Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system

Abstract

To materialize an easily replaceable magnetostrictive torque angle sensor.SOLUTION: A magnetostrictive torque angle sensor 100 comprises a shaft 10 having a magnetostrictive characteristic, and an arc-shaped magnetic pole portion 101 formed in shape of a circular arc. The magnetic pole portion 101 includes a first magnetic pole stage 101A and a second magnetic pole stage 101B. The first magnetic pole stage 101A includes a plurality of first protruding magnetic poles 110. An exciting coil 130 and an angle detection coil 150 are wound around the first protruding magnetic poles 110, the exciting coil 130 is composed of a first exciting oil 131 and a second exciting coil 132 that are alternately arranged, and a first exciting signal and a second exciting signal differing in phase are supplied to the first exciting oil 131 and the second exciting coil 132. The second magnetic pole stage 101B includes a second protruding magnetic pole 120 at a position different from the first protruding magnetic pole 110 in the radial direction. A torque detection coil 140 is wound around the second protruding magnetic pole 120. Magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 changes with rotation of the shaft 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[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 capable of detecting torque and angle using the same sensor. [Background technology]

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

[0003] When torque is applied to a shaft provided with a magnetostrictive film, distortion occurs in the magnetostrictive film on the shaft surface, and the magnetic permeability of the magnetostrictive film changes due to the Villari effect. The impedance of the windings of the magnetostrictive torque sensor changes in response to this change in magnetic permeability of the magnetostrictive film. As a result, the magnetostrictive torque sensor can obtain a detection signal corresponding to the torque acting on the shaft from the impedance change corresponding to the torque.

[0004] In order to detect not only the torque applied to a shaft but also the angle of the shaft, it is necessary to provide an angle sensor on the same shaft in addition to the torque sensor. This type of magnetostrictive torque angle sensor is described in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-76066 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the torque and angle sensor described in Patent Document 1, it is necessary to physically provide two sensors. As a result, there is a problem that the overall size of the sensor becomes large and the cost of two sensors is required. In addition, the probability of occurrence of a malfunction may increase with the increase in the number of parts. For this reason, it is desirable to be able to detect torque and angle with one sensor by sharing the stator without physically providing two sensors.

[0007] Conventional magnetostrictive sensors are constructed by arranging annular magnetic pole parts around a shaft, which has the problem that it is not easy to replace the magnetic pole parts while leaving the shaft in place. The present invention has been made to solve the above-mentioned problems, and has an object to provide a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that are capable of detecting torque and angle using the same sensor and whose magnetic pole portion is easily replaceable. [Means for solving the problem]

[0008] The magnetostrictive torque angle sensor according to the present invention is a magnetostrictive torque angle sensor having a shaft having a magnetostrictive portion and a magnetic pole portion arranged around the shaft, the magnetic pole portion 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 towards the shaft, an excitation coil and an angle detection coil being wound around at least four of the plurality of first protruding magnetic poles, The four-pole excitation coil is configured by alternatingly 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 circumferentially different position from the first protruding magnetic pole, and at least one pole of a torque detection coil is wound around the second protruding magnetic pole. 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 of 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 the present invention, where n is an integer equal to or greater than 2, in the first magnetic pole stage, an excitation coil and an angle detection coil are each wound around a first protruding magnetic pole of 2n poles, and the 2n-pole excitation coil is configured by alternating n-pole first excitation coils and n-pole second excitation coils, one pole at a time, in the circumferential direction.

[0011] In the magnetostrictive torque angle sensor according to the present invention, a first excitation signal is supplied to a first excitation coil, and a second excitation signal, the phase of which differs from that of the first excitation signal by a certain angle, is supplied to a second excitation coil.

[0012] 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.

[0013] The magnetostrictive torque angle sensing system of the present invention comprises the above-mentioned magnetostrictive torque angle sensor, 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 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] In the magnetostrictive torque angle sensing system according to the present invention, the processing unit corrects the torque detection signal based on the angle detection signal to detect the torque. Effect of the Invention

