JP2697846B2 - Torque sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the invention]

(Industrial application field) The present invention relates to a magnetostrictive torque sensor used for detecting a torque applied to a shaft to be measured. (Prior art) Conventionally, as this type of magnetostrictive torque sensor,
For example, there is a structure shown in FIG. The magnetostrictive torque sensor 21 shown in FIG. 6 has a gap 23 between the measured shaft 22 and the outer periphery of the measured shaft 22 made of a magnetic material having a magnetostrictive effect. Yoke 24 made of high permeability material of
In the yoke 24, an exciting coil 25 as exciting means for forming a magnetic circuit in which the measured shaft 22 is part of a magnetic path,
It has a structure provided with a detection coil 26 as detection means for detecting a magnetostrictive component passing through the shaft 22 to be measured. In the magnetostrictive torque sensor 21 having such a structure, the magnetic flux generated from the exciting coil 25 is supplied to the exciting coil 25 so that the magnetic flux emitted from the exciting coil 25 is changed to the measured shaft 22 → the gap 23 → the yoke 24 →
A magnetic circuit is formed that passes from the gap 23 to the shaft 22 to be measured. At this time, an induced electromotive force is generated in the detection coil 26. In the state where the induced electromotive force is generated, when a torsional torque is applied to the measured shaft 22, the magnetic permeability of the measured shaft 22 itself changes due to the magnetostrictive effect of the measured shaft 22. A change occurs in the magnetic flux density, and the induced electromotive force generated by the detection coil 26 due to self-induction changes. By detecting the change in the induced electromotive force, a torque-output characteristic as shown in FIG. Thus, the torsional torque applied to the measured shaft 22 can be detected. (Problems to be Solved by the Invention) However, when it is intended to detect a torsional torque applied to a generally used power transmission shaft (for example, a drive shaft, a column shaft, etc.), the magnetostriction of the structure shown in FIG. When an attempt is made to adopt the power transmission shaft itself as the measured shaft 42 using the torque sensor 21 of the formula, the power transmission shaft is made of ordinary mechanical structural steel (JIS SC,
SCr, SCM, SNCM, etc.), the amount of detection of the magnetostriction effect is small, and the angle θ showing sensitivity in the output characteristic diagram shown in FIG. 7 is small.
A sufficient detection sensitivity cannot be obtained, and the width h showing hysteresis in the output characteristic diagram also shown in FIG.
However, there is a problem that it is difficult to accurately detect torque. (Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and in particular, uses a rotating shaft itself to which a relatively large torque is applied, such as a power transmission shaft, as a shaft to be measured. When trying to detect the torque applied to the rotating shaft, ensure sufficient strength required for the power transmission shaft, increase the detection sensitivity required for the measured shaft of the torque sensor, and reduce the hysteresis. It is an object of the present invention to solve the above-described problem by providing a torque sensor capable of accurately detecting torque. The present inventors have previously described Japanese Patent Application No. 61-226062 (Japanese Patent Application
No. 81993), etc., have been developing a shaft to be measured for a torque sensor having a large detection sensitivity and a small hysteresis, but in the present invention, in particular, to find the effects of Si, Al, Co, etc.
Furthermore, a torque sensor has been developed in which the detection sensitivity is increased and the hysteresis is reduced so that the torque can be accurately detected.

Configuration of the Invention

(Means for Solving the Problems) The present invention detects an axis to be measured, exciting means for forming a magnetic circuit having the axis to be measured as a part of a magnetic path, and a magnetostrictive component passing through the axis to be measured. In the torque sensor having the detecting means, at least a part of the shaft to be measured, in particular, a part or the whole forming the magnetic path, is expressed by C: 0.1 by weight%.
