Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system

Abstract

A magnetostrictive torque angle sensor 100 includes: a shaft 10 having a magnetostrictive part 12; and a magnetic pole part 101 arranged around the shaft 10. The magnetic pole part 101 is formed in an arc shape, and includes: a first magnetic pole stage 101A; and a second magnetic pole stage 101B arranged opposite the first magnetic pole stage 101A at an interval in an axial direction. The first magnetic pole stage 101A has a first protruding magnetic pole 110 protruding in a radial direction toward the shaft 10, and the second magnetic pole stage 101B has a second protruding magnetic pole 120 protruding in the radial direction toward the shaft 10 at a position different from that of the first protruding magnetic pole 110 in the circumferential direction. The first protruding magnetic pole 110 has an excitation coil 130 and an angle detection coil 150 wound therearound, and the second protruding magnetic pole 120 has a torque detection coil 140 wound therearound. The magnetic resistance between the magnetostrictive part 12 and the first protruding magnetic pole 110 changes periodically in conjunction with the rotation of the shaft 10.

Description

Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system

[0001] The present invention relates to a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system, and more particularly to a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that can detect torque and angle using the same sensor.

[0002] A magnetostrictive torque sensor is known that detects torque acting on a shaft due to rotation by detecting the magnetostrictive properties of a magnetostrictive film provided on the surface of the shaft. This magnetostrictive torque sensor has a magnetic path and windings oriented at +45° or −45° with respect to the shaft center, and is provided around the shaft.

[0003] When torque is applied to a shaft equipped with a magnetostrictive film, distortion occurs in the magnetostrictive film on the shaft surface, causing the permeability of the magnetostrictive film to change due to the Villari effect. This change in permeability of the magnetostrictive film causes the impedance of the magnetostrictive torque sensor to change. As a result, the magnetostrictive torque sensor can obtain a detection signal corresponding to the torque acting on the shaft from the change in impedance corresponding to the torque.

[0004] In order to detect not only the torque applied to a shaft but also the angle of the shaft, an angle sensor must be provided on the same shaft in addition to the torque sensor. This type of magnetostrictive torque angle sensor is described in Patent Document 1.

[0005] JP 2008-76066 A

[0006] In the case of the torque and angle sensor described in Patent Document 1, two physical sensors must be provided. As a result, there are problems in that the overall size of the sensor increases and the cost of two sensors is required. Furthermore, the increased number of parts may increase the probability of failure. For this reason, it is desirable to be able to detect torque and angle using a single sensor by sharing a stator, without physically providing two sensors.

[0007] Conventional magnetostrictive sensors are configured by arranging annular magnetic pole pieces around a shaft. This poses a problem in that the magnetic pole pieces cannot be easily replaced without removing the shaft. The present invention has been made to solve the above-mentioned problems, and aims to provide a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that can detect torque and angle using the same sensor and that allows for easy replacement of the magnetic pole pieces.

[0008] The magnetostrictive torque angle sensor of the present invention is a magnetostrictive torque angle sensor having a shaft with a magnetostrictive portion and a magnetic pole portion arranged around the shaft, wherein the magnetic pole portion is formed in an arc shape and includes a first magnetic pole stage and a second magnetic pole stage arranged opposite the first magnetic pole stage with an axial gap between them, the first magnetic pole stage having a first protruding magnetic pole that protrudes radially toward the shaft, and the second magnetic pole stage having a second protruding magnetic pole that protrudes radially toward the shaft at a circumferentially different position from the first protruding magnetic pole, an excitation coil and an angle detection coil are wound around the first protruding magnetic pole, and a torque detection coil is wound around the second protruding magnetic pole, and the magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole changes periodically as the shaft rotates.

[0009] In the magnetostrictive torque angle sensor according to the present invention, the magnetic resistance changes depending on whether the radial distance from the central axis of the shaft to the magnetostrictive portion changes periodically in the circumferential direction or whether the size of the magnetostrictive portion in the direction along the axis changes periodically in the circumferential direction.

[0010] In the magnetostrictive torque angle sensor of this invention, the mechanical central angle of the arc in the magnetic pole portion is set to an electrical angle of 360°, and the excitation coils are arranged at four first protruding magnetic poles in the first magnetic pole stage at intervals of 90° electrical angle, the angle detection coils are arranged at four first protruding magnetic poles in the first magnetic pole stage at intervals of 90° electrical angle, and the torque detection coils are arranged at two second protruding magnetic poles in the second magnetic pole stage at intervals of 180° electrical angle.

[0011] In the magnetostrictive torque angle sensor of this invention, the mechanical central angle of the arc in the magnetic pole portion is set to an electrical angle of 360°, and the excitation coil is arranged at at least one first protruding magnetic pole, the angle detection coil is arranged at at least two first protruding magnetic poles in the first magnetic pole stage, and the torque detection coil is arranged at two second protruding magnetic poles in the second magnetic pole stage, each of which has an electrical angle of 180°.

[0012] In the magnetostrictive torque angle sensor of this invention, the mechanical central angle of the arc in the magnetic pole portion is set to an electrical angle of 360°, and the excitation coil is arranged at least at two first protruding magnetic poles in the first magnetic pole stage, each of which has an electrical angle of 180°, the angle detection coil is arranged at least at two first protruding magnetic poles in the first magnetic pole stage, and the torque detection coil is arranged at one second protruding magnetic pole in the second magnetic pole stage.

[0013] The magnetostrictive torque angle sensing system of the present invention comprises the above-mentioned magnetostrictive torque angle sensor in which torque detection coils are arranged at two locations within the second pole stage, and a processing unit that processes torque detection signals from the torque detection coils and angle detection signals from the angle detection coils. The processing unit supplies an excitation signal to the excitation coil, detects the torque applied to the shaft based on the torque detection signal from the torque detection coil, and detects the angle of the shaft based on the angle detection signal from the angle detection coil.

[0014] The magnetostrictive torque angle sensing system of the present invention comprises the above-mentioned magnetostrictive torque angle sensor in which a torque detection coil is arranged at any one location within the second magnetic pole stage, and a processing unit that processes torque detection signals from the torque detection coil and angle detection signals from the angle detection coil. The processing unit supplies an excitation signal to the excitation coil, detects the angle of the shaft based on the angle detection signal from the angle detection coil, corrects the torque detection signal from the torque detection coil using the angle detection signal from the angle detection coil, and detects the torque applied to the shaft.

[0015] The magnetostrictive torque angle sensor according to the present invention is a magnetostrictive torque angle sensor having a shaft with a magnetostrictive portion and magnetic pole portions arranged around the shaft, the magnetic pole portions being formed in an arc shape and including a first magnetic pole stage and a second magnetic pole stage arranged opposite the first magnetic pole stage with a gap in the axial direction, the first magnetic pole stage having a plurality of first protruding magnetic poles protruding radially toward the shaft, and an excitation coil and an angle detection coil wound around at least four of the plurality of first protruding magnetic poles, The four-pole excitation coil is configured by alternately arranging first excitation coils and second excitation coils, and a first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil and the second excitation coil, respectively. The second magnetic pole stage has a second protruding magnetic pole that protrudes radially toward the shaft at a position different from the first protruding magnetic pole in the circumferential direction, and at least one pole of a torque detection coil is wound around the second protruding magnetic pole, and the magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole changes periodically as the shaft rotates.

[0016] In the magnetostrictive torque angle sensor according to the present invention, the magnetic resistance changes depending on whether the radial distance from the central axis of the shaft to the magnetostrictive portion changes periodically in the circumferential direction or whether the size of the magnetostrictive portion in the direction along the axis changes periodically in the circumferential direction.

[0017] In the magnetostrictive torque angle sensor according to the present invention, where n is an integer greater than or equal to 2, the first magnetic pole stage has an excitation coil and an angle detection coil wound around a first protruding magnetic pole of 2n poles, and the 2n-pole excitation coil is configured such that first excitation coils of n poles and second excitation coils of n poles are alternately arranged, one pole at a time, in the circumferential direction.

