Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system

Abstract

To materialize a magnetostrictive torque angle sensor which can detect torque and angle and is easily replaceable.SOLUTION: A magnetostrictive torque angle sensor 100 comprises a shaft 10 having a magnetostrictive portion 12, and a magnetic pole portion 101 located around the shaft 10. The magnetic pole portion 101 is formed in shape of a circular arc and includes a first magnetic pole stage 101A and a second magnetic pole stage 101B located facing the first magnetic pole portion 101A while being spaced in the axial direction. The first magnetic pole stage 101A includes a first protruding magnetic pole 110 protruding in the radial direction toward the shaft 10, and the second magnetic pole stage 101B includes a second protruding magnetic pole 120 protruding in the radial direction toward the shaft 10 and located at a position different from the first protruding magnetic pole 110 in the circumferential direction. An exciting 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. Magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 is constituted in such a manner that the magnetic resistance periodically changes with the 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 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, 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 an axial gap therebetween, the first magnetic pole stage having a first protruding magnetic pole protruding radially toward the shaft, and the second magnetic pole stage having a second protruding magnetic pole protruding 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 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, the mechanical central angle of the arc in the magnetic pole portion is 360° electrical angle, 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 the present invention, the mechanical central angle of the arc in the magnetic pole portion is 360° electrical angle, 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, with the mechanical central angle of the arc in the magnetic pole portion being 360° electrical angle.

[0012] In the magnetostrictive torque angle sensor of the present invention, the mechanical central angle of the arc in the magnetic pole portion is taken as 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, where the mechanical central angle is 180° electrical angle, 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 a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil, wherein 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 pole stage, 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 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. 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. 3 is a characteristic diagram showing an output voltage characteristic obtained by processing a voltage generated in a torque detection coil during rotation of a shaft in the magnetostrictive torque angle sensor according to the first embodiment. [Figure 14] FIG. 4 is a characteristic diagram showing output voltage characteristics obtained by processing a voltage generated in an angle detection coil during rotation of a shaft in the magnetostrictive torque angle sensor according to the first embodiment. [Figure 15] FIG. 3 is a characteristic diagram showing an output voltage characteristic obtained by processing a voltage generated in a torque detection coil when torque is input in the magnetostrictive torque angle sensor according to the first embodiment. [Figure 16] FIG. 4 is a characteristic diagram showing an output voltage characteristic obtained by processing a voltage generated in an angle detection coil when torque is input in the magnetostrictive torque angle sensor according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment 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.

[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. 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 arranged opposite the first magnetic pole stage 101A with a gap in the axial direction therebetween, via a gap adjustment portion 190.

[0021] An arc is a part of a circumference. In this specification, even if the outer or inner circumference of the magnetic pole part 101 is not a part of a smooth circumference but is a 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 is treated as an "arc". The angle between the center of a circle that constitutes an arc and the two ends of the arc is defined as the central angle of the arc. In this embodiment, the central angle of the arc is sometimes called the mechanical central angle of the arc to distinguish it from the electrical angle described later. In the specific example shown in FIG. 1, the magnetic pole portion 101 is formed with a central angle of about 180°. Theoretically, the central angle of the arc is greater than 0° and smaller 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 magnetostrictive torque angle sensor 100 to be provided with magnetic poles and coils (described later), 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 preferable that the magnetic resistance of the shaft 10 periodically changes in accordance with the central angle of the arc.

[0022] 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. 1, the first protruding magnetic poles 110 include four first protruding magnetic poles 110a, 110b, 110c, and 110d that are provided at equal angular intervals. In the second pole stage 101B, a second protruding magnetic pole 120 protruding radially toward the shaft 10 is provided at a position different from the first protruding magnetic pole 110 in the circumferential direction. In the specific example shown in Fig. 1, two second protruding magnetic poles 120a and 120c are provided as the second protruding magnetic pole 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.

[0023] 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 Fig. 1 and Fig. 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 Figures 1 and 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.

[0024] 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 120a and 120c, the excitation signal, the angle detection signal, and the phase of the angle detection signal. The first protruding magnetic poles 110a-110d are arranged at intervals of 90 electrical degrees within a range of an electrical angle of 360. Note that the angular intervals of the first protruding magnetic poles 110a-110d are not strictly limited to 90 degrees and may include slight variations or errors. The second protruding magnetic pole 120a is disposed at a midpoint between the first protruding magnetic poles 110a to 110b in the circumferential direction. The second protruding magnetic pole 120c is disposed at a midpoint between the first protruding magnetic poles 110c to 110d in the circumferential direction.

[0025] 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 about 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.

[0026] The excitation coil 130 is illustrated as a specific example of four poles, excitation coils 130a to 130d. Note that the excitation coil 130 only needs to be arranged at least in two poles that form an electrical angle of 180° in the first magnetic pole stage 101A, and at the very least, it only needs to be arranged in one location in the first magnetic pole stage 101A.

