Angle sensor and rotary device

Abstract

[Problem] To provide an angle sensor that is capable of suppressing the effects of movement in the axial direction of a rotation axis. [Solution] Provided is a side view schematically showing the configuration of an angle sensor 1. As shown in Fig. 1-4, the angle sensor 1 comprises a rotor 2 and a stator 3. The rotor 2 has a cylinder 10 and a plurality of metal bodies 20 that are fixed to the cylinder 10. The stator 3 has a plurality of coils 40. The rotor 2 has an outer circumferential surface 12 that faces the stator 3. In the circumferential direction, the plurality of metal bodies 20 are fixed to the outer circumferential surface 12 of the rotor 2.

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 cylinder, a rotor having a plurality of metal bodies fixed to the cylinder, and a stator having a plurality of coils, wherein the rotor has a surface facing the stator, and the metal bodies are fixed to the surface in the circumferential direction.

[0007] 14 is an exploded perspective view of a specific example of a rotating device to which an angle sensor is applied; FIG. 15 is an exploded perspective view of the rotating device shown in FIG. 14, which is provided with a cover according to a modified example; FIG. 16 is a perspective view showing the tip of the rotating shaft and its vicinity in the rotating device shown in FIG. 13; FIG. 17 is a perspective view of a specific example of a rotor of an angle sensor; FIG. 18 is a perspective view of a rotor of an angle sensor; FIG. 19 is a perspective view of a rotor of an angle sensor; FIG. 20 is a perspective view of a stator; FIG. 21 is a perspective view of a coil structure formed by a plurality of coils; FIG. 22 is a schematic view of the coil structure; FIG. 23 is a perspective view of a rotor; FIG. 24 is a diagram for explaining the function of a metal body provided on a rotor; FIG. 25 is a perspective view of a rotor having a metal body according to a modified example; FIG. 26 is a front view of a rotor according to a modified example; FIG. 27 is a front view of a rotor according to a modified example;

[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 an exploded perspective view showing 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 a plurality of metal bodies 20 serving as conductors fixed to the cylinder 10. The stator 3 includes a plurality of coils 40. The rotor 2 has an outer circumferential surface 12 that faces the stator 3. The plurality of metal bodies 20 are fixed to the outer circumferential surface 12 of the rotor 2 in the circumferential direction. 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 Figures 1 to 3, the multiple metal bodies 20 serving as conductors are arranged in the circumferential direction around the axis x, which is the axis of rotation of the angle sensor 1. The conductor may be a metal body or a member having a conductive material (a member 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 predetermined distances in the circumferential direction of the cylinder 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 surface of a cylinder whose central axis is the axis x.

[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, the cylinder 10 of the rotor 2 has an outer peripheral surface 12 that faces the stator 3. For example, as shown in FIGS. 1 to 4 , the outer peripheral surface 12 of the rotor 2 is a cylindrical surface extending along a cylindrical surface with the axis x as its central axis, and the cylinder 10 has an inner peripheral surface 11 that is a cylindrical surface facing away from the outer peripheral surface 12 on the radially inner side (hereinafter also referred to as the "inner peripheral side"). The radial direction is a direction perpendicular to the axis x. The cylinder 10 also has two end surfaces 13 and 14 that face in the respective directions along which the axis x extends. These two end faces 13, 14 form parts of two ends in the direction in which the axis x extends. The inner circumferential surface 11 and the outer circumferential surface 12 extend between the end faces 13 and 14. The angle sensor 1 is applied to, for example, a motor, whose shaft passes 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, a non-conductive material, or the like. 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, the multiple metal bodies 20 are fixed to the outer peripheral surface 12 of the tube 10. The metal bodies 20 are made of a conductive metal material. For example, the metal bodies 20 are fixed to the outer peripheral surface 12 of the tube 10 by adhesive bonding. However, the method of fixing the metal bodies 20 to the outer peripheral surface 12 of the tube 10 is not limited to adhesive bonding. For example, the tube 10 may be integrally formed of the metal bodies 20 and resin by insert molding, and the metal bodies 20 may be fixed to the outer peripheral surface 12 of the tube 10. Alternatively, for example, a recess having a shape corresponding to the shape of the metal body 20 may be provided on the outer peripheral surface 12 of the tube 10, the metal body 20 may be accommodated in this recess, and the metal body 20 may be fixed to the outer peripheral surface 12 by fixing the metal body 20 to the recess. In this case, the metal body 20 may be fixed to the tube 10 by a known method such as press-fitting or adhesive bonding. 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 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 that extends along the axis x and faces 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 that extends along a cylindrical surface whose central axis is the axis x.

