Magnetostrictive torque sensor

Abstract

To provide a magnetostrictive torque sensor with which it is possible to improve detection accuracy even when there is a dispersion in the resistive components of a detection coil.SOLUTION: Provided is a torque sensor that detects torque transmitted by a magnetostrictive material 2 having magnetostrictive characteristic, said torque sensor comprising: a sensor unit 10 having a pair of first and third detection coils 31, 33 that have first linear sections 31a, 33a inclined a prescribed angle to the axial direction of the magnetostrictive material 2 and that are disposed so as to be electromagnetically coupled to each other, and a second and a fourth detection coil 32, 34 that have second linear sections 32a, 34a inclined a prescribed angle to the axial direction of the magnetostrictive material 2 in a direction opposite the first linear sections 31a, 33a and that are disposed so as to be electromagnetically coupled to each other; a drive unit 8 that applies an alternating-current drive voltage to the first and second detection coils 31, 32; and a voltage measurement unit 9 that measures the voltage generated by electromagnetic coupling to the third and fourth detection coils 33, 34.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to a magnetostrictive torque sensor. [Background technology]

[0002] Conventionally, magnetostrictive torque sensors are known that use a magnetostrictive material having magnetostrictive properties in which the permeability changes when torque (rotational torque) is applied, and detect the torque applied to the magnetostrictive material by detecting the change in the permeability of the magnetostrictive material when torque is applied as a change in the inductance of a detection coil.

[0003] Conventional magnetostrictive torque sensors have a sensor unit in which four detection coils are connected in a bridge configuration, and they detect the torque applied to a shaft with magnetostrictive properties based on the change in impedance of each detection coil due to the application of torque (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-160088 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, detection coils contain a resistive component, and this resistive component varies. In particular, when the detection coil is constructed using a wiring pattern formed on a circuit board, some degree of error occurs in the thickness and width of the wiring pattern, making it unavoidable that variations in the resistive component of the detection coil will occur. When variations in the resistive component of the detection coil occur, a phenomenon called offset occurs, where an output is generated even when no torque is applied. Furthermore, this offset due to variations in the resistive component changes significantly with temperature, which may lead to a decrease in detection accuracy.

[0006] Therefore, an object of the present invention is to provide a magnetostrictive torque sensor capable of improving detection accuracy even when there is variation in the resistance component of the detection coil. **Means for Solving the Problems**

[0007] The present invention is a torque sensor for detecting torque transmitted by a magnetostrictive material having magnetostrictive characteristics, and aims to solve the above problems. The torque sensor includes a pair of first and third detection coils having first straight portions inclined at a predetermined angle with respect to the axial direction of the magnetostrictive material and provided so as to be electromagnetically coupled to each other, and second and fourth detection coils having second straight portions inclined at the predetermined angle in a direction opposite to the first straight portion with respect to the axial direction of the magnetostrictive material and provided so as to be electromagnetically coupled to each other. A sensor unit, a drive unit that applies an alternating drive voltage to the first detection coil and the second detection coil, and a voltage measurement unit that measures a voltage generated by electromagnetic coupling in the third detection coil and the fourth detection coil. A magnetostrictive torque sensor is provided. **Effects of the Invention**

[0008] According to the present invention, it is possible to provide a magnetostrictive torque sensor capable of improving detection accuracy even when there is variation in the resistance component of the detection coil. **Brief Description of the Drawings**

[0009] [Figure 1] It is a perspective view showing the appearance of a magnetostrictive torque sensor according to an embodiment of the present invention. [Figure 2] (a) is a perspective view in which the resin mold part is omitted in FIG. 1, and (b) is a cross-sectional view showing the laminated structure of the flexible substrate and the magnetic ring. [Figure 3] It is a diagram showing an example of a wiring pattern formed on each wiring layer of the flexible substrate. [Figure 4] It is a circuit diagram showing the circuit configuration of the sensor unit. **Embodiments for Carrying Out the Invention**

[0010] [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0011] FIG. 1 is a perspective view showing the appearance of a magnetostrictive torque sensor according to the present embodiment. FIG. 2(a) is a perspective view in which the resin mold part is omitted in FIG. 1, and FIG. 2(b) is a cross-sectional view showing the laminated structure of the flexible substrate and the magnetic ring. FIG. 3 is a diagram showing an example of a wiring pattern formed on each wiring layer of the flexible substrate.