[0015] In the magnetostrictive torque angle sensor of the present invention, arc-shaped magnetic pole portions are arranged around an axis, a torque detection signal is obtained from a torque detection coil, and an angle detection signal is obtained from an angle detection coil, so that it is 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 in which the magnetic pole portions are easily replaceable. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a configuration of a magnetostrictive torque angle sensor according to a first embodiment. [Diagram 2] 2 is a cross-sectional view taken along line II-II in FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 2 is an explanatory diagram showing the arrangement of first and second protruding magnetic poles of the magnetostrictive torque angle sensor according to the first embodiment, developed onto a plane. FIG. [Diagram 5] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 6] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 8] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 9] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 10] FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 11] FIG. 3 is a characteristic diagram showing the magnetic resistance characteristics of the magnetostrictive torque angle sensor according to the first embodiment. [Figure 12] FIG. 1 is a configuration diagram showing a configuration of a magnetostrictive torque angle sensing system according to a first embodiment. [Figure 13] FIG. 4 is a characteristic diagram showing characteristics of a voltage obtained by processing a torque detection signal during rotation of a shaft in the magnetostrictive torque angle sensing system according to the first embodiment. [Figure 14] FIG. 4 is a characteristic diagram showing characteristics of a voltage obtained by processing an angle detection signal during rotation of a shaft in the magnetostrictive torque angle sensing system according to the first embodiment. [Figure 15] FIG. 4 is a characteristic diagram showing characteristics of a voltage obtained by processing a torque detection signal when torque is input in the magnetostrictive torque angle sensing system according to the first embodiment. [Figure 16] FIG. 4 is a characteristic diagram showing characteristics of a voltage obtained by processing an angle detection signal when torque is input in the magnetostrictive torque angle sensing system according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of a magnetostrictive torque angle sensor 100 according to the present invention and a magnetostrictive torque angle sensing system 1 using the magnetostrictive torque angle sensor 100 will be described with reference to the drawings. In addition, the same parts are denoted by the same reference numerals in each drawing.

[0018] Embodiment 1 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. FIG. [Configuration of magnetostrictive torque angle sensor 100] Fig. 1 is a perspective view showing the configuration of a magnetostrictive torque angle sensor 100 according to embodiment 1. 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 embodiment 1 developed on a plane.

[0019] 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 supported 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 a torque is applied to the shaft 10.

[0020] 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 to face the first magnetic pole stage 101A with a gap therebetween in the axial direction via a gap adjustment portion 190.

[0021] An arc is a part of a circumference. The angle between the two ends of an arc and the center of a circle that includes the arc is the central angle of the arc. In this embodiment, the central angle of an arc is sometimes called the mechanical central angle of the arc to distinguish it from an electrical angle, which will be described later. In addition, 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", "F", ">", "V", "L", "]", "K" or "]", or if the end of the arc is extended such as "U" or "J", it will also be treated as being a circular arc.

[0022] 1, the magnetic pole portion 101 is formed with a central angle of a circular arc of approximately 180°. Theoretically, the central angle of the circular arc is greater than 0° and smaller than 360°. In reality, the central angle of the arc is preferably equal to or larger than a first central angle (e.g., about 30°) that satisfies a first condition that allows the provision of magnetic poles and coils, described below, 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 portions 101 to be easily attached to and detached from the shaft 10. It is also preferable that the magnetic resistance of the shaft 10 changes periodically in accordance with the central angle of the arc.

[0023] 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, 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.

[0024] In the second pole stage 101B, at least one second protruding magnetic pole 120 protruding radially toward the shaft 10 is provided at a position different from the first protruding magnetic poles 110 (110a, 110b, 110c, and 110d) in the circumferential direction. In the specific example shown in FIG. 1, one second protruding magnetic pole 120 is provided at a position corresponding to the middle of the first protruding magnetic poles 110b and 110c in the circumferential direction. The position of the second protruding magnetic pole 120 may be a position corresponding to the middle of the first protruding magnetic poles 110a and 110b in the circumferential direction, or a position corresponding to the middle of the first protruding magnetic poles 110c and 110d in the circumferential direction. The second protruding magnetic pole 120 may be not only one pole but also two or more poles.

[0025] At least four excitation coils 130 and angle detection coils 150 are wound around each of the first protruding magnetic poles 110. The excitation coils 130 and angle detection coils 150 each have four poles. In the specific example shown in Figures 1 and 4, first protruding magnetic poles 110a, 110b, 110c, and 110d are provided as multiple first protruding magnetic poles 110, 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.

[0026] The at least four-pole excitation coil 130 is configured by alternately arranging first excitation coils 131 and second excitation coils 132. In the specific example shown in FIG. 1 and FIG. 4, the excitation coils 130a and 130c are the first excitation coils 131, and the excitation coils 130b and 130d are the second excitation coils 132. Here, a first excitation signal and a second excitation signal having different phases 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 by, for example, 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 only examples, and various periodic waveforms such as a triangular wave, a rectangular wave, and 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 strictly limited to 90°.

