JP7515929B1 - Magnetostrictive torque angle sensor and magnetostrictive torque angle sensing system - Google Patents

Abstract

A torque and an angle are detected by the same sensor.
The magnetostrictive torque angle sensor 100 has a magnetostrictive shaft 10 and a magnetic pole section 101. The magnetic pole section 101 has a first magnetic pole stage 101A and a second magnetic pole stage 101B. The first magnetic pole stage 101A has a first protruding magnetic pole 110 that protrudes in the radial direction. An excitation coil 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110. The excitation coil 130 is formed by alternately winding a first excitation coil 131 and a second excitation coil 132. a first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil 131 and the second excitation coil 132, the second magnetic pole stage 101B has a second protruding magnetic pole 120 that protrudes radially at a circumferentially different position from the first protruding magnetic pole 110, a torque detection coil 140 is wound around the second protruding magnetic pole 120, and the magnetic resistance between the magnetostrictive portion 12 and the first protruding magnetic pole 110 changes as the shaft 10 rotates.
[Selected Figure] Figure 1

Description

The present invention relates to a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system, and in particular to a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that can detect torque and angle using the same sensor.

A magnetostrictive torque sensor is known that detects the torque acting on the shaft due to rotation by providing a magnetostrictive film with 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.

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 change in impedance corresponding to the torque.

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.

JP 2008-76066 A

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.

The magnetostrictive torque angle sensor according to the present invention is a magnetostrictive torque angle sensor having a shaft having a magnetostrictive portion and a magnetic pole portion arranged around the shaft, the magnetic pole portion having a first magnetic pole stage and a second magnetic pole stage arranged opposite the first magnetic pole stage with a gap in the axial direction, the first magnetic pole stage having a first protruding magnetic pole protruding radially toward the shaft, an excitation coil and an angle detection coil are wound around at least two of the first protruding magnetic poles, and the excitation coils of the at least two poles are The first and second excitation coils are arranged alternately, a first excitation signal and a second excitation signal having different phases are supplied to the first and second excitation coils, respectively, the second magnetic pole stage has a second protruding magnetic pole that protrudes radially toward the shaft at a circumferentially different position from the first protruding magnetic pole, at least one 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 with the rotation of the shaft.

The magnetostrictive torque angle sensor of this invention is configured so that 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.

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

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

In the magnetostrictive torque angle sensor of this invention, the torque detection coil is arranged in the second pole stage located midway between the first protruding poles of two adjacent poles in the circumferential direction.

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

In the magnetostrictive torque angle sensor of the present invention, the excitation coil is arranged at least on two first protruding poles that have an electrical angle of 180° in the first pole stage, the angle detection coil is arranged at least on a first protruding pole that has an electrical angle of 90° from each other in the first pole stage, and the torque detection coil is arranged on one second protruding pole in the second pole stage.

In the magnetostrictive torque angle sensor of this invention, the second magnetic pole stage further includes a second protruding magnetic pole that is not wound with a torque detection coil.

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 any two poles within the second magnetic pole stage, and a processing unit that supplies an excitation signal to the excitation coil and processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil. The processing unit supplies a first excitation signal and a second excitation signal, which are out of phase with each other, to the first excitation coil and the second excitation coil, respectively, detects the torque applied to the shaft from the torque detection signal from the torque detection coil, and detects the angle of the shaft from the angle detection signal from the angle detection coil.

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 one of the poles in the second magnetic pole stage, and a processing unit that supplies an excitation signal to the excitation coil and processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil. The processing unit supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively, detects the angle of the shaft using the angle detection signal from the angle detection coil, corrects the torque detection signal from the torque detection coil using the angle detection signal, and detects the torque applied to the shaft.

The magnetostrictive torque angle sensor of the present invention can provide a torque detection signal and an angle detection signal, making it possible to provide a magnetostrictive torque angle sensor and a magnetostrictive torque angle sensing system that can detect torque and angle using the same sensor.

