Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system

Abstract

To materialize a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system each of which can detect torque and angle by one and the same sensor.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 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 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 to periodically change 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 size of the entire 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 the torque and angle using one sensor without physically providing two sensors. 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. [Means for solving the problem]

[0007] 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 comprising 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.

[0008] In the magnetostrictive torque angle sensor of the present invention, the magnetic resistance is configured to change 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 magnitude of the magnetostrictive portion in the direction along the axis changes periodically in the circumferential direction.

[0009] In the magnetostrictive torque angle sensor of the present invention, the excitation coil is arranged at least at two first protruding magnetic poles in the first magnetic pole stage, where the two poles form an electrical angle of 180°, the angle detection coil is arranged at least at the first protruding magnetic poles in the first magnetic pole stage, where the two poles form an electrical angle of 90° with respect to each other, and the torque detection coil is arranged at least at two second protruding magnetic poles in the second magnetic pole stage, where the two poles form an electrical angle of 180°.

[0010] In the magnetostrictive torque angle sensor of the present invention, the excitation coil is arranged at least at two first protruding magnetic poles in the first magnetic pole stage that form an electrical angle of 180°, the angle detection coil is arranged at least at a first protruding magnetic pole in the first magnetic pole stage that forms an electrical angle of 90° with respect to each other, and the torque detection coil is arranged at one second protruding magnetic pole in the second magnetic pole stage.

[0011] 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 in at least 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, and the processing unit 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.

[0012] 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 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

[0013] In the magnetostrictive torque angle sensor according to the present invention, a torque detection signal and an angle detection signal can be obtained, so that it is possible 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. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a configuration of a magnetostrictive torque angle sensor according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] 2 is an explanatory diagram showing a first protruding magnetic pole and a second protruding magnetic pole of the magnetostrictive torque angle sensor according to the first embodiment in a developed state. 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]4 is a characteristic diagram showing characteristics of a voltage generated in a torque detection coil during rotation of a shaft in the magnetostrictive torque angle sensor according to the first embodiment. FIG. [Figure 14] 4 is a characteristic diagram showing characteristics of a voltage generated in an angle detection coil during rotation of a shaft in the magnetostrictive torque angle sensor according to the first embodiment. FIG. [Figure 15] FIG. 4 is a characteristic diagram showing characteristics of 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 characteristics of 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

[0015] 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. 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. [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 a first protruding magnetic pole 110 and a second protruding magnetic pole 120 of the magnetostrictive torque angle sensor 100 according to embodiment 1 in a developed state.

[0016] The magnetostrictive torque angle sensor 100 mainly comprises a shaft 10 and a magnetic pole portion 101. The shaft 10 has a magnetostrictive portion 12 on its outer circumferential surface. The shaft 10 is held by a bearing or the like (not shown) and configured to be rotatable relative to the magnetic pole portion 101. The shaft 10 rotates together with a test object (not shown) or receives torque. The magnetic pole portion 101 is disposed around the shaft 10. The magnetic pole portion 101 comprises a first magnetic pole stage 101A and a second magnetic pole stage 101B disposed opposite the first magnetic pole stage 101A at an axial distance via a distance adjustment portion 190.

[0017] 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, second protruding magnetic poles 120 protruding radially toward the shaft 10 are provided at circumferential positions different from those of the first protruding magnetic poles 110. In the specific example shown in Fig. 1, four second protruding magnetic poles 120 are provided, namely, second protruding magnetic poles 120a, 120b, 120c, and 120d.

[0018] 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 Fig. 1 and Fig. 4, a torque detection coil 140a is wound around the second protruding magnetic pole 120a, a torque detection coil 140b is wound around the second protruding magnetic pole 120b, a torque detection coil 140c is wound around the second protruding magnetic pole 120c, and a torque detection coil 140d is wound around the second protruding magnetic pole 120d.