[0027] 4, the mechanical central angle of the arc in the magnetic pole portion 101 is treated as an electrical angle of 360°. The electrical angle is used for the arrangement of the first protruding magnetic poles 110a to 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, the phase of the excitation signal, the angle detection signal, and the angle detection signal. 4, the first protruding magnetic poles 110a-110d are arranged at intervals of 90 electrical degrees within a range of 360 electrical degrees. The second protruding magnetic pole 120 is arranged at a midpoint between the first protruding magnetic poles 110b-110c in the circumferential direction. Note that the angular intervals of the first protruding magnetic poles 110a-110d are not limited to strictly 90 degrees and may include some variation or error.

[0028] As shown in FIG. 4, the first protruding magnetic poles 110a to 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 between the second protruding magnetic pole 120, the magnetostrictive portion 12, and the first protruding magnetic pole 110b in a direction of about 45°. The second inclined magnetic path Diag_2 is formed between the second protruding magnetic pole 120, the magnetostrictive portion 12, and the first protruding magnetic pole 110c in a direction of about -45°.

[0029] In the specific example shown in FIGS. 1 and 4, four-pole excitation coils 130a to 130d and angle detection coils 150a to 150d are wound around first protruding magnetic poles 110a to 110d arranged at intervals of 90 electrical degrees within a range of 360 electrical degrees. In the first magnetic pole stage 101A, the four first protruding magnetic poles 110 can be provided at angular intervals narrower than an electrical angle of 90°. Specifically, the four first protruding magnetic poles 110 can be provided at intervals of about an electrical angle of 80° to 85°, which is narrower than the electrical angle of 90°.

[0030] [Magnetic resistance characteristics] Next, the configuration of the shaft 10 and its magnetic resistance characteristics will be described with reference to Fig. 5 to Fig. 11. Fig. 5 to Fig. 10 are configuration diagrams showing the configuration of the shaft 10 of the magnetostrictive torque angle sensor 100 according to the first embodiment. Fig. 11 is a characteristic diagram showing the magnetic resistance characteristics of the magnetostrictive torque angle sensor 100 according to the first embodiment.

[0031] 5, shaft 10 includes an inner shaft portion 11 and a magnetostrictive portion 12 provided on the outer periphery of inner shaft portion 11, and is configured so that the radius of shaft 10 changes periodically in the circumferential direction. As a result, the first magnetic resistance between magnetostrictive portion 12 and first protruding magnetic poles 110a to 110d and the second magnetic resistance between magnetostrictive portion 12 and second protruding magnetic pole 120 change periodically with rotation of shaft 10, as shown in FIG. Of the first and second magnetic resistances, it is desirable that the first magnetic resistance required for angle detection periodically changes with the rotation of the shaft 10. For this reason, as shown in Fig. 6, it is sufficient that only the magnetostrictive region 12a facing the first protruding magnetic poles 110a to 110d on the shaft 10 has the cross-sectional shape shown in Fig. 5, and the magnetostrictive region 12b facing the second protruding magnetic pole 120 on the shaft 10 may have a cross-sectional shape close to a perfect circle.

[0032] Shaft 10 is formed in any 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 in Fig. 5 by coating, spraying, or the like. Alternatively, shaft 10 is formed by press-fitting inner shaft portion 11 into magnetostrictive portion 12 as an outer cylinder portion having the outer shape in Fig. 5 or Fig. 6. Alternatively, inner shaft portion 11 and magnetostrictive portion 12 may all be made of magnetostrictive material, and the entire shaft 10 may be formed of magnetostrictive portion 12. Note that a similar manufacturing method can be applied to other forms of shaft 10 shown below.

[0033] In Fig. 7, the magnetostrictive portion 12 is formed by coating, spraying, or the like on a part of the outer peripheral surface of the cylindrical inner shaft portion 11, where the first protruding magnetic poles 110a-110d and the second protruding magnetic pole 120 face the shaft 10. Alternatively, the inner shaft portion 11 is press-fitted into the magnetostrictive portion 12 as an outer cylinder portion to form the shaft 10. Here, the magnetostrictive portion 12 is formed so that the size in the axial direction 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-110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic pole 120 change periodically with the rotation of the shaft 10, as shown in Fig. 11. In FIG. 7, 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.

