Angle sensor

Abstract

This angle sensor (1) comprises: a plurality of walls (11) extending in an axial line (x) direction; a plurality of spokes (12) connected to the plurality of walls (11); and a plurality of coils (20) wound around the plurality of spokes (12). The plurality of coils (20) face the plurality of walls (11) in the radial direction. The width (w11) of the wall (11) is equal to or greater than the width (w21) of the spoke (12) in the circumferential direction.

Description

Angle Sensor

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

[0002] Conventionally, various sensors have been used to detect the 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] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an angle sensor that can improve detection accuracy.

[0006] An angle sensor according to one aspect of the present invention comprises a plurality of walls extending in the direction of a rotation axis, a plurality of spokes connected to the plurality of walls, and a plurality of coils wound around the plurality of spokes, wherein the plurality of coils face the plurality of walls in the radial direction, and the width of the walls is the same as or greater than the width of the spokes in the circumferential direction.

[0007] 1 is a diagram schematically illustrating the configuration of an angle sensor according to an embodiment of the present invention, and is a partially transparent perspective view schematically illustrating the internal configuration through some members of the angle sensor. FIG. 1 is a perspective view schematically illustrating the configuration of the angle sensor. FIG. 2 is a front view schematically illustrating the configuration of the angle sensor. FIG. 3 is a side view schematically illustrating the configuration of the angle sensor. FIG. 4 is a partially enlarged view showing a portion surrounded by frame line A in FIG. 3. FIG. 5 is a perspective view schematically illustrating the configuration of a stator. FIG. 6 is a front view schematically illustrating the configuration of a stator. FIG. 7 is a perspective view showing an example of a coil structure formed by multiple coils. FIG. 8 is a diagram schematically illustrating the configuration of the coil structure shown in FIG. 9. FIG. 10 is an enlarged view of a wall and spokes. FIG. 11 is an enlarged view of a wall and spokes. FIG. 12 is an enlarged view of a wall and spokes. FIG. 13 is an enlarged view of a wall and spokes. FIG. 14 is an enlarged view of a wall and spokes. FIG. 15 is a diagram showing magnet wire forming multiple coils wound around multiple spokes. FIG. 16 is a perspective view showing a modified example of a 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 some of the reference numerals 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 partially transparent perspective view showing 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. FIG. 5 is a partially enlarged view showing the portion surrounded by the frame line A in FIG. 3. As shown in FIGS. 1 to 5, the angle sensor 1 includes a plurality of walls 11 extending in the direction of the axis x, a plurality of spokes 12 connected to the plurality of walls 11, and a plurality of coils 20 wound around the plurality of spokes 12. The plurality of coils 20 face the plurality of walls 11 in the radial direction. In the circumferential direction, the width w11 of the wall 11 is the same as or greater than the width w21 of the spokes 12. The following is a specific description of the configuration of the angle sensor 1. Note that the axis x is the rotation axis of the angle sensor 1. The radial direction is a direction perpendicular to the axis x.

[0009] As shown in FIGS. 1 to 4 , the angle sensor 1 specifically includes a rotor 2 and a stator 3. The rotor 2 includes a cylinder 30 and a conductor structure 4 fixed to the cylinder 30. A plurality of walls 11 and a plurality of spokes 12 are provided on the stator 3, and a plurality of coils 20 are attached to the stator 3 so as to cover the cylinder 30 from the outside in the radial direction (hereinafter also referred to as the "outer peripheral side"). The rotor 2 and the stator 3 face each other in the radial direction of the cylinder 30. Note that FIGS. 2 to 4 show the rotor 2 and the stator 3 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.

[0010] As shown in FIGS. 1 to 4 , the cylinder 30 of the rotor 2 is a cylindrical member extending along the axis x. Note that FIG. 1 shows the interior of the cylinder 30 in a see-through manner. The cylinder 30 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 30 of the rotor 2 has an inner circumferential surface 31, which is a cylindrical surface extending along a cylindrical surface with the axis x as its central axis, and an outer circumferential surface 32, which is a cylindrical surface facing away from the inner circumferential surface 31 on the outer periphery. The cylinder 30 also has end faces 33 and 34, which are surfaces facing in the respective directions in which the axis x extends. The inner circumferential surface 31 and the outer circumferential surface 32 extend between the end faces 33 and 34. The angle sensor 1 is applied to, for example, a motor, and the motor shaft passes through the inner circumferential surface 31 of the cylinder 30 of the rotor 2, and the rotor 2 is fixed to the shaft. The cylinder 30 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.

[0011] The conductor structure 4 is formed from conductors, and is composed of a plurality of conductors 5, as shown in FIG. 1 . The conductors 5 are arranged, for example, in a circumferential direction around the axis x. As shown schematically in FIG. 1 , the conductors 5 form a cylindrical conductor structure 4 extending annularly around the axis x. The conductors 5 may be any conductive material (a material capable of generating so-called eddy currents or induced currents (currents) within one surface), such as a metal body. The conductors 5 are arranged at a predetermined distance apart in the circumferential direction of the tube 30. In other words, two adjacent conductors 5 are spaced a predetermined distance apart around the axis x. The conductors 5 are arranged, for example, at equal or approximately equal angular intervals in the circumferential direction along a cylindrical surface whose central axis is the axis x. The conductors 5 have, for example, a curved shape. The conductors 5 may be connected to each other. The multiple conductors 5 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 conductors 5 may be electrically connected.