[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] The stator 3 has a plurality of protrusions 30 protruding toward the rotor 2, as shown in, for example, FIGS. 1 to 3 and 5 . The protrusions 30 are portions that protrude inward (inward in the radial direction r) from the inner circumferential surface 31a of the cylindrical portion 31, as shown in, for example, FIG. 5 . 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 rectangle 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. 3, 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 a plurality of coils 40a, which are the above-mentioned coil 40, connected in series in an annular shape. Similarly, the coil structure piece 4b is formed by a plurality of coils 40b, which are the above-mentioned coil 40, connected in series in an annular shape. That is, a plurality of 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 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 from a portion of the space surrounded by the coil 40b in the circumferential direction, 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 from the space surrounded by the coil 40b in the circumferential direction 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 coil 40a, 40b is not limited to being formed around two protrusions 30, but may be formed around any other number 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 one layer in the radial or axial direction, two layers, three layers, four layers, or five layers. In this case, the detected signal or output signal (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, a non-conductive material, etc. 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. 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 bodies 20 will be described in detail. FIG. 8 is a perspective view of the rotor 2. As described above, the plurality of metal bodies 20 are fixed to the outer peripheral surface 12 of the cylinder 10 of the rotor 2 and are arranged in the circumferential direction. The metal bodies 20 are, for example, plate-shaped members, and extend in a direction along the outer peripheral surface 12 of the cylinder 10 as shown in FIG. 8. That is, the metal bodies 20 extend in a direction along the inner peripheral surface 31 a or the outer peripheral surface 31 b of the cylinder portion 31 of the stator 3. As described above, the metal bodies 20 have a curved shape. Specifically, the metal bodies 20 are curved along the outer peripheral surface 12 of the cylinder 10. That is, the metal bodies 20 are curved along the inner peripheral surface 31 a or the outer peripheral surface 31 b of the cylinder portion 31 of the stator 3.

[0024] For example, 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 and 24 extending between the edges of the outer surface 21 and the inner surface 22. These two end surfaces 23 and 24 form part of two ends of the metal body 20 in the axial x direction of the rotor 10. In this manner, the metal body 20 has a plate shape. The outer surface 21 is curved along the outer peripheral surface 12 of the cylinder 10. For example, the outer surface 21 extends parallel or approximately parallel to the outer peripheral surface 12 of the cylinder 10. The inner surface 22 extends parallel or approximately parallel to the outer surface 21, for example. The end surfaces 23 and 24 are back-to-back, face one side and the other side in the axial x direction, respectively, and extend in a curved manner along the outer surface 21. Moreover, end face 23 is curved so as to protrude in the direction of axis x opposite end face 24, and end face 24 is curved so as to protrude in the direction of axis x opposite end face 23. Furthermore, both circumferential ends of end face 23 and both circumferential ends of end face 24 are connected at acute angles at first end 25 and second end 26, respectively.