1 is a perspective view showing a configuration of a magnetostrictive torque angle sensor according to a first embodiment; 2 is a cross-sectional view showing a cross section taken along line II-II in FIG. 1. 2 is a cross-sectional view showing a cross section taken along line III-III in FIG. 1. 3 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. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. FIG. 2 is a diagram showing the configuration of a shaft of the magnetostrictive torque angle sensor according to the first embodiment. 4 is a characteristic diagram showing the magnetic resistance characteristics of the magnetostrictive torque angle sensor according to the first embodiment. FIG. FIG. 1 is a configuration diagram showing a configuration of a magnetostrictive torque angle sensing system according to a first embodiment. FIG. 4 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. FIG. 4 is a characteristic diagram showing an output voltage characteristic 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. FIG. 4 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. 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.

The following describes an embodiment of the magnetostrictive torque angle sensor 100 of the present invention and a magnetostrictive torque angle sensing system 1 using the magnetostrictive torque angle sensor 100, with reference to the drawings. Note that the same parts are denoted by the same reference numerals in each drawing.

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.

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 by a torque generating portion (not shown).
The magnetic pole portion 101 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.

[Magnetic poles and various coils]
The first magnetic pole stage 101A is provided with at least two first protruding magnetic poles 110 that protrude radially toward the shaft 10. In the specific example shown in Fig. 1, four first protruding magnetic poles 110, that is, first protruding magnetic poles 110a, 110b, 110c, and 110d, are provided at equal angular intervals. As will be described later, the number of magnetic poles of the first protruding magnetic poles 110 can be changed in accordance with the number of poles of the excitation coil 130 and the angle detection coil 150.
In the second pole stage 101B, at least one second protruding magnetic pole 120 protruding radially toward the shaft 10 is provided at a circumferentially different position from the first protruding magnetic pole 110. In the specific example shown in Fig. 1, four second protruding magnetic poles 120a, 120b, 120c, and 120d are provided at equal angular intervals as the second protruding magnetic poles 120. As will be described later, the number of magnetic poles of the second protruding magnetic poles 120 can be changed in accordance with the number of poles of the torque detection coil 140.

[Regarding the first protruding magnetic pole]
At least two excitation coils 130 and an angle detection coil 150 are wound around the first protruding magnetic pole 110 .
In the specific example shown in Figures 1 and 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.

Here, the at least two-pole excitation coil 130 is configured by alternately arranging a first excitation coil 131 and a second excitation coil 132. In the specific example shown in Fig. 1 and Fig. 4, the excitation coils 130a and 130c are the first excitation coil 131, and the excitation coils 130b and 130d are the second excitation coil 132.
Here, a first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil 131 and the second excitation coil 132, respectively. The first excitation signal and the second excitation signal are realized by, for example, a sine-phase excitation signal and a cosine-phase excitation signal having a phase difference of 90°. Note that the sine-phase excitation signal and the cosine-phase excitation signal are only examples, and various periodic waveforms such as a triangular wave, a rectangular wave, and a multi-step stepped wave may be used instead of the sine wave and the cosine wave. The phase difference between the first excitation signal and the second excitation signal is not strictly limited to 90°.
Although FIGS. 1 and 4 show a specific example in which the exciting coils 130a to 130d are arranged in four poles, it is sufficient that they are arranged in at least two poles that form an electrical angle of 90° within the first magnetic pole stage 101A.
The angle detection coils 150a to 150d output the induced voltage as an angle detection signal. Note that, although the angle detection coils 150a to 150d are illustrated as being arranged in four poles, it is sufficient that they are arranged in at least two poles at the same positions as the excitation coil 130 within the first magnetic pole stage 101A.

[Regarding the second protruding magnetic pole]
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 140b is wound around the second protruding magnetic pole 120b, and a torque detection coil 140d is wound around the second protruding magnetic pole 120d at a position corresponding to an electrical angle of 180°. The torque detection coils 140b and 140d output an induced voltage as a torque detection signal.
Although the torque detection coil 140 is illustrated as specific examples of torque detection coils 140b and 140d, it is sufficient that the torque detection coil 140 has two poles located at positions that are 180° apart from each other in the second magnetic pole stage 101B. It is also possible to arrange the torque detection coil 140 at only one of the poles in the second magnetic pole stage 101B. In this case, it is desirable to arrange the torque detection coil 140 at the second magnetic pole stage located midway between the first protruding magnetic poles of two adjacent poles in the circumferential direction.