[0034] In FIG. 8, the magnetostrictive portion 12 formed by coating or spraying on a part 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 pole 120. The magnetostrictive region 12a is formed so that the size in the axial direction changes periodically in the circumferential direction. On the other hand, the magnetostrictive region 12b is formed so that the size in the axial direction 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 pole 120 does not change with the rotation of the shaft 10 and is 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.

[0035] 9, a magnetostrictive portion 12 is provided by coating, spraying, or the like at a portion of the outer circumferential surface of the cylindrical inner shaft portion 11, where the first protruding magnetic poles 110a-110d and the second protruding magnetic pole 120 face the shaft 10, and the magnetostrictive portion 12 has an axial size that changes periodically in the circumferential direction and 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-110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic pole 120 change periodically with the rotation of the shaft 10, as shown in FIG. 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 changes periodically in the circumferential direction as in FIG.

[0036] In FIG. 10, the magnetostrictive portion 12 formed on a part of the outer circumferential surface of the inner shaft portion 11 by coating, spraying, or the like so as to protrude from the inner shaft portion 11 has a magnetostrictive region 12a and a magnetostrictive region 12b. Here, the magnetostrictive region 12a faces the first protruding magnetic poles 110a to 110d, and is formed so that its axial size changes periodically in the circumferential direction. The magnetostrictive region 12b faces the second protruding magnetic pole 120, 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 pole 120 does not change with the rotation of the shaft 10, but 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 in FIG.

[0037] 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 to 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.

[0038] [Magnetostrictive torque angle sensing system 1 processing] The magnetostrictive torque angle sensing system 1 will be described below with reference to Fig. 12. Fig. 12 is a configuration diagram showing the configuration of the magnetostrictive torque angle sensing system 1 according to the embodiment 1. The magnetostrictive torque angle sensing system 1 includes a magnetostrictive torque angle sensor 100 and a processing unit 200. 12, the excitation coils 130 (130a to 130d), the torque detection coil 140, and the angle detection coils 150 (150a to 150d) in the magnetostrictive torque angle sensor 100 are shown in relation to the magnetostrictive torque angle sensor 100 and the processing unit 200.

[0039] The processing unit 200 supplies an excitation signal to the excitation coil 130. The processing unit 200 supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil 131 and the second excitation coil 132 included in the excitation coil 130, respectively. The processing unit 200 receives angle detection signals from the angle detection coils 150 (150a to 150d), detects the angle of the shaft 10, and outputs angle data. The processing unit 200 receives torque detection signals from the torque detection coils 140, detects the torque applied to the shaft 10 from a voltage change in the torque detection signal, and outputs torque data.

[0040] Hereinafter, with reference to Figs. 13 to 16, the angle detection signal and the torque detection signal when the shaft 10 rotates and when torque is input will be described in detail. Torque detection when shaft 10 rotates without torque input: FIG. 13 is a characteristic diagram showing the characteristics of the voltage obtained by processing the torque detection signal when the shaft 10 rotates without any torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to the first embodiment. Specifically, FIG. 13 shows the characteristics obtained in the magnetostrictive torque angle sensing system 1 of embodiment 1 by correcting the torque detection signal when the shaft 10 rotates without any torque input to the shaft 10 using the angle detection signal in the processing unit 200. Here, when the shaft 10 rotates without torque input, the processing unit 200 outputs torque data indicating torque=0. That is, even if the torque detection coil 140 has only one pole or multiple poles at circumferentially unbalanced positions, the rotation of the shaft 10 does not adversely affect the torque detection. When the torque detection coil 140 has multiple poles at circumferentially balanced positions, the processing unit 200 can output torque data indicating torque=0 without correcting the torque detection signal by the angle detection signal.

[0041] Angle detection when axis 10 rotates without torque input: FIG. 14 is a characteristic diagram showing the characteristics of the voltage obtained by processing the angle detection signal when the shaft 10 rotates without any torque input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to the first embodiment. Specifically, FIG. 14 shows the 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 of embodiment 1. 14, there is a proportional relationship between the phase shift between the angle detection signal and the excitation signal and the rotation angle of the shaft 10. Therefore, the processing unit 200 creates a table of phase shifts and rotation angles in advance, obtains the phase shift between the angle detection signal and the excitation signal, and applies the phase shift to the table to obtain the angle during rotation of the shaft 10, and outputs it as angle data.