[0018] In the magnetostrictive torque angle sensor according to the present invention, a first excitation signal is supplied to the first excitation coil, and a second excitation signal whose phase differs from that of the first excitation signal by a certain angle is supplied to the second excitation coil.

[0019] In the magnetostrictive torque angle sensor according to the present invention, the torque detection coil is disposed in the second pole stage located midway between the first protruding poles of two adjacent poles in the circumferential direction.

[0020] A magnetostrictive torque angle sensing system according to the present invention comprises the magnetostrictive torque angle sensor described above, and a processing unit that processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil. The processing unit supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively, detects the torque applied to the shaft from the torque detection signal from the torque detection coil, and detects the angle of the shaft from the angle detection signal from the angle detection coil.

[0021] In the magnetostrictive torque angle sensing system according to the present invention, the processing unit corrects the torque detection signal using the angle detection signal to detect torque.

[0022] In the magnetostrictive torque angle sensor according to the present invention, arc-shaped magnetic pole portions are arranged around the axis, and a torque detection signal is obtained from the torque detection coil, and an angle detection signal is obtained from the angle detection coil. This makes it possible to provide a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that can detect torque and angle using the same sensor and whose magnetic pole portions are easily replaceable.

[0023] 1. A perspective view showing the configuration of the magnetostrictive torque angle sensor according to embodiment 1. A cross-sectional view showing a cross section taken along line II-II of FIG. 1. A cross-sectional view showing a cross section taken along line III-III of FIG. 1. An explanatory diagram showing the arrangement of first and second protruding magnetic poles of the magnetostrictive torque angle sensor according to embodiment 1, developed into a plane. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to embodiment 1. A characteristic diagram showing the magnetic resistance characteristics of the magnetostrictive torque angle sensor according to embodiment 1. A configuration diagram showing the configuration of a magnetostrictive torque angle sensing system according to embodiment 1. A characteristic diagram showing the output voltage characteristics obtained by processing the voltage generated in the torque detection coil during shaft rotation in the magnetostrictive torque angle sensor according to embodiment 1. 17 is a characteristic diagram showing output voltage characteristics obtained by processing the voltage generated in the angle detection coil when the shaft rotates in the magnetostrictive torque angle sensor according to embodiment 1. FIG. 18 is a characteristic diagram showing output voltage characteristics obtained by processing the voltage generated in the torque detection coil when torque is input in the magnetostrictive torque angle sensor according to embodiment 1. FIG. 19 is a characteristic diagram showing output voltage characteristics obtained by processing the voltage generated in the angle detection coil when torque is input in the magnetostrictive torque angle sensor according to embodiment 1. FIG. 19 is a perspective view showing the configuration of a magnetostrictive torque angle sensor according to embodiment 2. FIG. 19 is a cross-sectional view showing a cross section taken along line XVIII-XVIII of FIG. 17. FIG. 19 is a cross-sectional view showing a cross section taken along line XIX-XIX of FIG. 17. FIG. 19 is an explanatory diagram showing the arrangement of the first protruding magnetic poles and the second protruding magnetic poles of the magnetostrictive torque angle sensor according to embodiment 2, developed in a plane. FIG. 20 is a characteristic diagram showing the characteristics of the voltage obtained by processing the torque detection signal when the shaft rotates in the magnetostrictive torque angle sensing system according to embodiment 2.10A and 10B are characteristic diagrams showing characteristics of voltage obtained by processing an angle detection signal when a shaft rotates in the magnetostrictive torque angle sensing system according to Embodiment 2. FIG. 11A and 11B are characteristic diagrams showing characteristics of voltage obtained by processing a torque detection signal when torque is input in the magnetostrictive torque angle sensing system according to Embodiment 2. FIG. 11B are characteristic diagrams showing characteristics of voltage obtained by processing an angle detection signal when torque is input in the magnetostrictive torque angle sensing system according to Embodiment 2.

[0024] Hereinafter, embodiments of the magnetostrictive torque angle sensor 100 and the magnetostrictive torque angle sensing system 1 of the present invention will be described with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals.

[0025] First Embodiment. First, the basic configuration of a magnetostrictive torque angle sensor 100 according to the first embodiment will be described with reference to FIGS. 1 to 4. This first embodiment is based on Japanese Patent Application No. 2023-125353. [Configuration of the Magnetostrictive Torque Angle Sensor 100] FIG. 1 is a perspective view showing the configuration of the magnetostrictive torque angle sensor 100 according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is an explanatory diagram showing the arrangement of the first protruding magnetic pole 110 and the second protruding magnetic pole 120 of the magnetostrictive torque angle sensor 100 according to the first embodiment, developed in a plane.

[0026] The magnetostrictive torque angle sensor 100 mainly comprises a shaft 10 and a magnetic pole portion 101. The shaft 10 has a magnetostrictive portion 12 on its outer circumferential surface. The shaft 10 is held by a bearing or the like (not shown) and is configured to be rotatable relative to the magnetic pole portion 101. The shaft 10 rotates together with a test object (not shown) or is subjected to torque.

[0027] The magnetic pole portion 101 is formed in an arc shape and is arranged around the shaft 10. The magnetic pole portion 101 includes a first magnetic pole stage 101A and a second magnetic pole stage 101B arranged opposite the first magnetic pole stage 101A with a gap in the axial direction interposed therebetween via a gap adjustment portion 190.

[0028] An arc is a portion of a circumference. In this specification, an arc is also considered to exist when the outer or inner circumference of the magnetic pole portion 101 is not a portion of a smooth circumference but is a portion of a polygon, such as "7," ">," "V," "L," "]," or "]," or when the ends of the arc are extended, such as "U" or "J." The angle between the center of the circle that constitutes the arc and the two ends of the arc is defined as the central angle of the arc. In the first embodiment, the central angle of the arc is sometimes referred to as the mechanical central angle of the arc to distinguish it from the electrical angle described below. In the specific example shown in FIG. 1 , the magnetic pole portion 101 is formed with a central angle of approximately 180°. Theoretically, the central angle of the arc is greater than 0° and less than 360°. In reality, the central angle of the arc is preferably equal to or greater than a first central angle (e.g., about 30°) that satisfies a first condition that allows the provision of magnetic poles and coils, which will be described later, in the magnetostrictive torque angle sensor 100, and is preferably equal to or smaller than a second central angle (e.g., about 225°) that satisfies a second condition that allows the magnetic pole portion 101 to be easily attached to and detached from the shaft 10. It is also desirable that the magnetic reluctance of the shaft 10 periodically changes in accordance with the central angle of the arc.

[0029] The first pole stage 101A is provided with a plurality of first protruding magnetic poles 110 that protrude radially toward the shaft 10. In the specific example shown in FIG. 1 , four first protruding magnetic poles 110, 110a, 110b, 110c, and 110d, are provided at equal angular intervals as the first protruding magnetic poles 110. The second pole stage 101B is provided with second protruding magnetic poles 120 that protrude radially toward the shaft 10 and are provided at circumferentially different positions from the first protruding magnetic poles 110. In the specific example shown in FIG. 1 , two second protruding magnetic poles 120a and 120c are provided as the second protruding magnetic poles 120. Note that a second protruding magnetic pole (not shown) may be provided as the second protruding magnetic pole 120 at an intermediate position between the second protruding magnetic poles 120a and 120c.

[0030] An excitation coil 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110. In the specific example shown in FIGS. 1 to 4, an excitation coil 130a and an angle detection coil 150a are wound around the first protruding magnetic pole 110a, an excitation coil 130b and an angle detection coil 150b are wound around the first protruding magnetic pole 110b, an excitation coil 130c and an angle detection coil 150c are wound around the first protruding magnetic pole 110c, and an excitation coil 130d and an angle detection coil 150d are wound around the first protruding magnetic pole 110d. A torque detection coil 140 is wound around the second protruding magnetic pole 120. In the specific example shown in FIGS. 1 to 4, a torque detection coil 140a is wound around the second protruding magnetic pole 120a, and a torque detection coil 140c is wound around the second protruding magnetic pole 120c.