[Magnetic path]
Here, the first protruding magnetic poles 110a to 110d and the second protruding magnetic poles 120a to 120d are arranged at different circumferential positions at intervals of 90° electrical angle within a range of 360° electrical angle, with four poles in each group. Note that the intervals of 90° electrical angle are not strictly limited to 90° 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 about 45° is formed between the second protruding magnetic pole 120b, the magnetostrictive portion 12, and the first protruding magnetic pole 110b, and between the second protruding magnetic pole 120d, the magnetostrictive portion 12, and the first protruding magnetic pole 110d. Similarly, a second inclined magnetic path Diag_2 of about -45° is formed between the second protruding magnetic pole 120b, 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 110a.
In addition, the angles of 90° and 45° in the above specific examples may include slight errors or intentional changes.

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

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 to 120d 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 120d on the shaft 10 may have a cross-sectional shape of a perfect circle.

The shaft 10 is formed in one of the following ways. The magnetostrictive portion 12 as a magnetostrictive film is applied to the outer peripheral surface of the inner shaft portion 11 having the shape of FIG. 5 by coating, spraying, or the like to form the shaft 10. Alternatively, the inner shaft portion 11 is press-fitted into the magnetostrictive portion 12 as an outer cylinder having the outer shape of FIG. 5 or FIG. 6 to form the shaft 10. Alternatively, the inner shaft portion 11 and the magnetostrictive portion 12 may all be made of magnetostrictive material, and the entire shaft 10 may be formed of the magnetostrictive portion 12. Note that the same manufacturing method can be applied to the other forms of shaft 10 shown below.

In FIG. 7, the magnetostrictive portion 12 is formed by coating or spraying 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 pressed 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. Note that in FIG. 7, 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.

In FIG. 8, the magnetostrictive portion 12 formed 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 120d. 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 120d 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. 5.

In FIG. 9, a magnetostrictive portion 12 is formed on a part of the outer peripheral surface of the cylindrical inner shaft portion 11 at a position where the first protruding magnetic poles 110a-110d and the second protruding magnetic poles 120a-120d face the shaft 10, and the axial size of the magnetostrictive portion 12 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. Note that in FIG. 9, the cross section of the inner shaft portion 11 is not limited to a perfect circle, and may be configured such that the radius changes periodically in the circumferential direction as shown in FIG. 5.

In FIG. 10, the magnetostrictive portion 12 formed on a part of the outer circumferential surface of the inner shaft portion 11 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 120d, 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 120d 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. 5.

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.

[Processing of magnetostrictive torque angle sensing system 1]
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. Fig. 12 shows an excitation coil 130, a torque detection coil 140, and an angle detection coil 150 in the magnetostrictive torque angle sensor 100 in relation to the magnetostrictive torque angle sensor 100 and the processing unit 200.

The processing unit 200 supplies an excitation signal to the excitation coil 130. That is, the processing unit 200 supplies a first excitation signal and a second excitation signal as two types of excitation signals with different phases to the first excitation coil 131 (excitation coils 130a and 130c) and the second excitation coil 132 (excitation coils 130b and 130d) included in the excitation coil 130. The processing unit 200 uses two types of excitation signals with a phase difference of 90°, for example a sine-phase excitation signal and a cosine-phase excitation signal, as the two types of excitation signals with different phases.

The processing unit 200 receives torque detection signals from the torque detection coils 140, and detects the torque applied to the shaft 10 based on voltage changes as amplitude information of the torque detection signals. In the example shown in Fig. 1, the processing unit 200 receives torque detection signals from the torque detection coils 140b and 140d as the torque detection coils 140, and detects the torque applied to the shaft 10 based on voltage changes as amplitude information of the torque detection signals. The processing unit 200 outputs the detected torque to the outside as torque data.
The processing unit 200 receives an angle detection signal from the angle detection coil 150, and detects the angle of the shaft 10 based on the phase difference between the angle detection signal and a reference signal. In the example shown in Fig. 1, the processing unit 200 receives an angle detection signal from angle detection coils 150a to 150d as the angle detection coil 150, and detects the angle of the shaft 10 based on the phase difference between the angle detection signal and an excitation signal. The processing unit 200 outputs the detected angle to the outside as angle data.