[0012] The plurality of conductors 5 are provided in a tube 30, as shown in Fig. 1, for example. The conductors 5 may be entirely embedded in the tube 30, or a portion of each conductor 5 may be exposed on the surface of the tube 30. The plurality of conductors 5 may also be attached to the surface of the tube 30, for example, to the outer peripheral surface 32. In this case, a portion of the conductor 5 may be embedded in the tube 30.

[0013] Fig. 6 is a perspective view schematically showing the configuration of the stator 3, and Fig. 7 is a front view schematically showing the configuration of the stator 3. As shown in Figs. 1 to 4, 6, and 7, the stator 3 has a cylindrical portion 41 that is a cylindrical part corresponding to the cylinder 30 of the rotor 2. The cylindrical portion 41 forms a space capable of accommodating the rotor 2 therein and has an inner circumferential surface 42 that defines this space. The inner circumferential surface 42 is a surface that follows a cylindrical surface extending along the axis x and faces the outer circumferential surface 32 of the cylinder 30 of the rotor 2 with an annular gap therebetween. The inner circumferential surface 42 is, for example, a cylindrical surface that extends along a cylindrical surface with the axis x as its central axis.

[0014] As shown in FIGS. 1 to 4, 6, and 7, the stator 3 has a mounting portion 44 that is attached to an external device as an application target. As shown in FIGS. 1 to 4, 6, and 7, the mounting portion 44 is provided, for example, on the outer peripheral surface 43 of the cylindrical portion 41 and protrudes outward from the cylindrical portion 41. The outer peripheral surface 43 of the cylindrical portion 41 is a cylindrical surface facing away from the inner peripheral surface 42. The mounting portion 44 also has a through hole 44a through which a fixing member such as a bolt is passed, allowing the mounting portion 44 to be attached to an external device via the fixing member. The stator 3 has, for example, three mounting portions 44. However, the number of mounting portions 44 of the stator 3 is not limited thereto. As shown in FIGS. 1 to 4, 6, and 7, the stator 3 also has a holding portion 45 that houses, for example, an electric circuit device having a circuit unit and a computing unit (not shown). 1 to 4, 6, and 7, the holding portion 45 extends from the outer peripheral surface 43 of the cylindrical portion 41 along the axis x in one direction of the axis x. The holding portion 45 is also provided between the multiple mounting portions 44 in the circumferential direction.

[0015] As described above, the stator 3 includes a plurality of walls 11 and a plurality of spokes 12. As shown in FIGS. 5 to 7 , the plurality of walls 11 and the plurality of spokes 12 are connected to each other to form a plurality of protrusions 10 that protrude toward the rotor 2. As shown in FIG. 5 , the plurality of protrusions 10 are portions that protrude radially inward (hereinafter also referred to as the "inner peripheral side") from the inner peripheral surface 42 of the cylindrical portion 41, and the protrusions 10 are provided on the inner peripheral surface 42, for example, at equal or approximately equal angular intervals around the axis x. In other words, the plurality of spokes 12 protrude inward from the inner peripheral surface 42 of the cylindrical portion 41, and the plurality of spokes 12 are provided on the inner peripheral surface 42, for example, at equal or approximately equal angular intervals around the axis x. As shown in FIG. 5 , the plurality of walls 11 are connected to the tips 12 a of the plurality of spokes 12, respectively. The tips 12 a of the spokes 12 are the inner peripheral ends of the spokes 12. The multiple walls 11 are arranged, for example, at equal or approximately equal angular intervals around the axis x. In this way, the multiple walls 11 are each radially opposed to the inner circumferential surface 42 of the tubular portion 41 via the multiple spokes 12. Specific configurations of the multiple walls 11 and the multiple spokes 12 will be described later.

[0016] 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 3 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 adhesive or the like.

[0017] The coil 20 is made of a conductive member 21. The multiple coils 20 are, for example, lined up and connected in a circumferential direction around the axis x. As schematically shown in FIG. 1 , the multiple coils 20 form a cylindrical shape (hereinafter referred to as a "coil structure") 6 extending annularly around the axis x. The coil structure 6 is a shape formed by the arrangement of the multiple coils 20. In the coil structure 6, the multiple coils 20 are, for example, lined up annularly so as to be aligned along an annular surface around the axis x. The multiple coils 20 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 20 has, for example, a shape that surrounds a space. Furthermore, each coil 20 has, for example, a shape that the space surrounded by each coil 20 follows an annular surface around the axis x.