[0012] (Magnetostrictive material 2) As shown in FIGS. 1 to 3, a magnetostrictive torque sensor (hereinafter simply referred to as a torque sensor) 1 is a sensor that detects the torque (rotational torque) applied to the magnetostrictive material 2, and is attached around the magnetostrictive material 2.

[0013] The magnetostrictive material 2 is a columnar member to which torque is applied in the circumferential direction. The magnetostrictive material 2 in the torque sensor 1 is, for example, a shaft used for torque transmission in a vehicle's power train system or a shaft used for torque transmission in a vehicle's engine. As the magnetostrictive material 2, for example, a material obtained by subjecting a base material made of chromium steel containing chromium such as chromium steel, chromium molybdenum steel, or nickel chromium molybdenum steel to carburizing quenching and tempering treatment and then performing shot peening can be used.

[0014] (Sensor unit 10) The torque sensor 1 includes a sensor unit 10 provided so as to cover the periphery of the magnetostrictive material 2. The sensor unit 10 has a detection coil 3 provided around the magnetostrictive material 2 and a magnetic ring (magnetic body ring, back yoke) 4 provided so as to cover the periphery of the detection coil 3. In the present embodiment, it has four detection coils 31 to 34 from the first to the fourth.

[0015] As shown in Figures 1 and 2(a), the sensor unit 10 includes a cylindrical bobbin 5 arranged coaxially and spaced apart from the magnetostrictive material 2, a flexible substrate 6 wound around the outer surface of the bobbin 5, and a resin molded part 7. In this embodiment, the detection coil 3 is composed of a wiring pattern (wiring layer 60, described later) formed on the flexible substrate 6. The bobbin 5 is made of a non-magnetic material such as resin, and a flange portion 51 projecting radially outward is integrally formed at one end in its axial direction. The magnetic ring 4 is provided so as to cover the periphery of the flexible substrate 6.

[0016] (Resin molded part 7) As shown in Figure 1, the resin molded part 7 is for protecting the flexible substrate 6 and the magnetic ring 4, and is formed by molding resin to cover the bobbin 5, the flexible substrate 6, and the magnetic ring 4. The resin molded part 7 integrally has a main body part 71 that covers the bobbin 5, the flexible substrate 6, and the magnetic ring 4, and a flange part 72 formed to protrude outward from the main body part 71. The main body part 71 has a through hole 71a for passing the magnetostrictive material 2 through. The flange part 72 has a retaining hole 74 that passes through the flange part 72 and holds a short cylindrical color 73 made of metal. The flange part 72 is fixed to a surrounding member (a member that does not rotate with the rotation of the magnetostrictive material 2) using bolts or the like.

[0017] (Flexible circuit board 6) As shown in Figure 2(b), the flexible substrate 6 has four wiring layers 60: a first wiring layer 61, a second wiring layer 62, a third wiring layer 63, and a fourth wiring layer 64. However, the number of wiring layers 60 is not limited to these; it can be two or more layers.

[0018] The first wiring layer 61 is formed on the surface of the first base resin layer 65a, which is made of polyimide, and the back surface of the first base resin layer 65a is bonded and fixed to the second wiring layer 62 via an adhesive layer 66b. A first coverlay layer 67a made of polyimide is provided on the surface of the first wiring layer 61 via the adhesive layer 66a and is insulated. Double-sided tape 68a is attached to the surface of the first coverlay layer 67a, and the flexible substrate 6 is bonded and fixed to the bobbin 5 via this double-sided tape 68a.

[0019] The second wiring layer 62 is formed on the surface of the second base resin layer 65b, which is made of polyimide, and the third wiring layer 63 is formed on the back surface of the second base resin layer 65b.

[0020] The fourth wiring layer 64 is formed on the back surface of the third base resin layer 65c, which is made of polyimide, and the surface of the third base resin layer 65c is bonded and fixed to the third wiring layer 63 via an adhesive layer 66c. A second coverlay layer 67b made of polyimide is provided on the surface of the fourth wiring layer 64 via an adhesive layer 66d and is insulated. Double-sided tape 68b is attached to the second coverlay layer 67b, and the flexible substrate 6 and the magnetic ring 4 are bonded and fixed via this double-sided tape 68b.