[Torque detection and angle detection processing]
Hereinafter, with reference to FIGS. 13 to 16, the angle detection characteristics and torque detection characteristics when the shaft 10 rotates and when torque is input will be described in detail.

Torque detection when the shaft 10 rotates without torque input:
13 is a characteristic diagram showing output voltage characteristics obtained by processing voltages generated in the torque detection coils 140b and 140d when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Here, FIG. 13 shows the result of combining the torque detection signals generated in the torque detection coils 140b and 140d when the shaft 10 rotates without torque input.
The torque detection signals generated in the torque detection coils 140b and 140d have a phase difference of 180°, and one cycle of voltage change occurs per electrical angle of 360°. Therefore, the output voltage characteristic at the time of torque detection obtained by combining the torque detection signals generated in the torque detection coils 140b and 140d is a flat characteristic with no voltage change according to the rotation angle, as shown in FIG.
As a result, the processing unit 200 calculates the torque as 0, and outputs to the outside the torque data indicating the torque as 0. In other words, even if the shaft 10 rotates, there is no effect on the torque detection.

In the above example, the torque detection signals generated in the torque detection coils 140b and 140d are combined to obtain a flat output voltage characteristic without voltage change according to the rotation angle shown in FIG. 13. On the other hand, it is possible to arrange the torque detection coil 140 on any one of the second protruding poles 120 in the second pole stage 101B. If the torque detection coil 140 has only one pole in this way, it is not possible to obtain a flat output voltage characteristic without voltage change according to the rotation angle, and a voltage change component according to the rotation angle is output from the torque detection coil 140 even though there is no torque input. In this case, the torque detection signal from the torque detection coil 140 is corrected using the angle detection signal from the angle detection coil 150, so that it is possible to obtain a flat output voltage characteristic without voltage change according to the rotation angle shown in FIG. 13 for the torque applied to the shaft 10.

Angle detection when the shaft 10 rotates without torque input:
14 is a characteristic diagram showing output voltage characteristics obtained by processing voltages generated in the angle detection coils 150a to 150d when the shaft 10 rotates without torque input to the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 14 shows how angles are detected by processing the angle detection signals generated in the angle detection coils 150a to 150d when the shaft 10 rotates without torque input.
The processing unit 200 receives the angle detection signals from the angle detection coils 150a to 150d, and detects the angle of the shaft 10 based on the phase difference between the angle detection signals and a reference signal. The reference signals are excitation signals corresponding to the respective angle detection signals. Thus, the processing unit 200 receives the angle detection signals from the angle detection coils 150a to 150d, and detects the angle of the shaft 10 based on the phase difference θ between the angle detection signals and the excitation signal. The processing unit 200 outputs the detected angle to the outside as angle data.
The relationship between the excitation signal and the angle detection signal will be explained below using mathematical expressions.
The excitation signal is
E _R1-R3 = Ecosωt
E _R2-R4 =Esinωt
This can be expressed as:
And the angle detection signal is
E _S1-S2
=kE(sinωt・sinθ+cosωt・cosθ)
=kEcos(ωt-θ)
It becomes.
That is, the processing unit 200 can detect the angle of the shaft 10 as a waveform that is shifted by θ from the reference excitation signal cosωt.
Therefore, the output voltage characteristic during angle detection is such that the voltage changes linearly according to the rotation angle, as shown in Fig. 14. This allows the processing unit 200 to calculate the rotation angle, and output angle data indicating the rotation angle to the outside.

Torque detection when torque is input without rotation of shaft 10:
15 is a characteristic diagram showing output voltage characteristics obtained by processing the voltages generated in the torque detection coils 140b and 140d when torque is input to the shaft 10 without rotating the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 15 shows the difference between the torque detection signals generated in the torque detection coils 140b and 140d when torque is input to the shaft 10 without rotating the shaft 10.
Focusing on the torque detection signals obtained from the first inclined magnetic path Diag_1 and the second inclined magnetic path Diag_2 described in FIG. 4, the torque detection signal obtained from the first inclined magnetic path Diag_1 and the torque detection signal obtained from the second inclined magnetic path Diag_2 have different voltage change rates.
The processing unit 200 obtains an output voltage characteristic at the time of torque detection 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. The output voltage characteristic at the time of torque detection has a linear voltage change rate according to the torque, as shown in Fig. 15. In this way, the processing unit 200 obtains the input torque to the shaft 10, and outputs the obtained torque to the outside as torque data.