[0018] FIG. 8 is a perspective view showing an example of a coil structure 6 formed by a plurality of coils 20. FIG. 9 is a diagram schematically showing the configuration of the coil structure 6 shown in FIG. 8. The coil 20 is, for example, a coil formed by winding a magnet wire 21 as a conductive member 21. As shown in FIGS. 1, 8, and 9, for example, the coil 20 is formed by winding the magnet wire 21 around a plurality of protrusions 10. The coil 20 has an annular shape wound around the radial direction r of the cylinder 30 and surrounds a planar space facing the radial direction. The coil structure 6 is formed by arranging a plurality of coils 20 around the axis x in the cylinder portion 41 of the stator 3. Note that the conductive member 21 forming the coil 20 is not limited to a magnet wire.

[0019] As shown in Figures 8 and 9, the coil structure 6 has two pieces (hereinafter referred to as coil structure pieces) 6a and 6b. The coil structure piece 6a is formed by a plurality of coils 20a, which are the above-mentioned coil 20, connected in series in an annular shape. Similarly, the coil structure piece 6b is formed by a plurality of coils 20b, which are the above-mentioned coil 20, connected in series in an annular shape. That is, in the coil structure piece 6a and the coil structure piece 6b, a plurality of annular coils 20a and 20b are arranged in the circumferential direction, respectively. Note that the coil structure piece 6a and the coil structure piece 6b are coated with, for example, an insulating material (an insulating film or coating) and are electrically insulated from each other. As shown in Figures 8 and 9, the coil structure piece 6a and the coil structure piece 6b overlap in the radial direction to form the coil structure 6. In the coil structure pieces 6a and 6b, a portion of the space surrounded by the coil 20a is offset in the circumferential direction from a portion of the space surrounded by the coil 20b, and another portion of the space surrounded by the coil 20a is overlapped in the circumferential direction. Specifically, the space surrounded by the coil 20a is offset in the circumferential direction from the space surrounded by the coil 20b by half the width of the space surrounded by the coil 20a. The number of coils 20a and 20b in each of the coil structure pieces 6a and 6b corresponds to the axial multiplier angle set for the angle sensor 1. The number of coil structure pieces 6a and 6b also corresponds to the number of detection signals output by the coil structure 6.

[0020] 5 and 9 , a magnet wire 21 as a conductive member is wound around each of the protrusions 10 in the radial direction r, and a plurality of annular coils 20 are formed around the plurality of protrusions 10 in the radial direction r, thereby forming a coil structure 6 in the stator 3. The magnet wire 21 is wound around the spokes 12 of the protrusions 10, as will be described later. For example, the coil structure pieces 6a, 6b are formed by winding one magnet wire 21a, 21b around the plurality of protrusions 10 of the cylindrical portion 41, respectively. Specifically, for example, the magnet wire 21a, 21b is wound around the protrusions 10 alternately from one side in the axial x direction and the other side in the axial x direction for every two adjacent protrusions 10 toward one side in the circumferential direction, and then turned back after making one full turn around the cylindrical portion 41, and the magnet wire 21a, 21b is wound around the protrusions 10 again toward the other side in the circumferential direction to form the coil structure pieces 6a, 6b. In this case, each of the coils 20a, 20b is formed around two of the protrusions 10. The coil structure pieces 6a and 6b are offset from each other by one of the protrusions 10 in the circumferential direction. Note that the coils 20a, 20b are not limited to being formed around two of the protrusions 10, and may be formed around other numbers of protrusions 10. Furthermore, although the magnet wire 21 (21a, 21b) is described as being wound around one turn, the winding pattern of the magnet wire 21 is not limited to this, and the magnet wire 21 may be wound around two or more turns. In other words, the coil formed by winding the magnet wire 21 may have, for example, one layer or multiple layers such as two, three, four, or five layers in the radial direction. If the number of turns or layers is large, the output signal or the signal to be detected (for example, the amplitude of the signal waveform) can be amplified.

[0021] As shown in Figures 5 and 9, each coil 20 (20a, 20b) formed by being wound around the multiple protrusions 10 of the tubular portion 41 extends linearly. That is, the portions of each coil 20 extending along each protrusion 10 on one side in the axial x direction and the other side in the axial x direction extend linearly. Furthermore, between two adjacent protrusions 10, the portions of the coil structure pieces 6a, 6b (magnet wires 21a, 21b) extending between one side in the axial x direction and the other side in the axial x direction intersect. Specifically, the magnet wires 21a, 21b intersect between two adjacent protrusions 10. The intersection of the portions of the coil structure pieces 6a, 6b (magnet wires 21a, 21b) connects the two adjacent coils 20 (20a, 20b).

[0022] Both ends of the magnet wire 21 wound around the protrusions 10 to form the multiple coils 20 are drawn out from the tubular portion 41. For example, as shown in Fig. 9, both ends 21a1 and 21a2 of the magnet wire 21a and both ends 21b1 and 21b2 of the magnet wire 21b are drawn out from between two adjacent protrusions 10. As shown in Fig. 9, as an example, the ends 21a1 and 21a2 of the magnet wire 21a and the ends 21b1 and 21b2 of the magnet wire 21b are drawn out through the gap between the first protrusion 10 and the second protrusion 10.