[0031] As shown in FIG. 4 , the mechanical central angle of the arc of the magnetic pole portion 101 is treated as a 360° electrical angle. The electrical angle is used to determine the arrangement of the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120a-120c, and the phases of the excitation signal, angle detection signal, and angle detection signal. The first protruding magnetic poles 110a-110d are arranged at 90° electrical angle intervals within a range of 360° electrical angle. The angular intervals between the first protruding magnetic poles 110a-110d are not strictly limited to 90° and may include slight variations or errors. The second protruding magnetic pole 120a is arranged circumferentially at a midpoint between the first protruding magnetic poles 110a-110b. The second protruding magnetic pole 120c is arranged circumferentially at a midpoint between the first protruding magnetic poles 110c-110d.

[0032] Therefore, horizontal magnetic paths H shown in Fig. 4 are formed between the first protruding magnetic pole 110a, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, between the first protruding magnetic pole 110b, the magnetostrictive portion 12, and the first protruding magnetic pole 110c, and between the first protruding magnetic pole 110c, the magnetostrictive portion 12, and the first protruding magnetic pole 110d. A first inclined magnetic path Diag_1 of approximately 45° shown in Fig. 4 is formed between the second protruding magnetic pole 120a, the magnetostrictive portion 12, and the first protruding magnetic pole 110a, and between the second protruding magnetic pole 120c, the magnetostrictive portion 12, and the first protruding magnetic pole 110c. A second inclined magnetic path Diag_2 of approximately -45° shown in Fig. 4 is formed between the second protruding magnetic pole 120a, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, and between the second protruding magnetic pole 120c, the magnetostrictive portion 12, and the first protruding magnetic pole 110d.

[0033] The figure shows a specific example of four excitation coils 130a to 130d. The excitation coil 130 needs to be arranged at least in two poles that form an electrical angle of 180° within the first magnetic pole stage 101A, and at the very least, it needs to be arranged in one location within the first magnetic pole stage 101A.

[0034] The angle detection coil 150 is shown as a specific example of four poles of angle detection coils 150a to 150d, and is composed of angle detection coils 150a and 150b of a first angle detection phase and angle detection coils 150c and 150d of a second angle detection phase. Note that the angle detection coil 150 may be composed of at least one of the angle detection coils 150a and 150b of the first angle detection phase and one of the angle detection coils 150c and 150d of the second angle detection phase.

[0035] Although the torque detection coil 140 is illustrated in two specific examples in the second magnetic pole stage 101B, where the torque detection coils 140a and 140c are positioned at an electrical angle of 180° from each other, it is sufficient that the torque detection coil 140 is positioned at at least one location in the second magnetic pole stage 101B.

[0036] [Magnetic Resistance Characteristics] Next, the configuration of the shaft 10 and its magnetic resistance characteristics will be described with reference to Figures 5 to 11. Figures 5 to 10 are diagrams showing the configuration of the shaft 10 of the magnetostrictive torque angle sensor 100 according to embodiment 1. Figure 11 is a characteristic diagram showing the magnetic resistance characteristics of the magnetostrictive torque angle sensor 100 according to embodiment 1.

[0037] In Fig. 5, the shaft 10 includes an inner shaft portion 11 and a magnetostrictive portion 12 provided on the outer periphery of the inner shaft portion 11, and is configured so that the radius of the shaft 10 changes periodically in the circumferential direction. As a result, the first magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic poles 110a to 110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic poles 120a and 120c change periodically with the rotation of the shaft 10, as shown in Fig. 11. Of the first and second magnetic resistances, it is desirable that the first magnetic resistance required for angle detection change periodically with the rotation of the shaft 10. For this reason, as shown in Fig. 6, it is sufficient that only the magnetostrictive region 12a on the shaft 10 facing the first protruding magnetic poles 110a to 110d has the cross-sectional shape shown in Fig. 5, and the magnetostrictive region 12b on the shaft 10 facing the second protruding magnetic poles 120a to 120c may have a perfectly circular cross-sectional shape. Here, shaft 10 is formed in one of the following ways. Shaft 10 is formed by providing magnetostrictive portion 12 as a magnetostrictive film on the outer peripheral surface of inner shaft portion 11 having the shape shown in FIG. 5 by coating, thermal spraying, or the like. Alternatively, shaft 10 is formed by press-fitting inner shaft portion 11 into magnetostrictive portion 12 as an outer cylindrical portion having the outer shape shown in FIG. 5 or 6. Alternatively, inner shaft portion 11 and magnetostrictive portion 12 may all be made of a magnetostrictive material, and the entire shaft 10 may be formed of magnetostrictive portion 12. Note that similar manufacturing methods can be applied to other forms of shaft 10 shown below.

[0038] In FIG. 7 , a magnetostrictive portion 12 is formed by coating, thermal spraying, or the like on a portion of the outer peripheral surface of the cylindrical inner shaft portion 11, at a position where the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120a-120c face the shaft 10. Alternatively, the inner shaft portion 11 is press-fitted into the magnetostrictive portion 12 as an outer cylindrical portion to form the shaft 10. Here, the magnetostrictive portion 12 is formed so that its axial size periodically varies in the circumferential direction. As a result, the first magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic poles 110a-110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic poles 120a-120c periodically vary with the rotation of the shaft 10, as shown in FIG. 7 . Note that the cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius periodically varies in the circumferential direction, as shown in FIG. 5 .

[0039] In FIG. 8, the magnetostrictive portion 12 formed by coating, thermal spraying, or the like on a portion of the outer circumferential surface of the inner shaft portion 11 has a magnetostrictive region 12a and a magnetostrictive region 12b. Here, the magnetostrictive region 12a is a region facing the first protruding magnetic poles 110a to 110d. The magnetostrictive region 12b is a region facing the second protruding magnetic poles 120a to 120c. The magnetostrictive region 12a is formed so that its axial size changes periodically in the circumferential direction. On the other hand, the magnetostrictive region 12b is formed so that its axial size does not change. As a result, the first magnetic resistance between the magnetostrictive region 12a and the first protruding magnetic poles 110a to 110d changes periodically with the rotation of the shaft 10, as shown in FIG. 11. On the other hand, the second magnetic resistance between the magnetostrictive region 12b and the second protruding magnetic poles 120a to 120c does not change with the rotation of the shaft 10 but remains constant. In FIG. 8, the cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius changes periodically in the circumferential direction as in FIG.

[0040] 9, a magnetostrictive portion 12 is formed by coating, thermal spraying, or the like on a part of the outer peripheral surface of the cylindrical inner shaft portion 11 at a position where the first protruding magnetic poles 110a to 110d and the second protruding magnetic poles 120a to 120c face the shaft 10. The axial size of the magnetostrictive portion 12 varies periodically in the circumferential direction and the magnetostrictive portion 12 protrudes from the inner shaft portion 11. As a result, the first magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic poles 110a to 110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic poles 120a to 120c vary periodically with the rotation of the shaft 10, as shown in FIG. 9. Note that in FIG. 9, the cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius varies periodically in the circumferential direction as shown in FIG. 5.

[0041] In FIG. 10 , the magnetostrictive portion 12 is formed on a portion of the outer circumferential surface of the inner shaft portion 11 by coating, thermal spraying, or the like, so as to protrude from the inner shaft portion 11. The magnetostrictive portion 12 has a magnetostrictive region 12a and a magnetostrictive region 12b. The magnetostrictive region 12a faces the first protruding magnetic poles 110a to 110d and is formed so that its axial size periodically changes in the circumferential direction. The magnetostrictive region 12b faces the second protruding magnetic poles 120a to 120c and is formed so that its axial size does not change. As a result, the first magnetic resistance between the magnetostrictive region 12a and the first protruding magnetic poles 110a to 110d changes periodically with the rotation of the shaft 10, as shown in FIG. 11 . On the other hand, the second magnetic resistance between the magnetostrictive region 12b and the second protruding magnetic poles 120a to 120c does not change with the rotation of the shaft 10 and remains constant. In FIG. 10, the cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius changes periodically in the circumferential direction as shown in FIG.