Angle detection when torque is input without rotation of shaft 10:
16 is a characteristic diagram showing output voltage characteristics obtained by processing voltages generated in the angle detection coils 150a to 150d when torque is input to the shaft 10 without rotating the shaft 10 in the magnetostrictive torque angle sensor 100 according to embodiment 1. Fig. 16 shows the difference between the angle detection signals generated in the angle detection coils 150a to 150d when torque is input to the shaft 10 without rotating.
Here, the angle detection signals generated in the angle detection coils 150a to 150d have the same characteristics. Therefore, the 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 of the shaft 10.

The above Figs. 13 to 16 have described the characteristics when the shaft 10 rotates without torque being input to the shaft 10, or when torque is input to the shaft 10 without the shaft 10 rotating. In reality, in an electric power steering device or a rotating shaft of a robot, a state may occur in which the shaft 10 rotates while torque is also input to the shaft 10. In such a case, the processing unit 200 can calculate the angle and torque by performing the processes described using Figs. 13 to 16 in parallel.

[Changing the number of magnetic poles]
In the above-described first embodiment, the excitation coils 130a to 130d and the angle detection coils 150a to 150d are wound around the first magnetic pole stage 101A, and the torque detection coils 140b and 140d are wound around the second magnetic pole stage 101B, but the magnetostrictive torque angle sensor 100 is not limited to this state.
The excitation coil 130 needs to be arranged at least on the two first protruding magnetic poles 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 arranged.
The angle detection coil 150 is configured by arranging two poles at positions that are at an electrical angle of 90° from each other within the first magnetic pole stage 101A, i.e., one pole of either angle detection coil 150a or 150b, and one pole of either angle detection coil 150c or 150d, for a total of two poles, on the first protruding magnetic pole 110.
The torque detection coils 140 need only be arranged at least on the two 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 angle obtained from the angle detection signal in the processing unit 200, the torque detection coil 140 can be arranged with only one pole among the torque detection coils 140a to 140d.

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 the portions 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 the portions where there are no torque detection coils 140.
On the other hand, even when the excitation coil 130, the torque detection coil 140, and the angle detection coil 150 are reduced, it is also possible not to reduce the first protruding magnetic poles 110 in the portions where the excitation coil 130 and the angle detection coil 150 are not present (not wound) from the first magnetic pole stage 101A, and similarly not to reduce the second protruding magnetic poles 120 in the portions where the torque detection coil 140 is not present (not wound) from the second magnetic pole stage 101B. In this case, the first magnetic pole stage 101A and the second magnetic pole stage 101B have the same number of protruding magnetic poles, making it possible to share components.

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° and the mechanical angle of 360° match.
In contrast, by providing eight first and second protruding magnetic poles 110 and 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 which has an angle of 30° between the first protruding magnetic poles 110 and the second protruding magnetic poles 120, 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°. Furthermore, it is possible to increase the number of poles to any number using a similar structure.

The above-mentioned number of poles can be changed as follows. When n is a positive integer of 2 or more, it is possible to provide 2n-pole first protruding magnetic poles 110 spaced apart by an electrical angle of (360/2n)° in the first magnetic pole stage 101A, and to wind the excitation coil 130 and the angle detection coil 150 around the 2n-pole first protruding magnetic poles 110. Here, the 2n-pole excitation coil 130 is configured by alternately arranging n-pole first excitation coils 131 and n-pole second excitation coils 132, one pole at a time, in the circumferential direction. That is, the first excitation coils 131 and the second excitation coils 132 are alternately arranged at intervals of an electrical angle of (360/2n)°.
This makes it possible to detect the angle and torque without interference with a single sensor using the excitation coil 130 and the angle detection coil 150 with any number of poles, and also makes it easy to replace the magnetic pole portion 101 with respect to the shaft 10. Also, it is possible to provide a first protruding magnetic pole 110 in which the first excitation coil 131 and the second excitation coil 132 are not wound more than 2n in the first magnetic pole stage 101A.