[0025] The shape of the metal body 20 when viewed from the radial direction is as described above, and the width (width W) of the metal body 20 in the axial direction x is smaller at the first end 25 than at the intermediate portion 20a between the first end 25 and the second end 26, and is also smaller at the second end 26 than at the intermediate portion 20a. For example, the width W of the metal body 20 is greatest at the intermediate portion 20a (width W0) and decreases circumferentially toward the first end 25 and similarly decreases circumferentially toward the second end 26, with the end faces 23 and 24 each extending along sinusoidal curves that protrude in opposite directions. In other words, the end faces 23 and 24 extend in directions that intersect and are inclined toward the first end 25 or the second end 26, respectively. Furthermore, for example, the metal body 20 has a symmetrical or approximately symmetrical shape with respect to a plane that passes through the centers of the end faces 23 and 24 and is parallel to the axis x, and also has a symmetrical or approximately symmetrical shape with respect to a plane that passes through the first end 25 and the second step end 26 and is perpendicular to the axis x. The metal body 20 has the shape described above, and when viewed from the radial direction of the metal body 20, it has a shape that is surrounded by two lines that protrude in opposite directions in a sinusoidal waveform.

[0026] Although the above description has been given of a case where the metal body 20 has a symmetric or approximately symmetric shape with respect to a plane that passes through the first end 25 and the second end 26 and is perpendicular to the axis x, the present invention is not limited to this. In other words, the end faces 23 and 24 may have asymmetric shapes with respect to a plane that passes through the first end 25 and the second step end 26 and is perpendicular to the axis x.

[0027] Each metal body 20 has a length L3 in the circumferential direction. The length L3 of the metal body 20 is greater than the lengths L1 and L2 of the annular coils 40a and 40b. The length L3 of the metal body 20 is equal to or less than the lengths L1 and L2 of the annular coils 40a and 40b. The length L3 of the metal body 20 in the circumferential direction is the distance between the first end 25 and the second end 26 in the circumferential direction perpendicular to the axis x, as shown in FIG. 8 . Meanwhile, the length L1,2 of each coil 40 in the circumferential direction is the length of the intersection 41 (41a, 41b) of each coil 40, which is the portion connecting two adjacent coils 40, in the circumferential direction perpendicular to the axis x (see FIGS. 5 and 7 ). The length L3 of the metal body 20 is equal to or greater than the sum of the lengths L1 and L2 of the annular coils 40a and 40b. In the circumferential direction, the distance between both ends of the metal body 20 is greater than the distance between both ends of the annular coils 40a, 40b. Furthermore, the width W0 of the middle portion 20a of the metal body 20 is equal to or greater than the length of both ends of the annular coils 40a, 40b in the direction of the axis x. However, without being limited to this, the length L3 of the metal body 20 may be adjusted to be smaller than the sum of the lengths L1, L2 of the annular coils 40a, 40b, or the lengths of both ends of the metal body 20 may be adjusted to be smaller than the lengths of both ends of the annular coils 40a, 40b.

[0028] 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 increased tension and linear (see Figures 5 to 7). Meanwhile, as described above, the metal body 20 has an outline that resembles two curved lines that protrude in opposite directions in a sinusoidal waveform, and the width W of the metal body 20 decreases from the intermediate portion 20a toward the first end 25 and the second end 26. Therefore, 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 in the circumferential direction of the metal body 20.

[0029] 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.

[0030] The function of the metal body 20 will be described in more detail. FIG. 9 is a diagram for explaining the function of the metal body 20. As shown in FIG. 9, two adjacent coils 40 are clockwise and counterclockwise coils, respectively (see FIG. 7), and the direction of current flow when viewed radially is different. When each metal body 20 is located in the center of the two adjacent coils 40 (state A in FIG. 9), the two adjacent coils 40 are each covered by the metal body 20 over an area of ​​the same size, and the two coils 40 are in a state of equilibrium. Therefore, the output of the coil structure 4 is 0.

[0031] As the rotor 2 further rotates and the metal body 20 moves further, the size of the area that the metal body 20 covers over one of the two coils 40 decreases, while the size of the area that the metal body 20 covers over the other of the two coils 40 increases (state B in Figure 9). At this time, because the metal body 20 has the shape described above, the rate at which the area that the metal body 20 covers over the coil 40 increases (increase rate) decreases, and the rate at which the area that the metal body 20 covers over the coil 40 decreases (decrease rate) decreases. As a result, the attenuation rate of the output from the two coils 40 decreases, the output obtained from the coil structure 4 gradually decreases, and the output waveform approaches a sine wave as shown in Figure 9.