[0042] The cross-sectional shape of the shaft 10 shown in Figures 5 and 6, the shape of the magnetostrictive portion 12 shown in Figures 7 to 10, and the magnetic resistance change rate shown in Figure 11 are shown to follow a smooth sine wave shape, but are not limited to this. For example, instead of a sine wave, the cross-sectional shape of the shaft 10, the shape of the magnetostrictive portion 12 shown in Figures 6 and 7, and the magnetic resistance change rate shown in Figure 11 may be determined based on various periodic shapes such as a triangular wave, a rectangular wave, or a multi-step stepped wave.

[0043] [Processing of Magnetostrictive Torque Angle Sensing System 1] The magnetostrictive torque angle sensing system 1 will now be described with reference to Fig. 12. Fig. 12 is a diagram showing the configuration of the magnetostrictive torque angle sensing system 1 according to the first embodiment. The magnetostrictive torque angle sensing system 1 includes a magnetostrictive torque angle sensor 100 and a processing unit 200. Here, the magnetostrictive torque angle sensor 100 includes an excitation coil 130, a torque detection coil 140, and an angle detection coil 150, which are shown in relation to the processing unit 200.

[0044] The processing unit 200 supplies an excitation signal to the excitation coil 130. The processing unit 200 receives a torque detection signal from the torque detection coil 140, detects the torque applied to the shaft 10 from a voltage change in the torque detection signal, and outputs torque data. The processing unit 200 receives a plurality of angle detection signals from the angle detection coil 150, detects the angle of the shaft 10, and outputs angle data.

[0045] Hereinafter, angle detection signals and torque detection signals when the shaft 10 is rotating and when torque is input will be described in detail with reference to FIGS.

[0046] Torque detection when the shaft 10 rotates without torque input: FIG. 13 is a characteristic diagram showing the voltage characteristics generated in the torque detection coils 140a and 140c when the shaft 10 rotates without torque input in the magnetostrictive torque angle sensor 100 according to the first embodiment. FIG. 13 shows the torque detection signals generated in the torque detection coils 140a and 140c when the shaft 10 rotates without torque input. The torque detection signals generated in the torque detection coils 140a and 140c have a phase difference of 180°, and one cycle of voltage change occurs per 360° electrical angle. Therefore, the combined torque detection signal obtained by combining the torque detection signals generated in the torque detection coils 140a and 140c is flat with no voltage change. As a result, the processing unit 200 outputs torque data indicating torque = 0. In other words, even when the shaft 10 rotates, there is no effect on torque detection. If only one torque detection coil is used, it is not possible to obtain a flat characteristic as shown in FIG. 13 during rotation without torque. In this case, by correcting the torque detection signal using the angle detection signal, it is possible to obtain a flat characteristic as shown in FIG. 13, and to deal with this without any adverse effects on torque detection. Also, while the torque detection signal is shown in FIG. 13 as having a sinusoidal waveform, this is not limited thereto. If the waveform of the excitation signal supplied from the processing unit 200 to the excitation coil 130 and the magnetic resistance change rate of the shaft 10 have various periodic shapes such as a triangular wave, a rectangular wave, or a multi-step stepped wave, the torque detection signal will also have a waveform of a similar shape.

[0047] Angle detection when the shaft 10 rotates without torque input: FIG. 14 is a characteristic diagram showing the characteristics of the voltages generated in the angle detection coils 150a to 150d when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to the first embodiment. FIG. 14 shows the angle detection signals generated in the angle detection coils 150a to 150d when the shaft 10 rotates without torque input. The angle detection signal generated in the angle detection coils 150a and 150b (hereinafter referred to as the "first angle detection signal"), which constitutes the first angle detection phase, generates a voltage change of one cycle per 360° electrical angle. The angle detection signal generated in the angle detection coils 150c and 150d (hereinafter referred to as the "second angle detection signal"), which constitutes the second angle detection phase, has a phase difference of 90° with the first angle detection signal and generates a voltage change of one cycle per 360° electrical angle. Therefore, the processing unit 200 compares the amplitude values ​​of the first angle detection signal from the angle detection coils 150a and 150b with the second angle detection signal from the angle detection coils 150c and 150d to determine the angle during rotation of the shaft 10 and output the result as angle data. Note that although the angle detection signal is shown as having a sinusoidal waveform in Fig. 14, this is not limitative. If the waveform of the excitation signal supplied from the processing unit 200 to the excitation coil 130 and the magnetic resistance change rate of the shaft 10 have various periodic shapes such as a triangular wave, a rectangular wave, or a multi-step stepped wave, the angle detection signal will also have a waveform of a similar shape.

[0048] Torque detection when torque is input without rotating the shaft 10: FIG. 15 is a characteristic diagram showing the voltage characteristics generated in the torque detection coils 140a and 140c in the magnetostrictive torque angle sensor 100 according to embodiment 1 when torque is input to the shaft 10 without rotating. FIG. 15 shows the torque detection signals generated in the torque detection coils 140a and 140c when torque is input to the shaft 10 without rotating. Focusing on the torque detection signals obtained from the first inclined magnetic path Diag_1 and the second inclined magnetic path Diag_2 described in FIG. 4, the first torque detection signal obtained from the first inclined magnetic path Diag_1 and the second torque detection signal obtained from the second inclined magnetic path Diag_2 have different voltage change rates. A composite torque detection signal having a linear voltage change rate depending on the torque is obtained from the difference between the first torque detection signal obtained from the first inclined magnetic path Diag_1 and the second torque detection signal obtained from the second inclined magnetic path Diag_2. Therefore, the processing unit 200 calculates the input torque to the shaft 10 based on the composite torque detection signal and outputs it as torque data.

[0049] Angle detection when torque is input without rotating the shaft 10: FIG. 16 is a characteristic diagram showing the voltage characteristics generated in the angle detection coils 150a to 150d in the magnetostrictive torque angle sensor 100 according to embodiment 1 when torque is input to the shaft 10 without rotating. FIG. 16 shows the angle detection signals generated in the angle detection coils 150a to 150d when torque is input to the shaft 10 without rotating. The first angle detection signal generated in the angle detection coils 150a and 150b and the second angle detection signal generated in the angle detection coils 150c and 150d have the same torque characteristics. Therefore, the composite angle detection signal obtained by calculating the difference between the first and second angle detection signals is flat with no voltage change. This causes the processing unit 200 to output angle data indicating an angle of 0. In other words, even when torque is input to the shaft 10, the angle detection is not affected.

[0050] 13 to 16 have described the characteristics when the shaft 10 rotates without torque being input to the shaft 10, or when torque is input to the shaft 10 without rotation of the shaft 10. In reality, a situation may arise in which torque is input to the shaft 10 while the shaft 10 is rotating. In such a case, the processing unit 200 calculates both the angle and the torque by performing the processes described using FIGS. 13 to 16 in parallel.

[0051] [Changing the Number of Poles] In the first embodiment described above, the excitation coils 130a to 130d are wound around all of the first protruding magnetic poles 110a to 110d of the first magnetic pole stage 101A, but this is not limited to the magnetostrictive torque angle sensor 100. That is, it is sufficient that the excitation coils 130 are arranged around at least two poles that form an electrical angle of 180° within the first magnetic pole stage 101A, and at the very least, they are arranged at any one location within the first magnetic pole stage 101A.