[0023] The rotor 2 and the stator 3 form an inductive angle sensor, and the multiple coils 20 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 20. Specifically, the stator 3 is provided with an excitation circuit 7 (see FIG. 4 ), which is a magnetic circuit that generates a periodically changing magnetic flux acting on each of the multiple coils 20. Meanwhile, the multiple conductors 5 are arranged circumferentially around the axis x as described above, and cross the magnetic flux generated by the excitation circuit 7 as the rotor 2 rotates. Furthermore, the radial projection of the conductor 5, which has a portion extending along the axis x, onto the coils 20 moves as the rotor 2 rotates. Therefore, the magnetic flux from the excitation circuit 7 acting on each of the multiple coils 20 is affected by eddy currents generated in the conductors 5 and cancels out, periodically changing as the rotor 2 rotates. As a result, in the plurality of coils 20, an electromotive force is generated by electromagnetic induction which varies with the rotation of the rotor 2, and signals which vary with the rotation of the rotor 2 are detected from the plurality of coils 20. Based on the detection signals from the plurality of coils 20, the rotation angle of the rotor 2 is detected in an external electric circuit device.

[0024] Next, the configuration of the wall 11 and the spokes 12 will be described in detail. Figures 10 to 14 are enlarged views of the wall 11 and the spokes 12. Figure 10 is a view of the wall 11 and the spokes 12 viewed in the radial direction. Figures 11 and 13 are views of the wall 11 and the spokes 12 viewed from one side in the direction of the axis x, and Figures 12 and 14 are views of the wall 11 and the spokes 12 viewed from the other side in the direction of the axis x.

[0025] 5 and 10 to 14, the protrusion 10 is formed by the wall 11 and the spokes 12, and the wall 11 is connected to the tips 12a of the spokes 12 protruding from the inner circumferential surface 42 of the cylindrical portion 41 of the stator 3. The circumferential width w11 of the wall 11 is the same as the circumferential width w21 of the spokes 12 (w11 = w21) or is larger than the circumferential width w21 of the spokes 12 (w11 > w21). In addition, the width of the wall 11 in the axial x direction (hereinafter referred to as width w12) is larger than the width of the spokes 12 in the axial x direction (hereinafter referred to as width w22) (w12 > w22).

[0026] As shown in FIGS. 10 to 14 , the spoke 12 has end portions 13a and 13b facing back to back in the circumferential direction, and end portions 13c and 13d facing back to back in the direction of the axis x. The end portions 13a and 13b are surfaces facing in the circumferential direction, respectively. The end portions 13c and 13d are surfaces facing in the direction in which the axis x extends, respectively. The end portions 13a and 13b extend, for example, along the axis x and have a constant or approximately constant width in the radial direction. Specifically, the end portions 13a and 13b extend, for example, parallel or approximately parallel to the axis x. The end portions 13c and 13d extend, for example, in the circumferential direction and have a constant or approximately constant width in the radial direction. Specifically, the end portions 13c and 13d extend, for example, in the circumferential direction so as to be parallel or approximately parallel to a plane perpendicular to the axis x. In this way, the spokes 12 protrude radially from the inner circumferential surface 42 of the cylindrical portion 41 of the stator 3, and have, for example, a rectangular or substantially rectangular cross section perpendicular to the radial direction. Note that the cross-sectional shape of the spokes 12 is not limited to a rectangle and may be other shapes.

[0027] As described above, the multiple spokes 12 are arranged at equal or approximately equal angular intervals around the axis x. As shown in FIGS. 11 to 13 , a gap 46 is formed between two adjacent spokes 12 in the circumferential direction. The circumferential width of the gap 46 between two adjacent spokes 12 in the circumferential direction is defined as width g1. The width g1 of the gap 46 between two spokes 12 is smaller than the circumferential width w21 of the spokes 12 (see FIG. 5 ) (g1<w21). The gap 46 is the circumferential gap between the end 13 a of one of the two circumferentially adjacent spokes 12 and the end 13 b of the other of the two circumferentially adjacent spokes 12. The width g1 is also the circumferential distance between the end 13 a of one of the two circumferentially adjacent spokes 12 and the end 13 b of the other of the two circumferentially adjacent spokes 12.

[0028] As shown in Figures 10 to 14, the wall 11 has end portions 14a and 14b that face each other in the circumferential direction, and end portions 14c and 14d that face each other in the direction of the axis x. The end portions 14a and 14b extend, for example, along the axis x and have a constant or approximately constant width in the radial direction. Specifically, the end portions 14a and 14b extend, for example, parallel or approximately parallel to the axis x. Furthermore, the end portions 14c and 14d extend, for example, in the circumferential direction and have a constant or approximately constant width in the radial direction. Specifically, the end portions 14c and 14d extend, for example, in the circumferential direction so as to be parallel or approximately parallel to a plane perpendicular to the axis x. Thus, the shape of the wall 11 when viewed in the radial direction is rectangular or approximately rectangular. Note that the shape of the wall 11 when viewed in the radial direction is not limited to a rectangle and may be other shapes. The wall 11 has a surface 15a facing the inner peripheral side, and the surface 15a faces the outer peripheral surface 32 of the cylinder 30 of the rotor 2 across an annular gap. The surface 15a of each of the multiple walls 11 extends, for example, along a cylindrical surface with the axis x as the central axis.