[0021] The second and third wiring layers 62 and 63, which form the inner layers of the flexible substrate 6, are made of rolled copper foil. The first and fourth wiring layers 61 and 64, which form the outer layers of the flexible substrate 6, are made of electrolytic copper foil that has been copper-plated. As will be described in detail later, in the torque sensor 1, it is necessary to form vias (through holes) in the flexible substrate 6, so the outer layers, the first and fourth wiring layers 61 and 64, are plated.

[0022] Figure 3 shows an example of a wiring pattern formed on each wiring layer 60 of the flexible substrate 6. In Figure 3, the wiring pattern of each wiring layer 60 is schematically shown when the flexible substrate 6 is unfolded into a flat surface.

[0023] As shown in Figure 3, the first to fourth detection coils 31 to 34 are formed in the wiring layer 60 of the flexible substrate 6. The first and third detection coils 31 and 33 have first straight sections 31a and 33a inclined at a predetermined angle with respect to the axial direction of the magnetostrictive material 2, while the second and fourth detection coils 32 and 34 have second straight sections 32a and 34a inclined at a predetermined angle in the opposite direction to the first straight sections 31a and 33a with respect to the axial direction of the magnetostrictive material 2.

[0024] In the torque sensor 1, the change in magnetic permeability when torque is applied to the magnetostrictive material 2 is greatest in the direction of ±45 degrees from the axial direction. Therefore, by forming the first linear sections 31a and 33a to be inclined at +45 degrees from the axial direction and the second linear sections 32a and 34a to be inclined at -45 degrees from the axial direction, the detection sensitivity can be improved.

[0025] In this torque sensor 1, the wiring patterns of the wiring layer 60 forming the first detection coil 31 and the wiring layer 60 forming the fourth detection coil 34 are partially swapped, so that the first and fourth detection coils 31 and 34 are formed across two wiring layers 60 (first and second wiring layers 61 and 62). Similarly, the wiring patterns of the wiring layer 60 forming the second detection coil 32 and the wiring layer 60 forming the third detection coil 33 are partially swapped, so that the second and third detection coils 32 and 33 are formed across two wiring layers 60 (third and fourth wiring layers 63 and 64). The wiring layers 60 are electrically connected via vias.

[0026] By forming each detection coil 3 across two wiring layers 60, it becomes possible to suppress the influence of differences in the characteristics of the two wiring layers 60. As a result, it becomes possible to suppress measurement errors caused by differences in the characteristics between the wiring layers 60 and improve measurement accuracy.

[0027] In this embodiment, the wiring patterns formed on the first wiring layer 61 and the third wiring layer 63, and on the second wiring layer 62 and the fourth wiring layer 64 are substantially the same. Furthermore, the currents flowing through the wiring patterns formed on the first wiring layer 61 and the third wiring layer 63, and on the second wiring layer 62 and the fourth wiring layer 64 are made to flow in the same direction. In Figure 3, the direction of the current is indicated by white arrows. Also in Figure 3, the input electrodes of the first to fourth detection coils 31 to 34 are indicated by the symbols 31b, 32b, 33b, and 34b, and the output electrodes are indicated by the symbols 31c, 32c, 33c, and 34c. In Figure 3, the symbols a to y and A to Y are for convenience to represent the connection relationship via vias, and the same symbols indicate that they are electrically connected via vias. Note that the wiring patterns of each wiring layer 60 shown in Figure 3 are merely examples, and the specific structure of the wiring patterns is not limited to these.

[0028] In this embodiment, the sensor unit 10 is configured such that the first detection coil 31 and the third detection coil 33 overlap in the radial direction of the magnetostrictive material 2 and are electromagnetically coupled to each other. Similarly, the second detection coil 32 and the fourth detection coil 34 are configured such that they overlap in the radial direction of the magnetostrictive material 2 and are electromagnetically coupled to each other.