[0052] In the first embodiment described above, the angle detection coils 150a to 150d are wound around all of the first protruding magnetic poles 110a to 110d of the first magnetic pole stage 101A, but the magnetostrictive torque angle sensor 100 is not limited to this. That is, the angle detection coil 150 may be configured with at least one of the angle detection coils 150a and 150b for the first angle detection phase and one of the angle detection coils 150c and 150d for the second angle detection phase.

[0053] In the first embodiment described above, the torque detection coils 140a and 140c are wound around the second protruding magnetic poles 120a and 120c of the second magnetic pole stage 101B. However, the magnetostrictive torque angle sensor 100 is not limited to this configuration. That is, the torque detection coil 140 may be disposed at at least one location within the second magnetic pole stage 101B. When reducing the number of excitation coils 130, torque detection coils 140, and angle detection coils 150, it is possible to eliminate the first protruding magnetic poles 110 in the first magnetic pole stage 101A where the excitation coils 130 and angle detection coils 150 are not present. Similarly, it is possible to eliminate the second protruding magnetic poles 120 in the second magnetic pole stage 101B where the torque detection coils 140 are not present.

[0054] [Advantages Obtained by First Embodiment] The advantages of the first embodiment are listed below. (1-1): The magnetostrictive torque angle sensor 100 described in the first embodiment is a magnetostrictive torque angle sensor 100 having a shaft 10 having a magnetostrictive portion 12 and a magnetic pole portion 101 arranged around the shaft 10, the magnetic pole portion 101 being formed in an arc shape and including a first magnetic pole stage 101A and a second magnetic pole stage 101B arranged opposite the first magnetic pole stage 101A with a gap in the axial direction, and the first magnetic pole stage 101A has a first protrusion protruding radially toward the shaft 10. The magnetostrictive torque angle sensor 100 has an output pole 110, and the second pole stage 101B has a second protruding magnetic pole 120 that protrudes radially toward the shaft 10 at a different circumferential position from the first protruding magnetic pole 110. An excitation coil 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110, and a torque detection coil 140 is wound around the second protruding magnetic pole 120, so that the magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 changes periodically with the rotation of the shaft 10. In this magnetostrictive torque angle sensor 100, a torque detection signal is obtained from the torque detection coil 140 and an angle detection signal is obtained from the angle detection coil 150 within the same sensor. Furthermore, by arranging the arc-shaped magnetic pole portions 101 around the shaft 10, replacement of the magnetic pole portions 101 is facilitated.

[0055] (1-2): In the magnetostrictive torque angle sensor 100 described in (1-1) above, the magnetic resistance is changed depending on whether the radial distance from the central axis of the shaft 10 to the magnetostrictive portion 12 changes periodically in the circumferential direction or whether the magnitude of the magnetostrictive portion 12 in the direction along the axis changes periodically in the circumferential direction. This makes it possible to detect not only torque but also angle using the same shaft 10 and magnetic pole portion 101.

[0056] (1-3): In the magnetostrictive torque angle sensor 100 described above in (1-1) and (1-2), the mechanical center angle of the arc in the magnetic pole portion 101 is set to 360° electrical angle, and the excitation coils 130 are arranged at four first protruding magnetic poles 110 at 90° electrical angle intervals within the first magnetic pole stage 101A, the angle detection coils 150 are arranged at four first protruding magnetic poles 110 at 90° electrical angle intervals within the first magnetic pole stage 101A, and the torque detection coils 140 are arranged at two second protruding magnetic poles 120 at 180° electrical angle intervals within the second magnetic pole stage 101B. This allows angle and torque to be detected without interference using a single sensor, and makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0057] (1-4): In the magnetostrictive torque angle sensor 100 described above in (1-1) to (1-3), the mechanical central angle of the arc in the magnetic pole portion 101 is set to an electrical angle of 360°, and the excitation coil 130 is disposed at at least one first protruding magnetic pole 110, the angle detection coil 150 is disposed at at least two first protruding magnetic poles 110 in the first magnetic pole stage 101A, and the torque detection coil 140 is disposed at two second protruding magnetic poles 120 in the second magnetic pole stage 101B, each of which corresponds to an electrical angle of 180°. This makes it possible to detect angle and torque without interference using a single sensor, and makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0058] (1-5): In the magnetostrictive torque angle sensor 100 described above in (1-1) to (1-3), the mechanical center angle of the arc of the magnetic pole portion 101 is defined as 360° electrical angle. The excitation coil 130 is disposed at least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A, where the excitation coil 130 corresponds to an electrical angle of 180°. The angle detection coil 150 is disposed at least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A. The torque detection coil 140 is disposed at one second protruding magnetic pole 120 in the second magnetic pole stage 101B. The torque detection signal from the torque detection coil 140 is corrected using the angle detection signal from the angle detection coil 150 to detect torque acting on the shaft 10. This allows even a single sensor with a minimal configuration to detect angle and torque without any adverse effects on torque detection and without interference, making it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0059] (1-6): The magnetostrictive torque angle sensing system 1 described in the first embodiment includes the magnetostrictive torque angle sensor 100 described in any one of (1-1) to (1-4) above, and a processing unit 200 that processes a torque detection signal from the torque detection coil 140 and an angle detection signal from the angle detection coil 150. The processing unit 200 supplies an excitation signal to the excitation coil 130, detects the torque applied to the shaft 10 based on the torque detection signal from the torque detection coil 140, and detects the angle of the shaft 10 based on the angle detection signal from the angle detection coil 150. In this magnetostrictive torque angle sensing system 1, the same sensor can obtain a torque detection signal from the torque detection coil 140 and an angle detection signal from the angle detection coil 150. Furthermore, by arranging the arc-shaped magnetic pole portions 101 around the shaft 10, replacement of the magnetic pole portions 101 becomes easy.

[0060] (1-7): The magnetostrictive torque angle sensing system 1 described in the first embodiment includes the magnetostrictive torque angle sensor 100 described in (1-5) above and a processing unit 200 that processes the torque detection signal from the torque detection coil 140 and the angle detection signal from the angle detection coil 150. The processing unit 200 supplies an excitation signal to the excitation coil 130, detects the angle of the shaft 10 based on the angle detection signal from the angle detection coil 150, and corrects the torque detection signal from the torque detection coil 140 using the angle detection signal from the angle detection coil 150 to detect the torque acting on the shaft 10. In this magnetostrictive torque angle sensing system 1, the same sensor obtains the torque detection signal from the torque detection coil 140 and the angle detection signal from the angle detection coil 150. Even a single sensor with a minimum configuration can detect angle and torque without any adverse effect on torque detection and without interference, making it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0061] Second Embodiment First, the basic configuration of a magnetostrictive torque angle sensor 100 according to a second embodiment will be described with reference to FIGS. 17 to 20. This second embodiment is based on Japanese Patent Application No. 2023-125354. [Configuration of the Magnetostrictive Torque Angle Sensor 100] FIG. 17 is a perspective view showing the configuration of the magnetostrictive torque angle sensor 100 according to the second embodiment. FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 17. FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. 17. FIG. 20 is an explanatory diagram showing the arrangement of the first protruding magnetic pole 110 and the second protruding magnetic pole 120 of the magnetostrictive torque angle sensor 100 according to the second embodiment, developed in a plane.

[0062] The magnetostrictive torque angle sensor 100 mainly comprises a shaft 10 and a magnetic pole portion 101. The shaft 10 has a magnetostrictive portion 12 on its outer circumferential surface. The shaft 10 is held by a bearing or the like (not shown) and is configured to be rotatable relative to the magnetic pole portion 101. The shaft 10 rotates together with a test object (not shown) or receives torque. The configuration and magnetic resistance characteristics of the shaft 10 are as described using FIGS. 5 to 11.

[0063] The magnetic pole portion 101 is formed in an arc shape and is arranged around the shaft 10. The magnetic pole portion 101 includes a first magnetic pole stage 101A and a second magnetic pole stage 101B. The second magnetic pole stage 101B is arranged opposite the first magnetic pole stage 101A with a gap in the axial direction therebetween via a gap adjustment portion 190.