[0029] As described above, the multiple walls 11 are arranged at equal or approximately equal angular intervals around the axis x, and a gap 47 is formed between two adjacent walls 11 in the circumferential direction among the multiple walls 11. The circumferential width of the gap 47 between two adjacent walls 11 in the circumferential direction is width g2. The gap 47 communicates with the gap 46. The gap 47 is a circumferential gap between an end 14a of one wall 11 and an end 14b of the other wall 11 of two adjacent walls 11 in the circumferential direction. The width g2 is the circumferential distance between the end 14a of one wall 11 and the end 14b of the other wall 11 of two adjacent walls 11 in the circumferential direction.

[0030] 10 to 12 , in each protrusion 10, the radially extending ends 14a, 14b of the wall 11 and the radially extending ends 13a, 13b of the spokes 12 each extend continuously in the radial direction. That is, in each protrusion 10, the radially extending ends 14a, 14b of the wall 11 and the radially extending ends 13a, 13b of the spokes 12 are flush with each other. For example, in each protrusion 10, the end 14a of the wall 11 and the end 13a of the spoke 12 form a single plane or a nearly flat plane, and similarly, the end 14b of the wall 11 and the end 13b of the spoke 12 form a single plane or a nearly flat plane. The plane formed by the end 14a of the wall 11 and the end 13a of the spoke 12 extends, for example, on a radially extending plane that includes the axis x. Similarly, the surface formed by the end 14b of the wall 11 and the end 13b of the spoke 12 extends, for example, on a radially extending plane including the axis x. In this case, the width g2 of the gap 47 increases radially outward, and the width g1 of the gap 46 increases radially outward.

[0031] Furthermore, the plane formed by the end 14 a of the wall 11 of one of two circumferentially adjacent protrusions 10 and the end 13 a of the spokes 12 and the plane formed by the end 14 b of the wall 11 of the other of two circumferentially adjacent protrusions 10 and the end 13 b of the spokes 12 may be parallel or approximately parallel to each other. Specifically, for example, the plane formed by the end 14 a of the wall 11 of one of two circumferentially adjacent protrusions 10 and the end 13 a of the spokes 12 and the plane formed by the end 14 b of the wall 11 of the other of two circumferentially adjacent protrusions 10 and the end 13 b of the spokes 12 may be parallel or approximately parallel to a plane including the axis x passing midway between these planes in the circumferential direction. In this case, the width g2 of the gap 47 is constant or approximately constant in the radial direction, the width g1 of the gap 46 is constant or approximately constant in the radial direction, and the width g2 of the gap 47 and the width g1 of the gap 46 are the same or approximately the same.

[0032] In each protrusion 10, the shape of the radially continuous surface formed by the end 14 a of the wall 11 and the end 13 a of the spoke 12 is not limited to the shape described above. Similarly, in each protrusion 10, the shape of the radially continuous surface formed by the end 14 b of the wall 11 and the end 13 b of the spoke 12 is not limited to the shape described above.

[0033] The width g1 of the gap 46 between two circumferentially adjacent spokes 12 is large enough to accommodate the magnet wire 21 wound multiple times around the spokes 12 to form a plurality of coils 20. In this way, the gap 46 is configured to allow the magnet wire 21 to be wound around the spokes 12, but not to extend beyond the spokes 12 and wind around the wall 11. In this embodiment, the width g1 of the gap 46 is large enough to accommodate one intersection where the coils 20 are connected, and is wide enough to allow the magnet wire 21 to be wound around one turn. Note that as long as the wound magnet wire 21 does not come off the protrusion 10, a portion of the magnet wire 21 may be wound around the wall 11. Furthermore, as described above, the winding of the magnet wire 21 is not limited to one turn, and when the magnet wire 21 is wound around two or more turns, the gap 46 may have a width that allows the magnet wire 21 to be wound around two or more turns.

[0034] As described above, both ends 21a1 and 21a2 of the magnet wire 21a and both ends 21b1 and 21b2 of the magnet wire 21b are pulled out from between two adjacent protrusions 10, and as an example shown in Fig. 9, they are pulled out through the gap between the first protrusion 10 and the second protrusion 10. Therefore, for example, the ends 21a1 and 21a2 of the magnet wire 21a and the ends 21b1 and 21b2 of the magnet wire 21b are accommodated in a gap 47 connected to one gap 46 of the cylindrical portion 41. Furthermore, if there is space in the gap 46, the ends 21a1 and 21a2 of the magnet wire 21a and the ends 21b1 and 21b2 of the magnet wire 21b may also be accommodated in the gap 46.