~ 1.5%, Si: More than 0: 4.0% or less (However, 0.5% or more when not containing Co), Mn: More than 0, 3.0% or less, Al: More than 0
3.0% or less, and one or both of Ni: 5.0% or less and Cr: 5.0% or less, and if necessary
Co: more than 0 and 5.0% or less, Pb: 0.5% or less, Bi: 0.5% or less, S: 0.5% or less, P: 0.3% or less, Te: 0.5% or less, Se: 0.5% or less as required Ca: 1 selected from among 0.05% or less
Including seeds or two or more, if necessary, Cu: 1.0%
Mo, 1.0% or less, B: 0.05% or less, W: 0.5% or less, V: 0.5%
Or less, Ti: 0.5% or less, Nb: 0.5% or less, Ta: 0.5% or less, Zr: 0.5
% Or less, Hf: 0.5% or less, N: 0.1% or less, and the balance is made of steel having a composition consisting of Fe and impurities. It is characterized in that the configuration is a means for solving the above-mentioned problem. As described above, a torque sensor according to the present invention detects an axis to be measured, an exciting unit forming a magnetic circuit in which the axis to be measured is a part of a magnetic path, and detects a magnetostrictive component generated in the axis to be measured. In this case, for example, the exciting means and the detecting means can be constituted by separate coils, that is, an exciting coil and a detecting coil, or a common coil. It is also possible to adopt a configuration in which a change in inductance due to a change in the magnetic permeability of the coil is detected. Further, the measured shaft may be formed with a concavo-convex portion forming a predetermined angle with respect to the axial direction thereof so as to impart a shape with magnetic anisotropy. It is possible to adopt other various structures without being limited to. In the magnetostrictive torque sensor according to the present invention, at least a part of the shaft to be measured, in particular, a portion forming a magnetic path, or the whole of the shaft to be measured is made of steel having the above-described specific component. The reason for limiting the component composition (% by weight) is described below. C: 0.1 to 1.5% C is an element necessary for securing the strength required for a shaft to be measured, for example, a power transmission system such as a drive shaft or a column shaft or other shaft structures. To obtain 0.1% or more. However, if the content is too large, the toughness is rather lowered and the cold workability is adversely affected. When carburizing treatment is performed, the C content is preferably set to 0.35% or less so that the C content in the carburized layer becomes 1.5% or less. Si: more than 0: 4.0% or less Si has the effect of increasing sensitivity and reducing hysteresis. And 0 when not including Co.
If it is less than 5%, the sensitivity cannot be sufficiently improved, so Co
If not contained, it is particularly desirable to contain 0.5% or more. Further, Si acts as a deoxidizing agent on the steelmaking magnet and is an effective element for increasing the strength. However, if it is too much, it lowers the toughness. Mn: more than 0 and less than 3.0% Mn acts as a deoxidizing agent and a desulfurizing agent during steelmaking, and is an effective element for improving the hardenability of steel and increasing the strength. Is reduced to 3.0% or less. Al: more than 0 and 3.0% or less Al has the effect of increasing sensitivity and reducing hysteresis similarly to Si. In addition, there is an effect that the crystal grains of steel are made finer, and the wear resistance and fatigue strength of the surface are increased. This Al is a particularly effective element when performing a nitriding treatment. However, if the content exceeds 3.0%, the toughness is reduced. Co: more than 0: 5.0% or less Co has the effect of increasing the detection sensitivity similarly to Si and Al, so it may be added as necessary, and in this case, the Si content may be less than 0.5%. However, if Co is contained in a large amount, it increases hysteresis and lowers the hardenability of steel. Therefore, even if Co is added, it is better to be 5.0% or less. Ni: 5.0% or less Cr: 5.0% or less Ni, Cr is an element effective for improving the hardenability of steel and strengthening the fabric to improve the strength. In this case, if the content of Ni is increased, the sensitivity is improved (that is, the angle θ in FIG. 3 is increased), but the hysteresis is increased (that is, the width h in FIG. 3 is increased). % Or less. When the Cr content is increased to some extent, the hysteresis tends to decrease (that is, the width h in FIG. 3 decreases), but the sensitivity decreases (that is, the angle θ in FIG. 3 decreases). As a result, if the Cr content is too large, the hysteresis tends to increase again. Pb: 0.5% or less, Bi: 0.5% or less, S: 0.5% or less, P: 0.3% or less,