[0064] An arc is a portion of a circumference. The angle between two ends of an arc and the center of a circle that includes the arc is the central angle of the arc. In the second embodiment, the central angle of an arc is sometimes referred to as the mechanical central angle of the arc to distinguish it from the electrical angle described below. Note that if the outer or inner circumference of the magnetic pole portion 101 is not part of a smooth circumference but is part of a polygon such as "7", ">", "V", "L", "]", or "]", or if the ends of the arc are extended such as "U" or "J", it is also treated as an arc.

[0065] In the specific example shown in Figure 17, the magnetic pole portion 101 is formed with an arc having a central angle of approximately 180°. Theoretically, the central angle of the arc is greater than 0° and less than 360°. In reality, the central angle of the arc is preferably equal to or greater than a first central angle (e.g., approximately 30°) that satisfies a first condition (described later) that allows the magnetostrictive torque angle sensor 100 to be provided with magnetic poles and coils, and is preferably equal to or smaller than a second central angle (e.g., approximately 225°) that satisfies a second condition (described later) that allows the magnetic pole portion 101 to be easily attached to and detached from the shaft 10. Furthermore, it is desirable for the magnetic resistance of the shaft 10 to change periodically in accordance with the central angle of the arc.

[0066] The first magnetic pole stage 101A is provided with a plurality of first protruding magnetic poles 110 that protrude radially toward the shaft 10. In the specific example shown in Fig. 17, the plurality of first protruding magnetic poles 110 include four first protruding magnetic poles 110a, 110b, 110c, and 110d that are provided at equal angular intervals.

[0067] The second pole stage 101B includes at least one second protruding magnetic pole 120 that protrudes radially toward the shaft 10 and is provided at a different circumferential position from the first protruding magnetic poles 110 (110a, 110b, 110c, and 110d). In the specific example shown in FIG. 17, one second protruding magnetic pole 120 is provided at a position corresponding to the midpoint between the first protruding magnetic poles 110b and 110c in the circumferential direction. The second protruding magnetic pole 120 may be located at a position corresponding to the midpoint between the first protruding magnetic poles 110a and 110b in the circumferential direction, or at a position corresponding to the midpoint between the first protruding magnetic poles 110c and 110d in the circumferential direction. The second protruding magnetic pole 120 may be two or more poles, instead of just one pole.

[0068] At least four excitation coils 130 and angle detection coils 150 are wound around each of the multiple first protruding magnetic poles 110. In the specific example shown in Figures 17 to 20, first protruding magnetic poles 110a, 110b, 110c, and 110d are provided as the multiple first protruding magnetic poles 110, and the excitation coil 130a and angle detection coil 150a are wound around the first protruding magnetic pole 110a, the excitation coil 130b and angle detection coil 150b are wound around the first protruding magnetic pole 110b, the excitation coil 130c and angle detection coil 150c are wound around the first protruding magnetic pole 110c, and the excitation coil 130d and angle detection coil 150d are wound around the first protruding magnetic pole 110d.

[0069] The at least four-pole excitation coil 130 is configured by alternatingly arranging first excitation coils 131 and second excitation coils 132. In the specific example shown in FIGS. 17 to 20, excitation coils 130a and 130c are the first excitation coils 131, and excitation coils 130b and 130d are the second excitation coils 132. A first excitation signal and a second excitation signal, which are out of phase with each other, are supplied to the first excitation coil 131 and the second excitation coil 132, respectively. The first excitation signal and the second excitation signal are realized, for example, by a sine-phase excitation signal and a cosine-phase excitation signal having a phase difference of 90°. Note that the sine-phase excitation signal and the cosine-phase excitation signal are merely examples, and various periodic waveforms, such as a triangular wave, a rectangular wave, or a multi-step stepped wave, may be used instead of the sine wave and the cosine wave. The phase difference between the first excitation signal and the second excitation signal is not limited to being strictly 90°.

[0070] As shown in FIG. 20 , the mechanical central angle of the arc of the magnetic pole portion 101 is treated as a 360° electrical angle. The electrical angle is used for the arrangement of the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120, the arrangement of the excitation coil 130, the arrangement of the torque detection coil 140, the arrangement of the angle detection coil 150, and the phases of the excitation signal, the angle detection signal, and the angle detection signal. In FIG. 20 , the first protruding magnetic poles 110a-110d are arranged at 90° electrical angle intervals within a range of 360° electrical angle. The second protruding magnetic pole 120 is arranged so as to be midway between the first protruding magnetic poles 110b-110c in the circumferential direction. The angular intervals of the first protruding magnetic poles 110a-110d are not strictly limited to 90° and may include slight variations or errors.

[0071] 20 , the first protruding magnetic poles 110a-110d and the second protruding magnetic pole 120 form a horizontal magnetic path H, a first inclined magnetic path Diag_1, and a second inclined magnetic path Diag_2 as follows: The horizontal magnetic path H is formed between the first protruding magnetic pole 110a, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, between the first protruding magnetic pole 110b, the magnetostrictive portion 12, and the first protruding magnetic pole 110c, and between the first protruding magnetic pole 110c, the magnetostrictive portion 12, and the first protruding magnetic pole 110d. The first inclined magnetic path Diag_1 is formed in a direction of approximately 45° between the second protruding magnetic pole 120, the magnetostrictive portion 12, and the first protruding magnetic pole 110b. The second inclined magnetic path Diag_2 is formed in a direction of approximately −45° between the second protruding magnetic pole 120, the magnetostrictive portion 12, and the first protruding magnetic pole 110c.

[0072] 17 to 20, four-pole excitation coils 130a to 130d and angle detection coils 150a to 150d are wound around the first protruding magnetic poles 110a to 110d, which are arranged at 90° electrical angle intervals within a range of 360° electrical angle. Note that within the first magnetic pole stage 101A, the four first protruding magnetic poles 110 can be arranged at angular intervals narrower than 90° electrical angle. Specifically, the four first protruding magnetic poles 110 can be arranged at intervals of approximately 80° to 85° electrical angle, which is narrower than 90° electrical angle.

[0073] [Processing of Magnetostrictive Torque Angle Sensing System 1] The processing of the magnetostrictive torque angle sensing system 1 according to the second embodiment will be described below. The configuration and operation of the magnetostrictive torque angle sensing system 1 are as described with reference to Fig. 12. Hereinafter, the angle detection signal and torque detection signal when the shaft 10 is rotating and when torque is input will be described in detail with reference to Figs. 21 to 24.

[0074] Torque detection when the shaft 10 rotates without torque input: FIG. 21 is a characteristic diagram showing voltage characteristics obtained by processing the torque detection signal when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to embodiment 2. Specifically, FIG. 21 shows characteristics obtained by correcting the torque detection signal using the angle detection signal in the processing unit 200 when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to embodiment 2. Here, the processing unit 200 outputs torque data indicating torque = 0 when the shaft 10 rotates without torque input. In other words, even if the torque detection coil 140 has only one pole or multiple poles positioned circumferentially unbalanced, the rotation of the shaft 10 does not adversely affect torque detection. Note that if the torque detection coil 140 has multiple poles positioned circumferentially balanced, the processing unit 200 can output torque data indicating torque = 0 without correcting the torque detection signal using the angle detection signal.

[0075] Angle detection when the shaft 10 rotates without torque input: FIG. 22 is a characteristic diagram showing voltage characteristics obtained by processing the angle detection signal when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to embodiment 2. Specifically, FIG. 22 shows characteristics of the phase shift and rotation angle obtained by comparing the angle detection signal with the excitation signal in the processing unit 200 when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to embodiment 2. As shown in FIG. 22 , the phase shift between the angle detection signal and the excitation signal is proportional to the rotation angle of the shaft 10. Therefore, the processing unit 200 creates a table of phase shifts and rotation angles in advance, calculates the phase shift between the angle detection signal and the excitation signal, and applies the phase shift to the table to calculate the angle of the shaft 10 during rotation, outputting the angle data.