[0035] 10 and 13, in each protrusion 10, an end 14c on one side of the wall 11 in the axis x direction protrudes further in the axis x direction than an end 13c on one side of the spoke 12 in the axis x direction. Also, as shown in Figures 10 and 14, in each protrusion 10, an end 14d on the other side of the wall 11 in the axis x direction protrudes further in the axis x direction than an end 13d on the other side of the spoke 12 in the axis x direction. Therefore, in each protrusion 10, a surface 15b is formed on the wall 11 extending between the end 14c and the end 13c and facing away from the surface 15a, as shown in Figure 13, and a surface 15c is formed on the wall 11 extending between the end 14d and the end 13d and facing away from the surface 15a, as shown in Figure 14. As a result, in each protrusion 10, a step is formed between the ends 13c, 13d of the spokes 12 and the ends 14c, 14d of the wall 11, with the surface 15b becoming the inner wall relative to the end 13c of the spoke 12, and the surface 15c becoming the inner wall relative to the end 13d of the spoke 12.

[0036] 10, 13, and 14, the ends 13c, 13d of the multiple spokes 12 are located closer to the interior of the protruding portion 10 in the direction of the axis x (toward the ends 13d, 13c facing away from them) than the side surfaces 41a, 41b of the tubular portion 41, forming recesses 16a, 16b that are recessed toward the interior of the protruding portion 10 in the direction of the axis x relative to the side surfaces 41a, 41b of the tubular portion 41. The side surfaces 41a, 41b of the tubular portion 41 are annular surfaces that face one side and the other side of the tubular portion 41 in the direction of the axis x, respectively, and extend between an inner circumferential surface 42 and an outer circumferential surface 43.

[0037] The ends 13c, 13d of the spokes 12 do not necessarily have to have the recesses 16a, 16b. For example, the ends 13c, 13d of the spokes 12 may be flush with the side surfaces 41a, 41b of the cylindrical portion 41, or may protrude toward the ends 14c, 14d in the direction of the axis x beyond the side surfaces 41a, 41b of the cylindrical portion 41.

[0038] As described above, the multiple coils 20 are wound around the multiple spokes 12. Specifically, the multiple coils 20 are wound around the multiple spokes 12 along the ends 13a, 13b, 13c, and 13d of the multiple spokes 12. As shown in FIG. 15 , the magnet wire 21 forming the multiple coils 20 extends along the ends 13c and 13d of the spokes 12 and the surfaces 15b and 15c of the wall 11. In this way, the magnet wire 21 forming the multiple coils 20 faces the surfaces 15b and 15c of the wall 11, and the multiple coils 20 face the wall 11 in the radial direction. In addition, the magnet wire 21 forming the multiple coils 20 extends in the gap 46 between two adjacent spokes 12 in the circumferential direction.

[0039] The magnet wires 21 forming the multiple coils 20 cross each other within the gap 46. That is, the magnet wires 21 extend between the end 13 c of one of two circumferentially adjacent spokes 12 and the end 13 d of the other of the two circumferentially adjacent spokes 12, and also between the end 13 d of one of two circumferentially adjacent spokes 12 and the end 13 c of the other of the two circumferentially adjacent spokes 12. In this way, the magnet wires 21 forming the multiple coils 20 are inclined in the gap 46 with respect to a direction parallel to the axis x. Also, the magnet wires 21 forming the multiple coils 20 cross each other within the gap 46.

[0040] The more consistent the output signals output by each of the multiple coils 20, the more accurate the detection accuracy of the angle sensor 1 and the more accurate the detection accuracy of the rotation angle of the rotor 2. Therefore, the more consistent the areas surrounded by each of the multiple coils 20, the more accurate the detection accuracy of the angle sensor 1. As described above, the magnet wires 21 forming the multiple coils 20 extend within the gap 46 at an inclination with respect to the direction parallel to the axis x. If the inclinations of the magnet wires 21 within the multiple gaps 46 with respect to the direction parallel to the axis x are different, variations will occur in the areas surrounded by each of the multiple coils 20. Therefore, a narrow range of inclination of the magnet wires 21 within the gap 46 with respect to the direction parallel to the axis x is preferable for improving the detection accuracy of the angle sensor 1. Furthermore, the more consistent the shapes of the multiple coils 20, the more accurate the detection accuracy of the angle sensor 1. As described above, the magnet wires 21 forming the multiple coils 20 intersect within the gap 46. When the positions at which the magnet wires 21 intersect within the gaps 46 (hereinafter referred to as intersecting positions P) are different from one another, the shapes of the coils 20 are different from one another. Therefore, in order to improve the detection accuracy of the angle sensor 1, it is preferable that the range of intersecting positions P of the magnet wires 21 that can be taken within the gaps 46 is narrow.

[0041] In the angle sensor 1, the extension direction of the magnet wires 21 forming the multiple coils 20 approaches a direction parallel to the axis x in the gap 46, and the inclination of the magnet wires 21 forming the multiple coils 20 with respect to a direction parallel to the axis x is small. Also, in the angle sensor 1, the intersection position P of the magnet wires 21 forming the multiple coils 20 in the gap 46 approaches the center position in the axis x direction, and the range of possible intersection positions P in the axis x direction is small.