One or more selected from Te: 0.5% or less, Se: 0.5% or less, Ca: 0.05% or less These elements improve the free-cutting properties of steel materials and increase the measured shaft (other power transmission shafts). And the like). Cu: 1.0% or less Mo: 1.0% or less Both Cu and Mo are effective elements for strengthening the steel matrix and improving the strength, and therefore may be added as necessary. However, if the amount of Cu is too large, hot workability is reduced, and if the amount of Mo is too large, toughness is reduced. Therefore, even when added, Cu is preferably 1.0% or less and Mo is also preferably 1.0% or less. In addition, to improve the hardenability of steel, B is 0.05%
% Or less, or to improve the strength by crystal grain refinement or precipitation hardening, W is 0.5% or less, V is 0.5% or less, Ti is 0.5% or less, Nb is 0.5% or less, and Ta is 0.5% or less. % Or less, Zr
One or more of these may be added in a range of 0.5% or less, Hf of 0.5% or less, and N of 0.1% or less. The shaft to be measured used in the torque sensor according to the present invention is made of steel having the above composition.However, if necessary, the hysteresis is further reduced, and the output sensitivity and the output sensitivity of each shaft to be measured are also determined. In order to reduce the variation in hysteresis and increase the wear resistance and fatigue strength of the surface, besides the usual quenching and tempering, for example, carburizing and quenching, and carburizing, quenching and tempering It is also desirable to perform carburizing / nitriding treatment, nitriding treatment, induction quenching / tempering treatment, if necessary. For example, the C content of the carburized layer is set to be more than 0.1% and 1.5% or less. It is also desirable if necessary. (Embodiment) FIG. 1 shows a torque sensor according to an embodiment of the present invention. The torque sensor 1 shown in FIG. 1 uses a shaft 2 to be measured which is entirely made of steel having a composition as described later. The concave portions 3a, 3b and the convex portions 4a, 4b forming a predetermined angle are formed integrally with the shaft to be measured 2 at an appropriate interval, and are formed by the concave portions 3a, 3b and the convex portions 4a, 4b. It has a shape magnetic anisotropy. In this case, the one concave portion 3a and the convex portion 4a and the other concave portion 3b and the convex portion 4b have the same inclination angle (for example, 45 ° in this embodiment) with respect to the axial direction and are mutually opposite. They are provided as a pair in a state inclined in the opposite direction. In addition, the torque sensor 1 faces the concave portion 3a and the convex portion 4a formed on the measured shaft 2 and the concave portion 3b and the convex portion 4b formed on the measured shaft 2 in addition to the shaft 2 to be measured. And a pair of coils 5a and 5b arranged
A cylindrical yoke 7 made of a material having a high magnetic permeability is provided outside the a and 5b and with a gap 6 between the shaft 2 to be measured and the shaft 2 to be measured. In this case, the coils 5a and 5b are used in common for excitation means constituting a magnetic circuit having the measured shaft 2 as a part of a magnetic path and for detecting means for detecting a magnetostrictive component passing through the measured shaft 2. It is something to be done. In the torque sensor 1 having such a structure, the coil 5
As shown in FIG. 2, a and 5b are combined with resistors 11 and 12 to form a bridge circuit. The bridge circuit is provided with a variable resistor 13 for balance, and a connection point A of the bridge circuit. , C, an excitation oscillator 14 is connected to adjust the excitation direction to the same direction, and a differential amplifier 15 is connected between the connection points B, B ′.
Are connected so that the detection output can be taken out from the output terminals 16 and 17. Next, the operation when the torque sensor 1 shown in FIG. 1 is connected to the electric circuit shown in FIG. 2 will be described. First, upon operation, the excitation oscillator 14
An alternating current having a constant amplitude (V) and a frequency (f) is applied to 5a and 5b. Due to this energization, the lines of magnetic force having the magnetic path of the measured shaft 2 → the gap 6 → the yoke 7 → the gap 6 → the measured shaft 2 are generated so as to surround the coils 5a and 5b. By the way, when the frequency (f) of the alternating current to be energized is increased, the eddy current increases in the shaft 2 to be measured. The distribution of the eddy current is stronger as it is closer to the center of the shaft 2 to be measured, and becomes zero on the surface. Therefore, even if the magnetization on the surface can follow the change in the external magnetic field, the change in the magnetization is hindered on the inside. Therefore, the magnetic field lines flow on the surface portion of the shaft 2 to be measured, and the concave portions 3a and 3b are formed on the shaft 2 to be measured.