[0019] Here, the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120a-120d are arranged at intervals of 90 electrical degrees within a range of 360 electrical degrees, with four poles in each set at different positions in the circumferential direction, as shown in Fig. 4. Note that the intervals of 90 electrical degrees are not strictly limited to 90 degrees, and may include slight variations or errors. Horizontal magnetic paths H 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, between the first protruding magnetic pole 110c, the magnetostrictive portion 12, and the first protruding magnetic pole 110d, and between the first protruding magnetic pole 110d, the magnetostrictive portion 12, and the first protruding magnetic pole 110a. A first inclined magnetic path Diag_1 of approximately 45° is formed between the second protruding magnetic pole 120a, the magnetostrictive portion 12, and the first protruding magnetic pole 110a, between the second protruding magnetic pole 120b, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, between the second protruding magnetic pole 120c, the magnetostrictive portion 12, and the first protruding magnetic pole 110c, and between the second protruding magnetic pole 120d, the magnetostrictive portion 12, and the first protruding magnetic pole 110d. A second inclined magnetic path Diag_2 of approximately -45° is formed between the second protruding magnetic pole 120a, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, between the second protruding magnetic pole 120b, the magnetostrictive portion 12, and the first protruding magnetic pole 110c, between the second protruding magnetic pole 120c, the magnetostrictive portion 12, and the first protruding magnetic pole 110d, and between the second protruding magnetic pole 120d, the magnetostrictive portion 12, and the first protruding magnetic pole 110a.

[0020] Although four specific examples of excitation coils 130a to 130d are shown in the figure, it is sufficient that the excitation coil 130 is disposed at at least two locations that form an electrical angle of 180° within the first magnetic pole stage 101A. Although four specific examples of angle detection coils 150a to 150d are shown in the figure, it is sufficient that the angle detection coils 150 are disposed at at least two positions that are spaced apart by an electrical angle of 90° from each other within the first magnetic pole stage 101A. Although four specific examples of torque detection coils 140a to 140d are shown in the figure, it is sufficient that the torque detection coils 140 are placed at at least two locations within the second magnetic pole stage 101B that are spaced apart by an electrical angle of 180° from each other, or at any one location within the second magnetic pole stage 101B.

[0021] [Magnetic resistance characteristics] Next, 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.

[0022] In Fig. 5, the shaft 10 includes an inner shaft portion 11 and a magnetostrictive portion 12 provided on the outer periphery of the inner shaft portion 11, and is configured so that the radius of the shaft 10 changes periodically in the circumferential direction. As a result, the first magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic poles 110a-110d and the second magnetic resistance between the magnetostrictive portion 12 and the second protruding magnetic poles 120a-120d change periodically with the rotation of the shaft 10, as shown in Fig. 11. Note that the shaft 10 only needs to have the cross-sectional shape and magnetostrictive portion 12 as shown in Fig. 5 at the positions where the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120a-120d face the shaft 10, and the other portions may be configured so as to be perfectly circular and not to have the magnetostrictive portion 12. Of the first and second magnetic resistances, it is desirable that the first magnetic resistance required for angle detection changes periodically with the rotation of the shaft 10. For this reason, as shown in Fig. 6, it is sufficient that only the magnetostrictive region 12a 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.

[0023] 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 having the same shape into magnetostrictive portion 12 as an outer cylinder having the shape in Fig. 5 or 6. Alternatively, inner shaft portion 11 and magnetostrictive portion 12 may be made of a magnetostrictive material, and the entire shaft 10 may be formed of magnetostrictive portion 12.

[0024] 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-120d 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-120d change periodically with the rotation of the shaft 10, as shown in FIG. 11. The cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured so that the radius changes periodically in the circumferential direction as shown in FIG. 5.

[0025] 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. The cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius changes periodically in the circumferential direction as shown in FIG.

[0026] In FIG. 9, 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-120d 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 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-120d change periodically with the rotation of the shaft 10, as shown in FIG. 11. The cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured so that the radius changes periodically in the circumferential direction as shown in FIG. 5.

[0027] 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 is constant. The cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured so that the radius changes periodically in the circumferential direction as shown in FIG. 5.

[0028] The cross-sectional shape of shaft 10 shown in FIG. 5, the shape of magnetostrictive portion 12 shown in FIGS. 6 to 10, and the magnetoresistance change rate shown in FIG. 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 shaft 10, the shape of magnetostrictive portion 12 shown in FIGS. 6 to 10, and the magnetic resistance change rate shown in FIG. 11 may be determined based on various periodic shapes such as a triangular wave, a rectangular wave, or a multi-step stepped wave.

[0029] [Magnetostrictive torque angle sensing system 1 processing] The magnetostrictive torque angle sensing system 1 will now be described 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.

[0030] 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 based on a comparison of the amplitudes of the plurality of angle detection signals, and outputs angle data.

[0031] 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.