[0042] Specifically, the width g1 of the gap 46 is reduced. For example, the aspect ratio (g1 / w22), which is the ratio of the circumferential width g1 of the gap 46 to the width (width w22) of the gap 46 in the axial x direction, is set to a predetermined value. Specifically, for example, the aspect ratio (g1 / w22) is less than 1 / 2 (g1 / w22<1 / 2) or less than 1 / 3 (g1 / w22≦1 / 3). Note that, as shown in FIGS. 10 and 15 , the width w22 is the width of the spoke 12 in the axial x direction, and is the distance in the axial x direction between the end 13c and the end 13d. Furthermore, for example, the width g1 of the gap 46 is reduced to a size such that the magnet wire 21 forming the multiple coils 20 passing through the gap 46 is not compressed by two circumferentially adjacent spokes 12.

[0043] As a result, in the gap 46, the inclination of the magnet wire 21 forming the multiple coils 20 with respect to the direction parallel to the axis x is reduced, and the direction in which the magnet wire 21 extends in the gap 46 approaches a direction parallel to the axis x. Also, in the gap 46, the magnet wire 21 forming the multiple coils 20 is restricted in movement between two circumferentially adjacent spokes 12. This also reduces the inclination of the magnet wire 21 forming the multiple coils 20 with respect to the direction parallel to the axis x in the gap 46, and the direction in which the magnet wire 21 extends in the gap 46 approaches a direction parallel to the axis x.

[0044] Furthermore, the intersection position P of the magnet wires 21 forming the multiple coils 20 in the gap 46 is within a predetermined range (range Δ) in the axial x direction from a center position (hereinafter referred to as center position P0) between the position of the portion of the magnet wire 21 along the end 13 c of the spoke 12 and the position of the portion of the magnet wire 21 along the end 13 d of the spoke 12 in the axial x direction (see FIG. 15 ). This predetermined range Δ is, for example, a range of 20% of the width (width w22) of the coils 20 in the axial x direction on both sides of the center position P0 in the axial x direction. Alternatively, this predetermined range Δ may be, for example, a range of 10% of the width (width w22) of the coils 20 in the axial x direction on both sides of the center position P0 in the axial x direction. This reduces variations in the output signals output by the multiple coils 20, improving the detection accuracy of the angle sensor 1 and the detection accuracy of the rotation angle of the rotor 2.

[0045] On the other hand, the intersection position P of the magnet wires 21 forming the multiple coils 20 in the gap 46 is not limited to the central position P0 in the axial x direction, and may be located anywhere. Specifically, the intersection position P may be located anywhere within the range of the width w22. Conventionally, there has been a problem of variation in the area of ​​the portion surrounded by the coils. However, in the angle sensor to which the present invention is applied, the width g1 of the gap 46 is set within the above range, so that the variation in the area of ​​the portion surrounded by the coils can be reduced. This makes it possible to suppress variation in the output signals output by each of the multiple coils 20, thereby improving the detection accuracy of the angle sensor 1 and the detection accuracy of the rotation angle of the rotor 2.

[0046] Furthermore, according to the angle sensor 1 of the embodiment of the present invention, the extension direction of the magnet wires 21 forming the plurality of coils 20 in the gap 46 can be made closer to a direction parallel to the axis x, and the inclination of the magnet wires 21 forming the plurality of coils 20 in the gap 46 with respect to a direction parallel to the axis x can be reduced. Therefore, it is possible to suppress variations in the output signals output by each of the plurality of coils 20, thereby improving the detection accuracy of the angle sensor 1 and the detection accuracy of the rotation angle of the rotor 2.

[0047] In this way, the angle sensor 1 according to the embodiment of the present invention can improve detection accuracy.

[0048] Furthermore, in each protrusion 10 of the angle sensor 1, the end 14a of the wall 11 and the end 13a of the spoke 12 form a surface that is continuous in the radial direction, and the end 13a of the spoke 12 does not form a groove recessed into the protrusion 10 relative to the end 14a of the wall 11. Similarly, the end 14b of the wall 11 and the end 13b of the spoke 12 form a surface that is continuous in the radial direction, and the end 13b of the spoke 12 does not form a groove recessed into the protrusion 10 relative to the end 14b of the wall 11. Therefore, the magnet wire 21 wound around the spoke 12 is not locked at the ends 13a, 13b. In contrast, each protrusion 10 has extending surfaces 15b, 15c that form steps between the ends 13c, 13d of the spoke 12 and the ends 14c, 14d of the wall 11, and the surfaces 15b, 15c are walls on the inner circumferential side relative to the ends 13c, 13d of the spokes 12, respectively. As a result, the magnet wire 21 wound around the spokes 12 is engaged at the ends 13c, 13d facing the surfaces 15b, 15c. Therefore, even if the ends 14a, 14b of the wall 11 and the ends 13a, 13b of the spokes 12 form a continuous surface in the radial direction, the magnet wire 21 wound around the spokes 12 is engaged at the surfaces 15b, 15c, making it easier to wind the magnet wire 21 around the spokes 12. Furthermore, the multiple coils 20 can be stably provided in the stator 3.