[0032] As the rotor 2 further rotates and the metal body 20 moves further, the metal body 20 reaches a position where it covers only one of the coils 40 (state C in Figure 9). At this time, as shown in Figure 9, the output obtained from the coil structure 4, for example, reaches its maximum value on the positive side. As the rotor 2 further rotates and the metal body 20 moves further, an output waveform close to a sine wave is formed toward the maximum value on the negative side of the output obtained from the coil structure 4, similar to the above-mentioned output on the positive side. In this way, as the rotor 2 rotates, the detection of the coil structure 4 as described above is repeated, and an output close to a sine wave as shown in Figure 9 is repeatedly obtained.

[0033] 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 fixed to the outer peripheral surface 12 of 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.

[0034] Furthermore, the cylinder 10 of the rotor 2 is cylindrical and extends along the axis x, and even if the thickness of the cylinder 10 in the radial direction is reduced, the strength of the cylinder 10 against vibration in the direction of the axis x of the rotor 2 can be maintained high. Therefore, the thickness of the cylinder 10 in the radial direction can be reduced, making the rotor 2 lighter and reducing the installation space for the rotor 2.

[0035] 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 using magnet wire as a conductor, eliminating the need for connections between the coils 40.

[0036] 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.

[0037] Furthermore, since the metal body 20 has the shape described above and the width W decreases from the intermediate portion 20a toward the first end 25 and the second end 26, 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. This improves the accuracy of the angle sensor 1.

[0038] Next, a description will be given of a modified example of the metal body 20 of the rotor 2. Fig. 10 is a perspective view of the rotor 2 having a modified metal body 27. As shown in Fig. 10, the metal body 27 has a rectangular or substantially rectangular shape when viewed from the radial direction.

[0039] Next, another modification of the metal body 20 of the rotor 2 will be described. FIG. 11 is a perspective view of a rotor 2 having a metal body 28 according to another modification. Hereinafter, regarding the configuration of the metal body 28, components that are the same as or have similar functions to those of the above-described metal body 20 will be denoted by the same reference numerals and will not be described again, and only components that differ from the metal body 20 will be described. As shown in FIG. 11 , the first end 25 and the second end 26 of the metal body 28 form corners. A corner is, for example, a curved corner or corner. For example, as shown in FIG. 11 , in the metal body 28, the first end 25 is not a line like the first end 25 of the metal body 20, but is a surface facing in the circumferential direction. Similarly, for example, as shown in FIG. 11 , in the metal body 28, the second end 26 is not a line like the second end 26 of the metal body 20, but is a surface facing in the circumferential direction. Specifically, for example, the first end 25 extends along a plane perpendicular to the axis x, and the second end 26 extends along a plane perpendicular to the axis x. The first end face 25 and the second end face 26 do not have to extend along a plane. For example, they may extend along a curved or bent surface, or may have other shapes. Thus, in the metal body 28, corners 27a and 27b are formed between the first end 25 and the end faces 23 and 24, and corners 27c and 27d are formed between the second end 26 and the end faces 23 and 24. Therefore, peeling of the first end 25 and the second end 26 can be suppressed compared to a case where there are no corners. Furthermore, the corners 27a, 27b, 27c, and 27d allow the dimensions of the first end 25 and the second end 26 in the direction of the axis x to be increased, which facilitates manufacturing and suppresses tearing. The corners 27a, 27b, 27c, and 27d may also have a rounded shape.