[0042] Torque detection when torque is input without rotation of shaft 10: FIG. 15 is a characteristic diagram showing the characteristics of the voltage obtained by processing the torque detection signal when torque is input to the shaft 10 without rotating in the magnetostrictive torque angle sensing system 1 according to the first embodiment. Specifically, FIG. 15 shows the voltage characteristics obtained by processing the torque detection signal in the processing unit 200 when the shaft 10 is not rotating and torque is input to the shaft 10 in the magnetostrictive torque angle sensing system 1 of embodiment 1. Regarding the torque detection signals obtained by 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 by the first inclined magnetic path Diag_1 and the second torque detection signal obtained by the second inclined magnetic path Diag_2 have different voltage change rates. Therefore, a composite torque detection signal having a linear voltage change rate according to torque is obtained by the difference between the first torque detection signal obtained by the first inclined magnetic path Diag_1 and the second torque detection signal obtained by the second inclined magnetic 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 it as torque data.

[0043] Angle detection with torque input without rotation of axis 10: FIG. 16 is a characteristic diagram showing the characteristics of the voltage obtained by processing the angle detection signal when the shaft 10 is not rotating and a torque is input to the shaft 10 in the magnetostrictive torque angle sensing system 1 according to the first embodiment. Specifically, FIG. 16 shows the 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 is not rotating but a torque is input to the shaft 10 in the magnetostrictive torque angle sensing system 1 of embodiment 1. As shown in Fig. 16, regardless of the torque input, the phase shift between the angle detection signal and the excitation signal is 0, so the processing unit 200 uses the table explained in Fig. 14, applies phase shift = 0 to the table, and outputs angle data indicating a rotation angle = 0. In other words, even if there is a torque input to the shaft 10, there is no effect on the angle detection.

[0044] 13 to 16 above 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 state may occur 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. 13 to 16 in parallel.

[0045] [Change number of poles] In the above-mentioned first embodiment, the four-pole excitation coils 130a-130d and the four-pole angle detection coils 150a-150d are wound around the four first protruding magnetic poles 110a-110d of the first magnetic pole stage 101A, but the present invention is not limited to this state. That is, the number of poles of the excitation coil 130 and the angle detection coil 150 can be increased without being limited to the specific examples of Figs. 1 and 4.

[0046] When the mechanical central angle of the arc in the magnetic pole portion 101 is an electrical angle of 360° and n is a positive integer of 2 or more, it is possible to provide 2n first protruding magnetic poles 110 at intervals of an electrical angle of (360 / 2n)° in the first magnetic pole stage 101A, and to wind the excitation coil 130 and the angle detection coil 150 around the 2n first protruding magnetic poles 110. In this case, the first excitation coil 131 and the second excitation coil 132 are alternately arranged at intervals of an electrical angle of (360 / 2n)°. Note that, in the first magnetic pole stage 101A, it is possible to provide the 2n first protruding magnetic poles 110 at angular intervals narrower than the electrical angle of (360 / 2n)°. Specifically, when n=4, it is possible to provide 8 first protruding magnetic poles 110 at intervals of about 40°, which is narrower than the electrical angle of (360 / 8)°=45°. This makes it possible to use an excitation coil 130 and an angle detection coil 150 with any number of poles 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. Also, it is possible to provide the first protruding magnetic pole 110 in the first magnetic pole stage 101A, in which the first excitation coil 131 and the second excitation coil 132 are not wound more than 2n.

[0047] [Effects obtained by the embodiment] The above embodiments and their effects are listed below as supplementary notes. Note (1): The magnetostrictive torque angle sensor 100 described in the above 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. An excitation coil 130 and an angle detection coil 150 are wound around at least four poles of the plurality of first protruding magnetic poles 110. The excitation coil 130 of at least four poles is configured by alternately arranging a first excitation coil 131 and a second excitation coil 132. A first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil 131 and the second excitation coil 132, respectively. The second magnetic pole stage 101B has a second protruding magnetic pole 120 that protrudes radially toward the shaft 10 at a circumferentially different position from the first protruding magnetic pole 110, and at least one torque detection coil 140 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 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 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.

[0048] Note (2): In the magnetostrictive torque angle sensor 100 of the above supplementary note (1), 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 the magnitude of the direction along the axis of the magnetostrictive portion 12 changes periodically in the circumferential direction. Therefore, it is possible to detect not only torque but also angle using the same shaft 10 and magnetic pole portion 101.