[Effects Obtained by the Embodiments]
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 has a first protruding magnetic pole 110 protruding in the radial direction toward the shaft 10, and an excitation coil 130 and an angle detection coil 150 are wound around at least two poles of the first protruding magnetic pole 110, respectively, and at least two The pole excitation coil 130 is configured by alternatingly arranging first excitation coils 131 and second excitation coils 132, and a first excitation signal and a second excitation signal of different phases are supplied to the first excitation coil 131 and the second excitation coil 132, respectively. The second magnetic pole stage 101B has a second protruding magnetic pole 120 that protrudes radially toward the shaft 10 at a circumferentially different position from the first protruding magnetic pole 110, and at least one pole of the torque detection coil 140 is wound around the second protruding magnetic pole 120, and 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, a torque detection signal can be obtained from the torque detection coil 140 and an angle detection signal can be obtained from the angle detection coil 150 using the same sensor, i.e., the same shaft 10 and magnetic pole portion 101. This makes it possible to detect both torque and angle using the same sensor.

Note (2):
In the magnetostrictive torque angle sensor 100 of the above supplementary note (1), the magnetic resistance is configured to change periodically with the rotation of the shaft 10 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 magnetostrictive portion 12 in the direction along the axis of the shaft 10 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.

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

Note (4):
In the magnetostrictive torque angle sensor 100 described in the above supplementary notes (1) to (3), a first excitation signal is supplied to a first excitation coil 131, and a second excitation signal having a phase difference of 90° from that of the first excitation signal is supplied to a second excitation coil 132. This makes it possible to detect angle and torque without interference with each other using a single sensor.

Note (5):
In the magnetostrictive torque angle sensor 100 described in Supplementary Notes (1) to (4) above, the torque detection coil 140 is disposed in the second pole stage 101B located midway between two adjacent first protruding magnetic poles 110 in the circumferential direction. This makes it possible to detect not only angle but also torque using the same shaft 10 and magnetic pole portion 101. This makes it possible to detect angle and torque without interference with each other using a single sensor.

Note (6):
In the magnetostrictive torque angle sensor 100 of the above supplementary notes (1) to (5), the excitation coil 130 is disposed at least on two first protruding magnetic poles 110 that form an electrical angle of 180° in the first magnetic pole stage 101A, the angle detection coil 150 is disposed at least on the first protruding magnetic poles 110 at positions that form an electrical angle of 90° with respect to each other in the first magnetic pole stage 101A, and the torque detection coil 140 is disposed at least on two second protruding magnetic poles 120 that form an electrical angle of 180° in the second magnetic pole stage 101B. This makes it possible to detect angle and torque without interference by the same sensor using the same shaft 10 and magnetic pole portions 101.

Note (7):
In the magnetostrictive torque angle sensor 100 of the above supplementary notes (1) to (5), the excitation coil 130 is disposed at least on the first protruding magnetic poles 110 of two poles that form an electrical angle of 180° in the first magnetic pole stage 101A, the angle detection coil 150 is disposed at least on the first protruding magnetic poles 110 of a position that forms an electrical angle of 90° with respect to each other in the first magnetic pole stage 101A, and the torque detection coil 140 is disposed on the second protruding magnetic pole 120 of one pole 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 when the torque detection coil 140 has only one pole or has 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 the torque without interference by a single sensor having a minimum configuration using the same shaft 10 and magnetic pole portion 101.

Note (8):
In the magnetostrictive torque angle sensor 100 of the above supplementary notes (1) to (7), the second magnetic pole stage 101B further includes a second protruding magnetic pole 120 that is not wound with the torque detection coil 140. In this case, the first magnetic pole stage 101A and the second magnetic pole stage 101B have the same number of protruding magnetic poles, making it possible to share components.