[0040] Next, a modified example of the rotor 2 will be described. FIG. 12 is a front view of a rotor 5 according to the 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. 12 , the rotor 5 has a tube 16 that is different from the tube 10 of the rotor 2. The tube 16 has an outer peripheral surface 17 that is different from the outer peripheral surface 12 of the tube 10. The outer peripheral surface 17 of the tube 16 has protruding surfaces 17a that form portions that protrude outward corresponding to the multiple metal bodies 20. The same number of protruding surfaces 17a are formed as the number of metal bodies 20. As shown in FIG. 12 , the outer surface 21 of the metal body 20 has a shape that conforms to the protruding surfaces 17a of the tube 16. The multiple metal bodies 20 are respectively fixed to the multiple protruding surfaces 17a. The inner surfaces 22 of the multiple metal bodies 20 are in contact with the multiple protruding surfaces 17a. Metal bodies 27 and 28 shown in FIGS. 10 and 11 may be fixed to the protruding surface 17a of the rotor 5.

[0041] As described above, the outer peripheral surface 17 of the rotor 5, which faces the inner peripheral surface 31a of the stator 3, has the protruding surface 17a, so the radial distance between the inner peripheral surface 31a of the stator 3 and the outer peripheral surface 17 of the rotor 5 can be set to a non-uniform distance. Furthermore, the outer surface 21 of the metal body 20 is curved along the protruding surface 17a of the outer peripheral surface 17 of the rotor 5. In other words, the outer surface 21 of the metal body 20 is curved with respect to the inner peripheral surface 31a of the tubular portion 31 of the stator 3. 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 not uniform across the circumferential width of the outer surface 21 of the metal body 20. For example, the distance between the first end 25 and the second end 26 of the metal body 20 and the outer peripheral surface 12 of the cylinder 10 of the rotor 2 is larger than the distance between the middle part of the metal body 20 and the outer peripheral surface 12 of the cylinder 10 of the rotor 2, and the first end 25 and the second end 26 of the metal body 20 are further away from the outer peripheral surface 12 of the cylinder 10 of the rotor 2 than the middle part. Therefore, the effect of eddy currents generated in the metal body 20, which rotates as the rotor 5 rotates, on the magnetic flux from the excitation circuit 3a acting on each coil 40 is not uniform in the circumferential direction of the metal body 20.

[0042] In this way, even with the configuration of the metal body 20 curved relative to the inner peripheral surface 31 a of the stator 3, in addition to the configuration of the metal body 20 having the above-mentioned sinusoidal wave shape and projecting in opposite directions, the output waveform obtained from the detection signal detected from the coil structure 4 can be made closer to a sinusoidal wave, and the output waveform can be prevented from becoming a waveform close to a triangular wave. This improves the accuracy of the angle sensor 1.

[0043] Next, another modification of the rotor 2 will be described. FIG. 13 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. The following describes the components that differ from the rotor 2. As shown in FIG. 13 , the rotor 6 has a tube 18 that is different from the tube 10 of the rotor 2. Unlike the outer peripheral surface 12 of the tube 10, the outer peripheral surface 12 of the tube 18 is not cylindrical. Instead, it extends intermittently in the circumferential direction, with multiple portions of the outer peripheral surface 12 formed at positions spaced a predetermined distance apart in the circumferential direction. Furthermore, the tube 18 is formed with the same number of mounting surfaces 19 as the number of metal bodies 20, corresponding to the metal bodies 20. Furthermore, the multiple mounting surfaces 19 are provided, for example, at the same or approximately the same radial position, at equal or approximately equal angular intervals. The mounting surfaces 19 are curved relative to the outer peripheral surface 12.

[0044] Furthermore, as shown in Figure 13, between two adjacent mounting surfaces 19, a protrusion 18a is formed that protrudes outward from the mounting surfaces 19, and the protrusion 18a separates multiple outer peripheral surface portions, i.e., forms an interrupted outer peripheral surface 12.