[0049] Note (3): In the magnetostrictive torque angle sensor 100 of Supplementary Notes (1) and (2) above, where n is an integer equal to or greater than 2, in the first magnetic pole stage 101A, an excitation coil 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110 with 2n poles, and the 2n-pole excitation coil 130 is configured by alternating n-pole first excitation coils 131 and n-pole second excitation coils 132 in the circumferential direction. This makes it possible to detect angle and torque without interference with a single sensor using excitation coils 130 and angle detection coils 150 with any number of poles, and makes it easy to replace the magnetic pole section 101 with respect to the shaft 10.

[0050] Note (4): In the magnetostrictive torque angle sensor 100 described in Supplementary Notes (1) to (3) above, a first excitation signal is supplied to the first excitation coil 131, and a second excitation signal having a phase difference of 90° from 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.

[0051] Note (5): In the magnetostrictive torque angle sensor 100 described in Supplementary Notes (1) to (4) above, the torque detection coil 140 is disposed in the second magnetic pole stage 101B 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 portion 101. 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.

[0052] Note(6): The magnetostrictive torque angle sensing system 1 described in the above embodiment includes the magnetostrictive torque angle sensor 100 described in any one of Supplementary Notes (1) to (5) 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 a first excitation signal and a second excitation signal having different phases to the first excitation coil 131 and the second excitation coil 132, respectively, detects the torque applied to the shaft 10 from the torque detection signal from the torque detection coil 140, and detects the angle of the shaft 10 from the angle detection signal from the angle detection coil 150. This makes it possible to realize the magnetostrictive torque angle sensor 100 and the magnetostrictive torque angle sensing system 1 that are easily replaceable and can detect torque and angle using the same sensor.

[0053] Note(7): In the magnetostrictive torque angle sensing system 1 of Supplementary Note (6) above, the processing unit 200 corrects the torque detection signal using the angle detection signal to detect torque. Here, even if the torque detection coil 140 has only one pole or multiple poles that are circumferentially unbalanced, the above correction prevents the rotation of the shaft 10 from adversely affecting the torque detection. 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 capable of detecting torque and angle using the same sensor. [Explanation of symbols]

[0054] 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 second protruding magnetic pole, 130, 130a to 130d excitation coil, 131 first excitation coil, 132 second excitation coil, 140 torque detection coil, 150, 150a to 150d angle detection coil, 190 spacing adjustment portion, 200 processing portion, 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 having a magnetostrictive portion and a magnetic pole portion disposed around the shaft, The magnetic pole portion is formed in an arc shape and includes a first magnetic pole stage and a second magnetic pole stage disposed opposite the first magnetic pole stage with a gap in the axial direction, The first pole stage has a plurality of first protruding poles protruding radially toward the axis, 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-pole excitation coil is configured by alternately 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 pole stage has a second protruding pole protruding radially toward the axis at a position different from the first protruding pole in the circumferential direction, A torque detection coil having at least one pole is wound around the second protruding magnetic pole, The magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole is configured to change periodically with rotation of the shaft. Magnetostrictive torque angle sensor.

2. The magnetic resistance is changed 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 of the shaft changes periodically in the circumferential direction.

2. The magnetostrictive torque angle sensor according to claim 1.

3. When n is an integer of 2 or more, In the first magnetic pole stage, the excitation coil and the angle detection coil are wound around the first protruding magnetic poles having 2n poles, The 2n-pole excitation coil is configured by alternately arranging the n-pole first excitation coil and the n-pole second excitation coil in a circumferential direction, one pole at a time.

2. The magnetostrictive torque angle sensor according to claim 1.

4. The first excitation signal is supplied to the first excitation coil, The second excitation coil is supplied with the second excitation signal, the second excitation signal having a phase different from that of the first excitation signal by a certain angle.

2. The magnetostrictive torque angle sensor according to claim 1.

5. 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; 2. The magnetostrictive torque angle sensor according to claim 1.

6. A magnetostrictive torque angle sensor according to any one of claims 1 to 5, 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 includes: supplying a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively; Detecting a torque applied to the shaft based on a torque detection signal from the torque detection coil; detecting an angle of the shaft based on an angle detection signal from the angle detection coil; Magnetostrictive torque angle sensing system.

7. The processing unit corrects the torque detection signal based on the angle detection signal and detects the torque.

7. The magnetostrictive torque angle sensing system according to claim 6.

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