[0076] Torque detection when torque is input without rotating the shaft 10: Fig. 23 is a characteristics diagram showing voltage characteristics obtained by processing the torque detection signal in the magnetostrictive torque angle sensing system 1 according to embodiment 2 when torque is input to the shaft 10 without rotating the shaft 10. Specifically, Fig. 23 shows voltage characteristics obtained by processing the torque detection signal in the processing unit 200 in the magnetostrictive torque angle sensing system 1 according to embodiment 2 when torque is input to the shaft 10 without rotating the shaft 10. Focusing on the torque detection signals obtained from the first inclined magnetic path Diag_1 and the second inclined magnetic path Diag_2 described in Fig. 20, the first torque detection signal obtained from the first inclined magnetic path Diag_1 and the second torque detection signal obtained from the second inclined magnetic path Diag_2 have different voltage change rates. Therefore, a composite torque detection signal having a linear voltage change rate depending on torque is obtained from the difference between the first torque detection signal obtained from the first inclined magnetic flux path Diag_1 and the second torque detection signal obtained from the second inclined magnetic flux path Diag_2. That is, the processing unit 200 calculates the input torque to the shaft 10 based on the composite torque detection signal and outputs the calculated torque data.

[0077] Angle detection when torque is input without rotating the shaft 10: FIG. 24 is a characteristic diagram showing the voltage characteristics obtained by processing the angle detection signal when torque is input to the shaft 10 without rotating in the magnetostrictive torque angle sensing system 1 according to embodiment 2. Specifically, FIG. 24 shows the characteristics of the phase shift and rotation angle obtained by comparing the angle detection signal with the excitation signal in the magnetostrictive torque angle sensing system 1 according to embodiment 2 when torque is input to the shaft 10 without rotating. As shown in FIG. 24 , the phase shift between the angle detection signal and the excitation signal is zero regardless of the torque input. Therefore, the processing unit 200 uses a table to apply a phase shift of zero to the table and outputs angle data indicating a rotation angle of zero. In other words, even when torque is input to the shaft 10, there is no effect on the angle detection.

[0078] 21 to 24 have described the characteristics when the shaft 10 rotates without torque being input to the shaft 10, or when torque is input to the shaft 10 without rotation of the shaft 10. In reality, a situation may arise in which torque is input to the shaft 10 while the shaft 10 is rotating. In such a case, the processing unit 200 can calculate both the angle and the torque by performing the processes described using FIGS. 21 to 24 in parallel.

[0079] [Changing the Number of Poles] In the second embodiment described above, the four-pole excitation coils 130a to 130d and the four-pole angle detection coils 150a to 150d are wound around the four first protruding magnetic poles 110a to 110d of the first magnetic pole stage 101A, but this is not limited to this. That is, it is possible to increase the number of poles of the excitation coil 130 and the angle detection coil 150 without being limited to the specific examples shown in FIGS. 17 to 20 .

[0080] Assuming that the mechanical central angle of the arc in the magnetic pole portion 101 is 360° electrical angle and n is a positive integer greater than or equal to 2, it is possible to provide 2n first protruding magnetic poles 110 at intervals of (360 / 2n) electrical angle degrees in the first magnetic pole stage 101A, and to wind excitation coils 130 and angle detection coils 150 around the 2n first protruding magnetic poles 110. In this case, the first excitation coils 131 and second excitation coils 132 are alternately arranged at intervals of (360 / 2n) electrical angle degrees. Note that it is also possible to provide the 2n first protruding magnetic poles 110 at angular intervals narrower than (360 / 2n) electrical angle degrees in the first magnetic pole stage 101A. Specifically, when n = 4, it is possible to provide eight first protruding magnetic poles 110 at intervals of approximately 40° electrical angle, which is narrower than (360 / 8)° = 45°. This makes it possible to use any number of excitation coils 130 and angle detection coils 150 to detect angle and torque with a single sensor without interference, and also makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10. It is also possible to provide, within the first magnetic pole stage 101A, first protruding magnetic poles 110 on which the first excitation coils 131 and second excitation coils 132 are not wound more than 2n times.

[0081] [Advantages Obtained by Second Embodiment] The advantages of the second embodiment are listed below. (2-1): The magnetostrictive torque angle sensor 100 described in the second embodiment has a shaft 10 having a magnetostrictive portion 12 and a magnetic pole portion 101 arranged around the shaft 10. The magnetic pole portion 101 is formed in an arc shape and includes a first magnetic pole stage 101A and a second magnetic pole stage 101B arranged opposite the first magnetic pole stage 101A with a gap in the axial direction. The first magnetic pole stage 101A has a plurality of first protruding magnetic poles 110 protruding radially toward the shaft 10, and an excitation coil 130 and an angle detection coil 150 are wound around at least four of the plurality of first protruding magnetic poles 110. The at least four excitation coils 130 are configured by alternatingly arranging first excitation coils 131 and second excitation coils 132, and a first excitation signal and a second excitation signal of different phases are supplied to the first excitation coils 131 and the second excitation coils 132, respectively. The second magnetic pole stage 101B has a second protruding magnetic pole 120 protruding radially toward the shaft 10 at a position different from the first protruding magnetic poles 110 in the circumferential direction, and a torque detection coil 140 of at least one pole is wound around the second protruding magnetic pole 120. The magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 is configured to change periodically as the shaft 10 rotates. In this magnetostrictive torque angle sensor 100, a torque detection signal is obtained from the torque detection coil 140 and an angle detection signal is obtained from the angle detection coil 150, all in the same sensor. Furthermore, by arranging the arc-shaped magnetic pole portions 101 around the shaft 10, replacement of the magnetic pole portions 101 becomes easy.

[0082] (2-2): In the magnetostrictive torque angle sensor 100 described in (2-1) above, the magnetic resistance is changed depending on whether the radial distance from the central axis of the shaft 10 to the magnetostrictive portion 12 changes periodically in the circumferential direction or whether the magnitude of the magnetostrictive portion 12 in the direction along the axis changes periodically in the circumferential direction. This makes it possible to detect not only torque but also angle using the same shaft 10 and magnetic pole portion 101.

[0083] (2-3): In the magnetostrictive torque angle sensor 100 described above in (2-1) to (2-2), where n is an integer equal to or greater than 2, the first magnetic pole stage 101A has an excitation coil 130 and an angle detection coil 150 wound around the 2n-pole first protruding magnetic pole 110, and the 2n-pole excitation coil 130 is configured such that n-pole first excitation coils 131 and n-pole second excitation coils 132 are alternately arranged in the circumferential direction. This makes it possible to use excitation coils 130 and angle detection coils 150 with any number of poles to detect angle and torque with a single sensor without interference, and makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0084] (2-4): In the magnetostrictive torque angle sensor 100 described above in (2-1) to (2-3), a first excitation signal is supplied to the first excitation coil 131, and a second excitation signal that is 90° out of phase with the first excitation signal is supplied to the second excitation coil 132. This makes it possible to detect angle and torque without interference using a single sensor, and makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0085] (2-5): In the magnetostrictive torque angle sensor 100 described above in (2-1) to (2-4), the torque detection coil 140 is disposed in the second magnetic pole section 101B, which is located midway between two adjacent first protruding magnetic poles 110 in the circumferential direction. This makes it possible to detect not only angle but also torque using the same shaft 10 and magnetic pole section 101. This allows a single sensor to detect angle and torque without interference, and makes it easy to replace the magnetic pole section 101 with respect to the shaft 10.