[0027] The angle detection coil 150 illustrates 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.

[0028] 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 spaced apart by an electrical angle of 180° from each other, it is sufficient that the torque detection coil 140 is disposed at at least one location in the second magnetic pole stage 101B.

[0029] 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.

[0030] 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. 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 poles 120a to 120c on the shaft 10 may have a cross-sectional shape of a perfect circle. Here, 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.

[0031] 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 poles 120a-120c 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 poles 120a-120c 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.

[0032] 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 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 and 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.

[0033] 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 poles 120a-120c 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 poles 120a-120c 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.

[0034] 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 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, 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.

[0035] 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.

[0036] 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 first embodiment. The magnetostrictive torque angle sensing system 1 includes a magnetostrictive torque angle sensor 100 and a processing unit 200. Here, an excitation coil 130, a torque detection coil 140, and an angle detection coil 150 are shown in the magnetostrictive torque angle sensor 100 in relation to the processing unit 200.

[0037] 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.

[0038] 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 voltages generated in the torque detection coils 140a and 140c when the shaft 10 rotates without any torque input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 13 shows the torque detection signals generated in the torque detection coils 140a and 140c when the shaft 10 rotates without any 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 electrical angle of 360°. Therefore, a composite torque detection signal obtained by combining the torque detection signals generated in the torque detection coils 140a and 140c is in a flat state with no voltage change. As a result, the processing unit 200 outputs torque data indicating torque=0. In other words, even if the shaft 10 rotates, there is no effect on the 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 with the angle detection signal, it is possible to obtain a flat characteristic as shown in Fig. 13, and the problem can be dealt with without any adverse effects on torque detection. 13, the torque detection signal is shown as having a sine waveform, but is not limited to this. When 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, a multi-step stepped wave, etc., the torque detection signal also has a waveform of a similar shape.

[0039] Angle detection when axis 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 any torque input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 14 shows the angle detection signals generated in the angle detection coils 150a to 150d when the shaft 10 rotates without any 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 is the first angle detection phase, has one cycle of voltage change per electrical angle of 360°. The angle detection signal generated in the angle detection coils 150c and 150d (hereinafter referred to as the "second angle detection signal"), which is the second angle detection phase, has a phase difference of 90° with the first angle detection signal, and has one cycle of voltage change per electrical angle of 360°. Therefore, the processing unit 200 obtains the angle of rotation of the shaft 10 by comparing the amplitude values ​​of the first angle detection signal from the angle detection coils 150a and 150b and the second angle detection signal from the angle detection coils 150c and 150d, and outputs the angle as angle data. Note that, although the angle detection signal is shown as having a sine waveform in Fig. 14, the angle detection signal is not limited to this. When 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, a multi-step step wave, etc., the angle detection signal also has a waveform of a similar shape.

[0040] Torque detection when torque is input without rotation of shaft 10: Fig. 15 is a characteristic diagram showing characteristics of voltages generated in the torque detection coils 140a and 140c in the magnetostrictive torque angle sensor 100 according to the first embodiment when the shaft 10 is not rotating and torque is input to the shaft 10. Fig. 15 shows torque detection signals generated in the torque detection coils 140a and 140c when the shaft 10 is not rotating and torque is input. 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 according to torque is obtained from 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. Therefore, the processing unit 200 obtains the input torque to the shaft 10 based on the composite torque detection signal and outputs it as torque data.

[0041] Angle detection with torque input without rotation of axis 10: Fig. 16 is a characteristic diagram showing the characteristics of the voltages generated in the angle detection coils 150a to 150d when the shaft 10 is not rotating and torque is input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 16 shows the angle detection signals generated in the angle detection coils 150a to 150d when torque is input to the shaft 10 and the shaft 10 is not rotating. Here, 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 angle detection signal and the second angle detection signal is in a flat state with no voltage change. As a result, the processing unit 200 outputs angle data indicating angle=0. In other words, even if there is torque input to the shaft 10, there is no effect on the angle detection.

[0042] 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 calculates both the angle and the torque by performing the processes described using Figs. 13 to 16 in parallel.

[0043] In the above-described first embodiment, the excitation coils 130a-130d are wound around all of the first protruding magnetic poles 110a-110d of the first magnetic pole stage 101A, but the magnetostrictive torque angle sensor 100 is not limited to this state. That is, the excitation coil 130 needs to be arranged at least around two poles that form an electrical angle of 180° in the first magnetic pole stage 101A, and at the very least, it needs to be arranged at any one location in the first magnetic pole stage 101A.

[0044] In the above first embodiment, the angle detection coils 150a-150d are wound around all of the first protruding magnetic poles 110a-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 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.