[0045] In the rotor 6, the multiple metal bodies 20 are fixed to the multiple mounting surfaces 19, respectively. That is, the inner surface 22 of each metal body 20 is in contact with the corresponding mounting surface 19, and the inner surface 22 is fixed to the mounting surface 19. For example, the inner surface 22 is adhered to the mounting surface 19. The method of fixing the metal body 20 to the mounting surface 19 is not limited to adhesion. For example, the metal body 20 may be press-fitted between two adjacent protrusions 18a and fixed thereto. Furthermore, for example, the metal body 20 may be press-fitted between two adjacent protrusions 18a, and the inner surface 22 may be adhered to the mounting surface 19, and the metal body 20 may be fixed to the mounting surface 19.

[0046] In the rotor 6, the metal body 20 has a curved shape that conforms to the mounting surface 19. As shown in Fig. 13 , the curved shape of the metal body 20 is curved relative to, for example, the outer peripheral surface 12 of the cylinder 18. In other words, the curved shape of the metal body 20 is curved relative to, for example, the inner peripheral surface 31a or the outer peripheral surface 31b of the cylinder portion 31 of the stator 3.

[0047] Specifically, in a cross section perpendicular to the axis x, 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 16. Furthermore, in a cross section perpendicular to the axis x, the shape of the outer surface 21 of the metal body 20 is different from the shape of the outer peripheral surface 12 of the tube 16. In other words, in a cross section perpendicular to the axis x, the radius of curvature of the outer surface 21 of the metal body 20 is different from 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. Furthermore, in a cross section perpendicular to the axis x, the shape of the outer surface 21 of the metal body 20 is different from the shape of the inner peripheral surface 31 a or the outer peripheral surface 31 b of the tube portion 31 of the stator 3. For example, in a cross section perpendicular to the axis x, the radius of curvature of the outer surface 21 of the metal body 20 is smaller than the radius of curvature of the outer peripheral surface 12 of the tube 10, and in addition, in a cross section perpendicular to the axis x, the shape of the outer surface 21 of the metal body 20 is different from the shape of the outer peripheral surface 12 of the tube 16. In other words, in a cross section perpendicular to the axis x, the radius of curvature of the outer surface 21 of the metal body 20 is smaller than the radius of curvature of the inner peripheral surface 31 a of the tube portion 31 of the stator 3, and in addition, in a cross section perpendicular to the axis x, the shape of the outer surface 21 of the metal body 20 is different from the shape of the inner peripheral surface 31 a of the tube portion 31 of the stator 3.

[0048] When the outer surface 21 is curved relative to the outer peripheral surface 12 of the rotor 6, that is, curved relative to the inner peripheral surface 31 a of the cylindrical portion 31 of the stator 3, as in the case of the metal body 20 in the rotor 6, the radial distance between the outer surface 21 of the metal body 20 and the coils 40 or the space surrounded by the coils 40 is not uniform but varies across the circumferential width of the outer surface 21 of the metal body 20. Therefore, the influence of eddy currents generated in the metal body 20 that rotates as the rotor 6 rotates on the magnetic flux from the excitation circuit 3 a that acts on each coil 40 is not uniform but varies in the circumferential direction of the metal body 20.

[0049] In this way, by configuring the metal body 20 to be curved relative to the outer peripheral surface 12 of the rotor 6, in addition to the above-mentioned configuration of the metal body 20 having a sinusoidal wave shape and projecting in opposite directions, 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. This improves the accuracy of the angle sensor 1. Note that the metal bodies 27 and 28 shown in FIGS. 10 and 11 may be fixed to the rotor 6.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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 ).

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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. Boss portions 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 are formed in the cover 66 that penetrate between the surfaces 61 and 62, 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.

[0060] 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.

[0061] 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.