[0032] 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 to 140d 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 to 140d when the shaft 10 rotates without any torque input. The torque detection signals generated in the torque detection coils 140a to 140d have a phase difference of 90°, 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 to 140d 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. 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.

[0033] 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 signals generated in the angle detection coils 150a and 150c (hereinafter referred to as "first angle detection signal group") have a voltage change of one cycle per electrical angle of 360°. The angle detection signals (hereinafter, "second angle detection signal group") generated in the angle detection coils 150b and 150d have a phase difference of 90° with the first angle detection signal group, and one cycle of voltage change occurs per electrical angle of 360°. Therefore, the processing unit 200 obtains the angle during rotation of the shaft 10 by comparing the amplitude values ​​of the first angle detection signal group and the second angle detection signal group, and outputs the angle data. 14, the angle 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 angle detection signal also has a waveform of a similar shape.

[0034] Torque detection when torque is input without rotation of shaft 10: Fig. 15 is a characteristic diagram showing the characteristics of the voltages generated in the torque detection coils 140a to 140d in the magnetostrictive torque angle sensor 100 according to embodiment 1 when the shaft 10 is not rotating and torque is input to the shaft 10. Fig. 15 shows the torque detection signals generated in the torque detection coils 140a to 140d when torque is input with the shaft 10 not rotating. Focusing on the torque detection signals obtained in the first inclined magnetic path Diag_1 and the second inclined magnetic path Diag_2 described in FIG. 4, the torque detection signal obtained in the first inclined magnetic path Diag_1 and the torque detection signal obtained in 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 torque detection signal obtained in the first inclined magnetic path Diag_1 and the torque detection signal obtained in 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.

[0035] 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 angle detection signals generated in the angle detection coils 150a to 150d have the same characteristics. Therefore, a composite angle detection signal obtained by calculating the difference between the angle detection signals generated in the angle detection coils 150a to 150d 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 a torque input to the shaft 10, there is no effect on the angle detection.

[0036] 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.

[0037] [Changing magnetic poles and coils] In the above-described first embodiment, the excitation coils 130a-130d and 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, and the torque detection coils 140a-140d are wound around all of the second protruding magnetic poles 120a-120d of the second magnetic pole stage 101B, but the magnetostrictive torque angle sensor 100 is not limited to this state.

[0038] The excitation coil 130 needs to be disposed at least at two locations on the first protruding magnetic pole 110 that form an electrical angle of 180° within the first magnetic pole stage 101A, and excitation coils 130a and 130c, or excitation coils 130b and 130d may be disposed. Two angle detection coils 150 should be arranged on the first protruding magnetic pole 110 at positions that are 90° apart from each other in the first magnetic pole stage 101A, i.e., either one of angle detection coils 150a or 150b, and either one of angle detection coils 150c or 150d. The torque detection coils 140 need to be arranged at least at two locations of the second protruding magnetic poles 120 that form an electrical angle of 180° within the second magnetic pole stage 101B, and torque detection coils 140a and 140c, or torque detection coils 140b and 140d may be arranged. When the torque detection signal is corrected by the processing unit 200 based on the angle obtained from the angle detection signal, only one of the torque detection coils 140a to 140d may be arranged as the torque detection coil 140. In other words, by correcting the torque detection signal based on the angle obtained from the angle detection signal, 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.

[0039] 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 torque detection coils 140. 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 angle detection coils 150.

[0040] In the above description, the first protruding magnetic poles 110a to 110d and the second protruding magnetic poles 120a to 120d form four poles, so that the electrical angle of 360° matches the mechanical angle of 360°. In contrast, by providing eight first protruding magnetic poles 110 and eight second protruding magnetic poles 120 at 45° intervals, an electrical angle of 360° can be accommodated within a mechanical angle of 180°. In this case, the electrical angle of 180° corresponds to a mechanical angle of 90°, and the electrical angle of 90° corresponds to a mechanical angle of 45°. Furthermore, by providing 12 poles, each of the first protruding magnetic poles 110 and the second protruding magnetic poles 120 at 30° intervals, an electrical angle of 360° can be accommodated in a mechanical angle of 120°. In this case, an electrical angle of 180° corresponds to a mechanical angle of 60°, and an electrical angle of 90° corresponds to a mechanical angle of 30°. It is also possible to increase the number of poles using a similar structure. In the above description, the angle values ​​such as 90°, 180°, 360°, etc. are not completely free of errors or variations, but allow for a certain degree of error or variation within the range in which the effects of the invention can be achieved.