[0045] In the above-described first embodiment, 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, but the magnetostrictive torque angle sensor 100 is not limited to this state. In other words, it is sufficient that the torque detection coil 140 is disposed at least at one location in the second magnetic pole stage 101B.

[0046] When reducing the number of excitation coils 130, torque detection coils 140, and angle detection coils 150, it is possible not to provide the first protruding magnetic poles 110 in the first magnetic pole stage 101A in a portion where there are no excitation coils 130 and no angle detection coils 150. Similarly, it is possible not to provide the second protruding magnetic poles 120 in the second magnetic pole stage 101B in a portion where there are no torque detection coils 140.

[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 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 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 first magnetic pole stage 101B protruding radially toward the shaft 10. The second magnetic pole stage 101B has a protruding magnetic pole 110, and a second protruding magnetic pole 120 that protrudes radially toward the shaft 10 at a different position in the circumferential direction 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 as the shaft 10 rotates. In this magnetostrictive torque angle sensor 100, in the same sensor, 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. 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, the mechanical central angle of the arc in the magnetic pole portion 101 is taken as 360° electrical angle, and the excitation coils 130 are arranged at four first protruding magnetic poles 110 at intervals of 90° electrical angle in the first magnetic pole stage 101A, the angle detection coils 150 are arranged at four first protruding magnetic poles 110 at intervals of 90° electrical angle in the first magnetic pole stage 101A, and the torque detection coils 140 are arranged at two second protruding magnetic poles 120 at intervals of 180° electrical angle in the second magnetic pole stage 101B. This makes it possible to detect angle and torque without interference with each other using a single sensor, and makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10.

[0050] Note (4): In the magnetostrictive torque angle sensor 100 of Supplementary Notes (1) to (3) above, the mechanical central angle of the arc in the magnetic pole portion 101 is taken as 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 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, which correspond 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.

[0051] Note (5): In the magnetostrictive torque angle sensor 100 of the above supplementary notes (1) to (3), the mechanical center 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 least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A, where the mechanical center angle is 180°, the angle detection coil 150 is disposed at least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A, and the torque detection coil 140 is disposed at one second protruding magnetic pole 120 in the second magnetic pole stage 101B. Here, 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 the torque applied to the shaft 10. As a result, even with a single sensor with a minimum configuration, the torque detection is not adversely affected in any way, and it is possible to detect the angle and torque without interference, and it becomes 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 (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 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. 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 can be facilitated.

[0053] Note(7): The magnetostrictive torque angle sensing system 1 described in the above embodiment includes the magnetostrictive torque angle sensor 100 described in the above supplementary note (5) 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 angle of the shaft 10 using the angle detection signal from the angle detection coil 150, corrects the torque detection signal from the torque detection coil 140 using the angle detection signal from the angle detection coil 150, and detects the torque applied to the shaft 10. 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. Even a single sensor with a minimum configuration can detect the angle and torque without any adverse effect on the torque detection and without interference, making it easy to replace the magnetic pole portion 101 with respect to the shaft 10. [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, 120a, 120c second protruding magnetic pole, 130, 130a to 130d excitation coil, 140, 140a, 140d 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 first protruding pole protruding radially toward the axis, 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, An excitation coil and an angle detection coil are wound around the first protruding magnetic pole, 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 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. The mechanical central angle of the arc in the magnetic pole portion is an electrical angle of 360°, The excitation coils are disposed on the first protruding magnetic poles at four locations in the first magnetic pole stage at intervals of 90 electrical degrees, The angle detection coils are disposed on the first protruding magnetic poles at four locations in the first magnetic pole stage at intervals of 90 electrical degrees, The torque detection coils are disposed on two second protruding magnetic poles at positions corresponding to an electrical angle of 180° in the second magnetic pole stage.

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

4. 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 of the first protruding magnetic poles, The angle detection coil is disposed at least in two first protruding magnetic poles in the first magnetic pole stage, The torque detection coils are disposed on two second protruding magnetic poles at positions corresponding to an electrical angle of 180° in the second magnetic pole stage.

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

5. 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 at two locations of the first protruding magnetic poles in the first magnetic pole stage, the two locations corresponding to an electrical angle of 180°. The angle detection coil is disposed at least in two first protruding magnetic poles in the first magnetic pole stage, The torque detection coil is disposed on one of the second protruding poles in the second pole stage.

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

6. A magnetostrictive torque angle sensor according to any one of claims 1 to 4, 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 an excitation signal to the excitation coil; 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 magnetostrictive torque angle sensor according to claim 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 an excitation signal to the excitation coil; Detecting an angle of the shaft based on an angle detection signal from the angle detection coil; a torque detection signal from the torque detection coil is corrected using an angle detection signal from the angle detection coil to detect a torque applied to the shaft; Magnetostrictive torque angle sensing system.

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