[0029] (Circuit configuration of sensor unit 10) Figure 4 is a circuit diagram showing the circuit configuration of the sensor unit 10. As shown in Figure 4, the torque sensor 1 includes a drive unit 8 that applies an AC drive voltage to the first detection coil 31 and the second detection coil 32, and a voltage measuring unit 9 that measures the voltage generated by electromagnetic coupling between the third detection coil 33 and the fourth detection coil 34. In Figure 4, the first to fourth detection coils 31 to 34 are represented as L1 to L4.

[0030] In this embodiment, the first detection coil 31 and the second detection coil 32 are connected in series, and the third detection coil 33 and the fourth detection coil 34 are connected in series. Here, the third detection coil 33 and the fourth detection coil 34 are connected in series such that the directions of the voltages generated by electromagnetic coupling are opposite.

[0031] The drive unit 8 is configured to apply an alternating drive voltage to the first detection coil 31 and the second detection coil 32 connected in series. As the drive unit 8, an oscillator capable of outputting an alternating drive voltage with a constant frequency may be used.

[0032] The voltage measurement unit is configured to measure the overall voltage of the third detection coil 33 and the fourth detection coil 34 connected in series. As the voltage measurement unit 9, one with a high input impedance is preferably used, and it is desirable to make the current hardly flow through the third and fourth detection coils 33 and 34. In this embodiment, a lock-in amplifier is used as the voltage measurement unit 9.

[0033] Let the mutual inductance between the first and third detection coils 31 and 33 be M 31 and the mutual inductance between the second and fourth detection coils 32 and 34 be M 42 and let the current flowing through the first and third detection coils 31 and 33 be i a . When the frequency of the drive voltage is f, the voltages V3 and V4 generated in the third and fourth detection coils 33 and 34 by electromagnetic coupling are represented by the following equations (1) and (2). Although the details will be described later, in this embodiment, the sensor unit 10 is configured such that the directions of the voltages V3 and V4 generated in the third and fourth detection coils 33 and 34 are different, and the positive and negative signs of the mutual inductances M 31 , M 42 are different. V3 = 2πf × M 31 × i a ···(1) V4 = 2πf × M 42 × i a ···(2)

[0034] The voltage measurement unit 9 measures the sum of these voltages V3 and V4, which is V (=V3+V4). In this embodiment, since the voltage measurement unit 9 has a high input impedance, almost no current flows through the third and fourth detection coils 33 and 34. Therefore, the voltage V detected by the voltage measurement unit 9 is not affected by the resistance component of the third and fourth detection coils 33 and 34.

[0035] And the mutual inductance M in equations (1) and (2) above. 31 M 42 This varies according to the torque applied to the magnetostrictive material 2. Mutual inductance M between the first and third detection coils 31 and 33 31 The magnetic flux can be divided into a component due to magnetic flux that does not pass through the magnetostrictive material 2 and a component due to magnetic flux that passes through the magnetostrictive material 2. Of these, the component due to magnetic flux that passes through the magnetostrictive material 2 is known to be inversely proportional to the magnetic resistance of the path of magnetic flux passing through the magnetostrictive material 2, that is, proportional to the permeability of the path of magnetic flux. In other words, mutual inductance M 31 Of these, the component due to the magnetic flux passing through the magnetostrictive material 2 is proportional to the permeability of the magnetostrictive material 2 in the direction inclined at 45 degrees, which serves as the path for the magnetic flux.

[0036] The permeability of the magnetostrictive material 2 in a direction inclined at 45 degrees with respect to its axial direction is u + If the torque applied to the magnetostrictive material 2 is T, then the permeability is μ. + This can be approximated as shown in equation (3) below. μ + =μ0+Δμ=μ0+C×T ···(3) However, μ0: Permeability when no torque is applied. Δμ: Change in magnetic permeability when torque is applied. C:Constant If Δμ (=C×T) in equation (3) is sufficiently small, then the mutual inductance M 31 Approximating this, it can be expressed by the following equation (4). M 31 =M C +A×T ···(4) However, M C : Constant term independent of permeability change due to torque A: First-order coefficient of torque relative to mutual inductance

[0037] Similarly, the mutual inductance M between the second and fourth detection coils 32 and 34 42 This can be expressed by equation (5) below. The minus sign on the right side means that the voltage generated in the fourth detection coil 34 is in the opposite direction to that of the third detection coil 33. M 42 =-(M C -A×T) ···(5) However, M C : Constant term independent of permeability change due to torque A: First-order coefficient of torque relative to mutual inductance