[0062] 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. 17, a recess 51b is formed on the outer circumferential surface of the tip 51a of the rotating shaft 51. Also, 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] As shown in FIG. 18 , the stator 3 according to the modified example specifically includes, for example, an arc-shaped or substantially arc-shaped portion (hereinafter referred to as the arc portion) 31A corresponding to a circumferential section of the cylindrical portion 31, instead of the cylindrical 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 cylindrical 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 structure pieces 4a, 4b located in the portion of the cylindrical 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 1 Angle sensor, 2, 5, 6 Rotor, 3 Stator, 3a Excitation circuit, 4 Coil structure, 4a, 4b Coil structure piece, 10, 16, 18 Cylinder, 11 Inner peripheral surface, 12, 17 Outer peripheral surface, 13, 14 End surface, 15 Projection, 17a Projection surface, 18a Projection, 19 Mounting surface, 20, 27, 28 Metal body, 20a intermediate part, 21 outer surface, 22 inner surface, 23, 24 end surface, 25 first end, 26 second end, 27a, 27b, 27c, 27d corner, 30 protrusion, 30a surface, 30b connecting part, 30c end, 31 cylinder part, 31A arc part, 31a inner peripheral surface, 31b Outer peripheral surface, 32 Mounting part, 32a Through hole, 33 Holding portion, 40, 40a, 40b Coil, 41, 41a, 41b Intersection portion, 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 surface, 56 Bearing, 57 Press-fit ring, 60, 66 Cover, 61, 62 Surface, 63 Boss, 64 Protrusion, 65 Bolt, 67 Through hole, L1, L2 L3 Length, x Axis, W, W0, W1, W2 Width

Claims

1. An angle sensor comprising: a cylinder, a rotor having a plurality of metal bodies fixed to the cylinder; and a stator having a plurality of coils, wherein the rotor has a surface facing the stator, and the metal bodies are fixed to the surface in the circumferential direction.

2. The angle sensor according to claim 1, wherein the plurality of metal bodies extend in a direction along the surface.

3. The angle sensor according to claim 2, wherein the surface has a protruding portion that protrudes toward the stator in a radial direction, and the metal body extends in a direction along the protruding portion.

4. The angle sensor according to claim 1, wherein the metal body comprises a first end, a second end, and a middle portion between the first end and the second end, and the width of the first end of the metal body in the direction of the rotation axis is smaller than the width of the middle portion of the metal body.

5. The angle sensor according to claim 4, wherein the width of the second end portion of the metal body in the direction of the rotation axis is smaller than the width of the middle portion of the metal body.

6. The angle sensor according to claim 4 or 5, wherein the first end or the second end of the metal body has a corner.

7. An angle sensor according to any one of claims 4 to 6, wherein the length of the metal body in the circumferential direction is the same as or smaller than the length of the coil.

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

9. The angle sensor according to claim 1, wherein the curved shapes of the plurality of metal bodies are curved relative to the outer circumferential surface of the tube.

10. The angle sensor according to any one of claims 1 to 9, wherein the radius of curvature of the metal body is different from the radius of curvature of the outer circumferential surface of the cylinder.

11. The angle sensor according to claim 10, wherein the radius of curvature of the metal body is smaller than the radius of curvature of the outer circumferential surface of the cylinder.

12. 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.

13. An angle sensor according to any one of claims 1 to 12, wherein the stator has a plurality of protrusions, and the plurality of coils are wound around the plurality of protrusions.

14. The angle sensor of claim 13, wherein a portion of the plurality of coils forms a coil structure connected around the rotor, and another portion of the plurality of coils forms another coil structure connected around the rotor, the portion of the plurality of coils and the other portion of the plurality of coils are offset from each other in the circumferential direction, and the portion of the plurality of coils and the other portion of the plurality of coils overlap each other in the radial direction.

15. An angle sensor according to any one of claims 1 to 14, wherein the rotor is disposed inside the stator.

16. A rotating device comprising: an angle sensor according to any one of claims 1 to 15; 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.

17. The rotating device according to claim 16, 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.

18. The rotating device according to claim 17, 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.

19. The rotating device according to any one of claims 16 to 18, 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.

20. The rotating device described in claim 19, 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.

21. The rotating device according to claim 20, 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.

22. The rotating device according to claim 19, wherein a rotor of the angle sensor is formed with a protrusion that is received in a recess of the rotating shaft.

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