[0086] (2-6): The magnetostrictive torque angle sensing system 1 described in the second embodiment includes the magnetostrictive torque angle sensor 100 described in any one of (2-1) to (2-5) above, and a processing unit 200 that processes the torque detection signal from the torque detection coil 140 and the angle detection signal from the angle detection coil 150. The processing unit 200 supplies a first excitation signal and a second excitation signal, which are out of phase with each other, to the first excitation coil 131 and the second excitation coil 132, respectively, detects the torque applied to the shaft 10 based on the torque detection signal from the torque detection coil 140, and detects the angle of the shaft 10 based on the angle detection signal from the angle detection coil 150. This makes it possible to realize a magnetostrictive torque angle sensor 100 and a magnetostrictive torque angle sensing system 1 that are easily replaceable and can detect both torque and angle using the same sensor.

[0087] (2-7): In the magnetostrictive torque angle sensing system 1 described in (2-6) above, the processing unit 200 corrects the torque detection signal using the angle detection signal to detect torque. Even if the torque detection coil 140 has only one pole or multiple poles that are circumferentially unbalanced, the correction prevents the rotation of the shaft 10 from adversely affecting torque detection. This allows for the realization of a magnetostrictive torque angle sensor 100 and magnetostrictive torque angle sensing system 1 that are easily replaceable and capable of detecting both torque and angle using the same sensor.

[0088] 1 Magnetostrictive torque angle sensing system, 10 Shaft, 11 Inner shaft portion, 12 Magnetostrictive portion, 100 Magnetostrictive torque angle sensor, 101 Magnetic pole portion, 101A First magnetic pole stage, 101B Second magnetic pole stage, 110, 110a to 110d First protruding magnetic pole, 120, 120a, 120c Second protruding magnetic pole, 130, 130a to 130d Excitation coil, 131 First excitation coil, 132 Second excitation coil, 140, 140a, 140d Torque detection coil, 150, 150a to 150d Angle detection coil, 190 Spacing adjustment unit, 200 Processing unit, H Horizontal magnetic path, Diag_1 First inclined magnetic path, Diag_2 Second inclined magnetic path.

Claims

1. A magnetostrictive torque angle sensor having a shaft with a magnetostrictive portion and a magnetic pole portion arranged around the shaft, wherein the magnetic pole portion is formed in an arc shape and comprises a first magnetic pole stage and a second magnetic pole stage arranged opposite the first magnetic pole stage with an axial gap therebetween, the first magnetic pole stage has a first protruding magnetic pole that protrudes radially toward the shaft, and the second magnetic pole stage has a second protruding magnetic pole that protrudes radially toward the shaft at a position different from the first protruding magnetic pole in the circumferential direction, an excitation coil and an angle detection coil are wound around the first protruding magnetic pole, and a torque detection coil is wound around the second protruding magnetic pole, and the magnetostrictive torque angle sensor is configured so that magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole changes periodically as the shaft rotates.

2. The magnetostrictive torque angle sensor according to claim 1, wherein the magnetic resistance changes depending on whether the radial distance from the central axis of the shaft to the magnetostrictive section changes periodically in the circumferential direction, or whether the magnitude of the magnetostrictive section in the direction along the axial center changes periodically in the circumferential direction.

3. The magnetostrictive torque angle sensor as described in claim 1, wherein the mechanical central angle of the arc in the magnetic pole portion is an electrical angle of 360°, the excitation coils are arranged on the first protruding magnetic poles at four locations in the first magnetic pole stage that are spaced at an electrical angle of 90°, the angle detection coils are arranged on the first protruding magnetic poles at four locations in the first magnetic pole stage that are spaced at an electrical angle of 90°, and the torque detection coils are arranged on the second protruding magnetic poles at two locations in the second magnetic pole stage that are spaced at an electrical angle of 180°.

4. The magnetostrictive torque angle sensor as described in claim 1, wherein the mechanical central angle of the arc in the magnetic pole portion is an electrical angle of 360°, the excitation coil is disposed at at least one location of the first protruding magnetic pole, the angle detection coil is disposed at least two locations of the first protruding magnetic pole within the first magnetic pole stage, and the torque detection coil is disposed at two locations of the second protruding magnetic pole within the second magnetic pole stage, the two locations forming an electrical angle of 180°.

5. The magnetostrictive torque angle sensor according to claim 1, wherein the mechanical central angle of the arc in the magnetic pole portion is an electrical angle of 360°, the excitation coil is disposed at least on two first protruding magnetic poles in the first magnetic pole stage, forming an electrical angle of 180°, the angle detection coil is disposed at least on two first protruding magnetic poles in the first magnetic pole stage, and the torque detection coil is disposed at one second protruding magnetic pole in the second magnetic pole stage.

6. A magnetostrictive torque angle sensing system comprising: a magnetostrictive torque angle sensor according to any one of claims 1 to 4; and a processing unit that processes a torque detection signal from said torque detection coil and an angle detection signal from said angle detection coil, wherein said processing unit supplies an excitation signal to said excitation coil, detects the torque applied to said shaft from the torque detection signal from said torque detection coil, and detects the angle of said shaft from the angle detection signal from said angle detection coil.

7. A magnetostrictive torque angle sensing system comprising: a magnetostrictive torque angle sensor according to claim 5; and a processing unit for processing a torque detection signal from said torque detection coil and an angle detection signal from said angle detection coil, said processing unit supplying an excitation signal to said excitation coil, detecting the angle of said shaft from the angle detection signal from said angle detection coil, correcting the torque detection signal from said torque detection coil using the angle detection signal from said angle detection coil, and detecting the torque acting on said shaft.

8. A magnetostrictive torque angle sensor having a shaft having a magnetostrictive portion and a magnetic pole portion arranged around the shaft, wherein the magnetic pole portion is formed in an arc shape and includes a first magnetic pole stage and a second magnetic pole stage arranged opposite to the first magnetic pole stage with an axial gap therebetween, the first magnetic pole stage has a plurality of first protruding magnetic poles protruding radially toward the shaft, an excitation coil and an angle detection coil are wound around at least four poles of the plurality of first protruding magnetic poles, the at least four excitation coils are configured by alternatingly arranging first excitation coils and second excitation coils, a first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil and the second excitation coil, respectively, the second magnetic pole stage has a second protruding magnetic pole protruding radially toward the shaft at a position different from the first protruding magnetic pole in the circumferential direction, and a torque detection coil of at least one pole is wound around the second protruding magnetic pole, A magnetostrictive torque angle sensor configured such that a magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole changes periodically with rotation of the shaft.

9. The magnetostrictive torque angle sensor according to claim 8, wherein the magnetic resistance changes depending on whether the radial distance from the central axis of the shaft to the magnetostrictive section changes periodically in the circumferential direction, or whether the magnitude of the magnetostrictive section in the direction along the axis of the shaft changes periodically in the circumferential direction.

10. The magnetostrictive torque angle sensor as described in claim 8, wherein, when n is an integer equal to or greater than 2, the first magnetic pole stage has the excitation coil and the angle detection coil wound around the first protruding magnetic pole of 2n poles, and the 2n-pole excitation coil is configured such that the first excitation coil of n poles and the second excitation coil of n poles are alternately arranged in the circumferential direction, one pole at a time.

11. The magnetostrictive torque angle sensor according to claim 8, wherein the first excitation coil is supplied with the first excitation signal, and the second excitation coil is supplied with the second excitation signal, the second excitation signal having a phase difference of a certain angle from the first excitation signal.

12. The magnetostrictive torque angle sensor according to claim 8, wherein the torque detection coil is disposed in the second pole stage located midway between two adjacent first protruding poles in the circumferential direction.

13. A magnetostrictive torque angle sensing system comprising: a magnetostrictive torque angle sensor according to any one of claims 8 to 12; and a processing unit that processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil, wherein the processing unit supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively, detects the torque applied to the shaft from the torque detection signal from the torque detection coil, and detects the angle of the shaft from the angle detection signal from the angle detection coil.

14. The magnetostrictive torque angle sensing system according to claim 13, wherein the processing unit corrects the torque detection signal using the angle detection signal to detect the torque.

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