[0038] Substituting equations (4) and (5) into equations (1) and (2) above, the voltage V measured by the voltage measuring unit 9 is expressed by equation (6) below. V = 2πf × i a ×(M 31 +M 42 ) = 2πf × i a ×(2×A×T) ···(6) From equation (6), the voltage V measured by the voltage measuring unit 9 is proportional to the torque T. Therefore, by measuring the voltage V, the torque T applied to the magnetostrictive material 2 can be detected. In this embodiment, when no torque is applied to the magnetostrictive material 2, the voltage V is zero, and the sign of the voltage V changes depending on the direction in which the torque is applied.

[0039] Note that in equations (4) and (5) above, the mutual inductance M is 31 M 42 In this example, the constant A was assumed to be the same, but if there is a difference in this constant A, the voltage V when no torque is applied to the magnetostrictive material 2 will not be zero. Therefore, the mutual inductance M 31 M 42 It is more desirable to configure the sensor unit 10 so that the constant A is the same.

[0040] (Operation and Effects of the Embodiment) As described above, the magnetostrictive torque sensor 1 according to this embodiment includes a sensor unit 10 having a pair of first and third detection coils 31 and 33 that have first linear sections 31a and 33a inclined at a predetermined angle with respect to the axial direction of the magnetostrictive material 2 and are arranged to be electromagnetically coupled to each other, and second and fourth detection coils 32 and 34 that have second linear sections 32a and 34a inclined at a predetermined angle in the opposite direction to the first linear sections 31a and 33a with respect to the axial direction of the magnetostrictive material 2 and are arranged to be electromagnetically coupled to each other, a drive unit 8 that applies an AC drive voltage to the first detection coil 31 and the second detection coil 32, and a voltage measuring unit 9 that measures the voltage generated by electromagnetic coupling between the third detection coil 33 and the fourth detection coil 34.

[0041] By using a voltage measuring unit 9 with a sufficiently high input impedance, the current flowing through the third and fourth detection coils 33 and 34 can be made extremely small, enabling torque detection (detection of voltage V corresponding to torque) without being affected by the resistance components of the third and fourth detection coils 33 and 34, which have large manufacturing variations. As a result, fluctuations in the resistance component due to temperature changes can be ignored, and torque can be detected with high accuracy. In other words, according to this embodiment, even if there are variations in the resistance components of the detection coils 31 to 34, it is possible to reduce temperature fluctuations and improve detection accuracy. This embodiment is particularly effective when the detection coils 31 to 34 are configured with wiring patterns that are prone to variations in width and thickness.

[0042] (modified version) In the above embodiment, a case in which a lock-in amplifier is used as the voltage measurement unit 9 was described. However, the voltage measurement unit 9 is not limited to this, and any device that has a sufficiently high input impedance to suppress the current to the extent that the resistance component of the third and fourth detection coils 33 and 34 can be ignored is acceptable.

[0043] Furthermore, in the above embodiment, the case in which the third detection coil 33 and the fourth detection coil 34 are connected in series such that the direction of the voltage generated by electromagnetic coupling is opposite, was described. However, the invention is not limited to this, and the direction of the voltage generated by electromagnetic coupling in the third and fourth detection coils 33 and 34 may be the same. In this case, the torque applied to the magnetostrictive material 2 is determined based on the change in voltage V from the state in which no torque is applied. However, in this case, since voltage V is always output even when no torque is applied, it is more preferable to have the direction of the voltage generated by electromagnetic coupling in the third and fourth detection coils 33 and 34 be opposite so that the voltage V is zero (or approximately zero) when no torque is applied.

[0044] Furthermore, in the above embodiment, an AC drive voltage was applied to the first and second detection coils 31 and 32 connected in series, but this is not limited to this, and it is sufficient if a constant drive voltage can be applied to each of the first and second detection coils 31 and 32. For example, the system may be configured so that a drive voltage from the drive unit 8 is applied to each of the first and second detection coils 31 and 32, and it is not essential that the first and second detection coils 31 and 32 are connected in series.