[0041] [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 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 includes a first protruding magnetic pole protruding radially toward the shaft 10. The first protruding magnetic pole 120 is wound around the magnetostrictive portion 12 and the second protruding magnetic pole 110. The second magnetic pole stage 101B has a second protruding magnetic pole 120 that protrudes radially toward the shaft 10 at a position different from the first protruding magnetic pole 110 in the circumferential direction, and an excitation coil 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110, and a torque detection coil 140 is wound around the second protruding magnetic pole 120, so that the magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 changes periodically with the rotation of the shaft 10. In this magnetostrictive torque angle sensor 100, a torque detection signal is obtained from the torque detection coil 140, and an angle detection signal is obtained from the angle detection coil 150, all in the same sensor.

[0042] Note (2): In the magnetostrictive torque angle sensor 100 of the above supplementary note (1), the magnetic resistance is configured to change 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. This makes it possible to detect not only torque but also angle using the same shaft 10 and magnetic pole portion 101.

[0043] Note (3): In the magnetostrictive torque angle sensor 100 of Supplementary Notes (1) and (2) above, the excitation coil 130 is disposed at least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A, where the excitation coil 130 is disposed at two first protruding magnetic poles 110 at positions where the mutual electrical angle is 90° in the first magnetic pole stage 101A, and the torque detection coil 140 is disposed at least at two second protruding magnetic poles 120 at positions where the mutual electrical angle is 180° 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.

[0044] Note (4): In the magnetostrictive torque angle sensor 100 of the above supplementary notes (1) and (2), the excitation coil 130 is disposed at least at two first protruding magnetic poles 110 in the first magnetic pole stage 101A, where the excitation coil 130 is disposed at an electrical angle of 180°, the angle detection coil 150 is disposed at least at a first protruding magnetic pole 110 in the first magnetic pole stage 101A, where the angle detection coil 150 is disposed at an electrical angle of 90°, and the torque detection coil 140 is disposed at least at one second protruding magnetic pole 120 in the second magnetic pole stage 101B. In this case, the torque detection signal from the torque detection coil 140 can be corrected using the angle detection signal from the angle detection coil 150 to detect the torque applied to the shaft 10. Here, by correcting the torque detection signal using the angle detection signal, even if the torque detection coil 140 has only one pole or multiple poles that are unbalanced in the circumferential direction, the torque detection is not adversely affected at all. This makes it possible to detect the angle and torque using a single sensor with a minimum configuration.

[0045] Note (5): 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 (3) 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 detects the torque applied to the shaft from the torque detection signal from the torque detection coil 140, and detects the angle of the shaft from the angle detection signal from the angle detection coil 150. This makes it possible to realize the magnetostrictive torque angle sensing system 1 that uses the magnetostrictive torque angle sensor 100 that can detect both torque and angle using the same sensor.

[0046] Note (6): 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 (4) and a processing unit 200 that processes the torque detection signal from the torque detection coil 140 and the angle detection signal from the angle detection coil 150. The processing unit 200 detects the angle of the shaft from 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. Here, by correcting the torque detection signal using the angle detection signal, even if the torque detection coil 140 has only one pole or multiple poles at circumferentially unbalanced positions, the torque detection is not adversely affected at all. Therefore, it is possible to realize the magnetostrictive torque angle sensing system 1 using the magnetostrictive torque angle sensor 100 that can detect torque and angle using the same sensor. [Explanation of symbols]

[0047] 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 to 120d second protruding magnetic pole, 130, 130a to 130d excitation coil, 140, 140a to 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 A first pole stage; and a second pole stage disposed opposite the first pole stage with an axial gap therebetween, 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 configured to change 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 magnitude of the magnetic resistance in the direction along the axis of the magnetostrictive portion changes periodically in the circumferential direction.

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

3. 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 coils are disposed at least at the first protruding magnetic poles at positions that are spaced apart from each other by an electrical angle of 90° within the first magnetic pole stage, The torque detection coil is disposed on at least two of the second protruding magnetic poles in the second magnetic pole stage, the two second protruding magnetic poles being spaced apart by an electrical angle of 180°.

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

4. 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 coils are disposed at least at the first protruding magnetic poles at positions that are spaced apart from each other by an electrical angle of 90° within 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.

5. A magnetostrictive torque angle sensor according to any one of claims 1 to 3, 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: 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.

6. The magnetostrictive torque angle sensor according to claim 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: 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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