Note (9):
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 (6) above, and a processing unit 200 that supplies an excitation signal to the excitation coil 130 and processes a torque detection signal from the torque detection coil 140 and an angle detection signal from the angle detection coil 150. The processing unit 200 supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil 131 and the second excitation coil 132, respectively, detects the torque applied to the shaft 10 from the torque detection signal from the torque detection coil 140, and detects the angle of the shaft 10 from the angle detection signal from the angle detection coil 150. This makes it possible to realize the magnetostrictive torque angle sensor 100 and the magnetostrictive torque angle sensing system 1 that are capable of detecting torque and angle using the same sensor.

Note (10):
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 (7), and a processing unit 200 that supplies an excitation signal to the excitation coil 130 and processes a torque detection signal from the torque detection coil 140 and an angle detection signal from the angle detection coil 150. The processing unit 200 supplies a first excitation signal and a second excitation signal having different phases to the first excitation coil 131 and the second excitation coil 132, respectively, detects the 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, and detects the torque applied to the shaft 10. Here, by correcting the torque detection signal using the angle detection signal, torque detection is not adversely affected even when the torque detection coil 140 has only one pole or multiple poles that are unbalanced in the circumferential direction. This makes it possible to realize the magnetostrictive torque angle sensor 100 and the magnetostrictive torque angle sensing system 1 that are capable of detecting both torque and angle using the same sensor.

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, 131 first excitation coil, 132 second excitation coil, 140, 140b, 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 (10)

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,
An excitation coil and an angle detection coil are wound around at least two of the first protruding magnetic poles,
The at least two-pole excitation coil is configured by alternately arranging a first excitation coil and a second excitation coil,
a first excitation signal and a second excitation signal having different phases are supplied to the first excitation coil and the second excitation coil, respectively;
the second pole stage has a second protruding pole protruding radially toward the axis at a position different in the circumferential direction from the first protruding pole,
A torque detection coil having at least one pole is wound around the second protruding magnetic pole,
The magnetic resistance between the magnetostrictive portion and the first protruding magnetic pole is configured to change periodically with rotation of the shaft.
Magnetostrictive torque angle sensor. 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. When n is an integer of 2 or more,
In the first magnetic pole stage, the excitation coil and the angle detection coil are wound around the first protruding magnetic poles having 2n poles,
The 2n-pole excitation coil is configured by alternately arranging the n-pole first excitation coil and the n-pole second excitation coil in a circumferential direction, one pole at a time.
2. The magnetostrictive torque angle sensor according to claim 1. The first excitation signal is supplied to the first excitation coil,
The second excitation coil is supplied with the second excitation signal, the second excitation signal having a phase different from that of the first excitation signal by a certain angle.
2. The magnetostrictive torque angle sensor according to claim 1. the torque detection coil is disposed in the second pole stage located midway between the first protruding poles of two adjacent poles in the circumferential direction;
2. The magnetostrictive torque angle sensor according to claim 1. The excitation coil is disposed at least at the first protruding poles of two poles that form an electrical angle of 180° in the first pole stage,
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 at least in the second protruding magnetic poles of two poles that form an electrical angle of 180° in the second magnetic pole stage.
2. The magnetostrictive torque angle sensor according to claim 1. The excitation coil is disposed at least at the first protruding poles of two poles that form an electrical angle of 180° in the first pole stage,
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. the second pole stage further includes the second protruding pole that is not wound with the torque detection coil;
2. The magnetostrictive torque angle sensor according to claim 1. A magnetostrictive torque angle sensor according to any one of claims 1 to 6,
a processing unit that supplies an excitation signal to the excitation coil and processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil,
The processing unit includes:
supplying a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively;
Detecting a torque applied to the shaft based on a torque detection signal from the torque detection coil;
detecting an angle of the shaft based on an angle detection signal from the angle detection coil;
Magnetostrictive torque angle sensing system. The magnetostrictive torque angle sensor according to claim 7 ;
a processing unit that supplies an excitation signal to the excitation coil and processes a torque detection signal from the torque detection coil and an angle detection signal from the angle detection coil,
The processing unit includes:
supplying a first excitation signal and a second excitation signal having different phases to the first excitation coil and the second excitation coil, respectively;
Detecting 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 the angle detection signal to detect a torque applied to the shaft;
Magnetostrictive torque angle sensing system.