[0045] Furthermore, in the above embodiment, the total voltage V of the third detection coil 33 and the fourth detection coil 34 connected in series was measured by the voltage measuring unit 9. However, the voltages V3 and V4 generated in the third and fourth detection coils 33 and 34 may be measured individually, and the voltage V may be calculated. Therefore, it is not essential that the third and fourth detection coils 33 and 34 are connected in series.

[0046] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals and other symbols in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0047] [1] A torque sensor for detecting torque transmitted by a magnetostrictive material (2) having magnetostrictive properties, comprising: a sensor unit (10) having a pair of first and third detection coils (31, 33) having first linear portions (31a, 33a) inclined at a predetermined angle with respect to the axial direction of the magnetostrictive material (2) and arranged to be electromagnetically coupled to each other; and second and fourth detection coils (32, 34) having second linear portions (32a, 34a) inclined at a predetermined angle in the direction opposite to the first linear portions (31a, 33a) with respect to the axial direction of the magnetostrictive material (2) and arranged to be electromagnetically coupled to each other; a drive unit (8) for applying an AC drive voltage to the first detection coil (31) and the second detection coil (32); and a voltage measuring unit (9) for measuring the voltage generated by electromagnetic coupling between the third detection coil (33) and the fourth detection coil (34), wherein the magnetostrictive torque sensor (1) is a magnetostrictive torque sensor (1).

[0048] [2] The magnetostrictive torque sensor (1) described in [1], wherein the sensor unit (10) has the first detection coil (31) and the second detection coil (32) connected in series, and the third detection coil (33) and the fourth detection coil (34) connected in series, the drive unit (8) is configured to apply an AC drive voltage to the first detection coil (31) and the second detection coil (32) connected in series, and the voltage measuring unit (9) measures the total voltage of the third detection coil (33) and the fourth detection coil (34) connected in series.

[0049] [3] The magnetostrictive torque sensor (1) described in [1], wherein the sensor unit (10) is connected in series such that the third detection coil (33) and the fourth detection coil (34) are in opposite directions due to electromagnetic coupling.

[0050] [4] The magnetostrictive torque sensor (1) described in [1], wherein the voltage measuring unit (9) is a lock-in amplifier.

[0051] [5] The magnetostrictive torque sensor (1) according to [1], wherein the predetermined angle is 45 degrees.

[0052] [6] The magnetostrictive torque sensor according to [1], wherein the first to fourth detection coils (31 to 34) are formed by wiring patterns formed on a flexible substrate (6).

[0053] Although embodiments of the present invention have been described above, the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. In addition, the present invention can be implemented with appropriate modifications without departing from its spirit. [Explanation of Symbols]

[0054] 1…Magnetostrictive torque sensor (torque sensor) 2…Magnetostrictive material 3…Detection coil 31...First detection coil 32...Second detection coil 33...Third detection coil 34…Fourth detection coil 31a, 33a...first straight section 32a, 34a…Second straight section 6… Flexible circuit board 8…Drive unit 9...Voltage measurement section 10...Sensor part

Claims

1. A torque sensor for detecting torque transmitted by a magnetostrictive material having magnetostrictive properties, A sensor unit having a pair of first and third detection coils having a first linear portion inclined at a predetermined angle with respect to the axial direction of the magnetostrictive material and arranged to be electromagnetically coupled to each other, and a second and fourth detection coil having a second linear portion inclined at a predetermined angle in the direction opposite to the first linear portion with respect to the axial direction of the magnetostrictive material and arranged to be electromagnetically coupled to each other, A drive unit that applies an AC drive voltage to the first detection coil and the second detection coil, The system comprises a voltage measuring unit that measures the voltage generated by electromagnetic coupling between the third detection coil and the fourth detection coil, The sensor unit is configured such that the third detection coil and the fourth detection coil are connected in series such that the direction of the voltage generated by electromagnetic coupling is in opposite directions. Magnetostrictive torque sensor.

2. The voltage measurement unit consists of a lock-in amplifier. The magnetostrictive torque sensor according to claim 1.

3. The predetermined angle is 45 degrees. The magnetostrictive torque sensor according to claim 1.

4. The first to fourth detection coils are composed of wiring patterns formed on a flexible substrate. The magnetostrictive torque sensor according to claim 1.

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