inside the cylinder.

2. The angle sensor according to claim 1, wherein each of the plurality of metal bodies has a curved shape.

3. The angle sensor according to claim 2, wherein the curved shapes of the plurality of metal bodies extend in a direction along the inner circumferential surface of the cylinder.

4. The angle sensor according to claim 2, wherein the curved shapes of the plurality of metal bodies extend in a direction along the outer circumferential surface of the tube.

5. The angle sensor according to claim 2, wherein the curved shapes of the plurality of metal bodies are curved relative to the inner circumferential surface of the cylinder.

6. The angle sensor according to any one of claims 1 to 5, wherein the radius of curvature of the metal body is different from the radius of curvature of the inner peripheral surface of the cylinder.

7. The angle sensor according to claim 6, wherein the radius of curvature of the metal body is smaller than the radius of curvature of the inner peripheral surface of the cylinder.

8. The angle sensor according to any one of claims 1 to 7, wherein each of the plurality of metal bodies has a rectangular shape when viewed from a radial direction.

9. The angle sensor according to claim 1, wherein the plurality of metal bodies are arranged at predetermined distances in the circumferential direction of the cylinder.

10. An angle sensor as described in any one of claims 1 to 9, wherein the multiple coils are wound around the multiple protrusions, some of the multiple coils are connected around the rotor to form a coil structure, and other parts of the multiple coils are connected around the rotor to form another coil structure, the part of the multiple coils and the other parts of the multiple coils are offset from each other in the circumferential direction, and the part of the multiple coils and the other parts of the multiple coils overlap each other in the radial direction.

11. A rotating device comprising: an angle sensor according to any one of claims 1 to 10; a rotating shaft fixed to a rotor of the angle sensor; and a motor including a rotor fixed to the rotating shaft and a stator.

12. The rotating device according to claim 11, wherein the motor comprises: a frame that houses the rotor and the stator; and a cover that covers an opening of the frame, and the angle sensor is fixed to the cover.

13. The rotating device according to claim 12, wherein the cover has a pair of opposing surfaces, one of the pair of opposing surfaces covers the opening, and the angle sensor is provided on one or the other of the pair of surfaces of the cover.

14. The rotating device according to any one of claims 11 to 13, wherein a recess is formed on an outer circumferential surface of the rotating shaft, and a rotor of the angle sensor is fixed to the outer circumferential surface of the rotating shaft.

15. The rotating device according to claim 14, wherein the rotating shaft has a first outer peripheral surface, a second outer peripheral surface having a width smaller than that of the first outer peripheral surface in the radial direction, and a third outer peripheral surface having a width smaller than that of the second outer peripheral surface in the radial direction, and the recess is formed in the second outer peripheral surface.

16. The rotating device according to claim 15, wherein the first outer peripheral surface and the third outer peripheral surface at the position of the recess in the circumferential direction are curved surfaces.

17. The rotating device according to claim 14, wherein a rotor of the angle sensor is formed with a protrusion that is received in a recess of the rotating shaft.

Images