[0049] In the above-described embodiment, the stator 3 includes the cylindrical portion 41, 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. 16 is a perspective view showing a modified example of the stator 3. For example, as shown in FIG. 16, the stator 3 may be arc-shaped, or may extend only along a partial circumferential section of the entire circumference of the stator 3 described above. 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.

[0050] As shown in FIG. 16 , the stator 3 according to the modified example specifically includes, for example, a cylindrical portion 41, but instead includes an arc-shaped or substantially arc-shaped portion (hereinafter referred to as an arc portion) 41A corresponding to a circumferential section of the cylindrical portion 41. As shown in FIG. 16 , a plurality of protrusions 10 are formed in a row on the inner circumferential surface 42 of the arc portion 41A, similar to the stator 3 described above. The arc portion 41A has a plurality of protrusions 10 formed in a portion of the cylindrical portion 41 corresponding to the arc portion 41A. 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 20, similar to the detection coil (coil structure 6) provided in the stator 3 described above. Specifically, the plurality of coils 20 are arranged so as to form the coil structures 6a and 6b located in the portion of the cylindrical portion 41 corresponding to the arc portion 41A. In the stator 3 according to the modified example, like the plurality of coils 20 in the above-described stator 3, the plurality of coils 20 are formed by winding a conductive member such as a magnet wire around the protrusion 10. Like the above-described excitation circuit 7, the excitation circuit is a magnetic circuit that generates a periodically changing magnetic flux that acts on each of the plurality of coils 20 formed in the arc portion 41A.

[0051] Similarly to the stator 3 described above, the stator 3 according to the modified example also has mounting portions 44, 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 44 are provided, for example, at two circumferential ends of the arc portion 41A. 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 45 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 providing the excitation circuit and detection coil, contributing to improved detection accuracy. Furthermore, the electric circuit device and the excitation circuit or 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 44 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] For example, in each protrusion 10, the shape of the surface formed by the end 14 a of the wall 11 and the end 13 a of the spoke 12 is not limited to the shape described above. Similarly, in each protrusion 10, the shape of the surface formed by the end 14 b of the wall 11 and the end 13 b of the spoke 12 is not limited to the shape described above.

[0057] Specifically, for example, in each protrusion 10, the radially extending ends 14a, 14b of the wall 11 and the radially extending ends 13a, 13b of the spokes 12 do not have to extend continuously in the radial direction. In other words, in each protrusion 10, the radially extending ends 14a, 14b of the wall 11 and the radially extending ends 13a, 13b of the spokes 12 do not have to be flush with each other. Specifically, for example, in each protrusion 10, the ends 13a of the spokes 12 may be located closer to the inside of the protrusion 10 in the circumferential direction than the ends 14a of the wall 11 (towards the opposite ends 13b), and a groove may be formed that is recessed circumferentially toward the inside of the protrusion 10 relative to the ends 14a of the wall 11. Similarly, in each protrusion 10, the end 13b of the spoke 12 is located circumferentially closer to the inside of the protrusion 10 (towards the opposite end 13a) than the end 14b of the wall 11, and may form a groove that is recessed circumferentially toward the inside of the protrusion 10 relative to the end 14b of the wall 11.

[0058] 1 Angle sensor, 2 Rotor, 3 Stator, 4 Conductor structure, 5 Conductor, 6 Coil structure, 6a, 6b Coil structure piece, 7 Excitation circuit, 10 Protrusion, 11 Wall, 12 Spoke, 12a Tip, 13a, 13b, 13c, 13d, 14a, 14b, 14c, 14d End, 15a, 15b, 15c Surface, 16a, 16b Recess, 20, 20a, 20b Coil, 21, 21a, 21b Magnet wire, 21a1, 21a2, 21b1, 21b2 End, 30 Cylinder, 31 Inner peripheral surface, 32 Outer peripheral surface, 33, 34 End surface, 41 Cylinder portion, 41a, 41b Side, 42 Inner peripheral surface, 43 Outer peripheral surface, 44 Mounting portion, 44a Through hole, 45 Holding part, 46, 47 Gap, g1, g2 Width, w11, 12, 21, 22 Width, P Intersection position, P0 Center position, x Axis

Claims

1. An angle sensor comprising: a plurality of walls extending in a rotation axis direction; a plurality of spokes connected to the plurality of walls; and a plurality of coils wound around the plurality of spokes, wherein the plurality of coils face the plurality of walls in a radial direction; and wherein a width of the walls is the same as or greater than a width of the spokes in a circumferential direction.

2. The angle sensor according to claim 1, wherein the width of a gap between two adjacent spokes in the circumferential direction is smaller than the width of the spokes.

3. The angle sensor according to claim 1 or 2, wherein the ends of the walls extending in the radial direction and the ends of the spokes extending in the radial direction extend continuously in the radial direction.

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