Is formed so as to form a predetermined angle with respect to the axial direction of the shaft, and this becomes a magnetic resistance and flows mainly through the convex portions 4a and 4b. Therefore, the effect of shape magnetic anisotropy due to the concave portions 3a, 3b and the convex portions 4a, 4b appears. The angles of the concave portions 3a, 3b and the convex portions 4a, 4b with respect to the axial direction are such that one concave portion 3a and the convex portion 4a and the other concave portion 3b and the convex portion 4b are in opposite directions and equal to each other. Although it is assumed that the axis has an angle, it is most preferable that the angle is in the main stress direction when torque is applied to the measured shaft 2, that is, in the right 45 ° direction and the left 45 ° direction. is there. The reason for this is that the lines of magnetic force mainly flow in the main stress direction, and the convex portions 4a and 4b are the outermost surface portions of the shaft 2 to be measured. This is because it can be extracted most effectively. When a torque is applied to the shaft 2 to be measured in the direction T shown in FIG. 1, the one convex portion 4a is formed in the right 45 ° direction, so that the maximum tensile stress + σ acts, Conversely, since the other convex portion 4b is formed in the left 45 ° direction, the maximum compressive stress −σ acts. Here, if the measured shaft 2 has a positive magnetostriction effect, the magnetic permeability of one convex portion 4a increases as compared to when the torque is zero, and conversely, the magnetic permeability of the other convex portion 4b increases. The permeability decreases as compared to the case where the torque is zero. Therefore, the inductance of one coil 5a increases and the inductance of the other coil 5b decreases,
The balance of the bridge circuit shown in FIG. 2 is lost, and an output corresponding to the torque is generated between the output terminals 16 and 17. Further, when the torque is applied in the opposite direction, the inductance of one coil 5a decreases and the inductance of the other coil 5b increases due to the action opposite to that described above. The balance of the bridge circuit is lost, and an output corresponding to the torque is generated between the output terminals 16 and 17. More specifically, the inductances of the coils 5a and 5b are L ₁ and L ₂ , the resistance values of the resistors 11 and 12 are R, the voltage of the excitation oscillator 14 is V, and the frequency is f. When the current flowing through the bridge circuit ABC is i ₁ and the current flowing through the circuit AB′-C is i ₂ , , And the potential V ₁ of the point B, the potential V ₂ of _{V 1 = i 1 · R B} ' point, the V ₂ = i ₂ · R. Therefore, the potential difference of BB ′ is | V ₁ −V ₂ | Is obtained by the differential amplifier 15 to detect the torque. In the torque sensor 1 of this embodiment, the concave portions 3a, 3
b and the convex portions 4a and 4b have a pair of opposite inclinations, the coils 5a and 5b are respectively opposed to each other, and the difference in magnetic change between the concave portions 3a and 3b and the convex portions 4a and 4b is determined. Since the detection is performed by the bridge circuit, even if the magnetic permeability of the shaft 2 to be measured changes with the temperature, the zero point of the output can be fixed and the detection accuracy of the torque can be high. It is possible. First, in the torque sensor 1 shown in FIG. 1, the measured shaft 2 has C: 0.20%, Si: (0.25 to 5.0)%, Mn: 0.7%, Cu: 0.
Made of steel containing 1%, Ni: 0.1%, Cr: 1.0%, Mo: 0.15%, Al: 0.03%, Si 0.25%, 0.5%, 1.0%, 2.0%, 4.0%, 5.0
% To examine the effect of Si on the sensor characteristics. Then, each of the steels having the above-described components was melted in a vacuum induction furnace by 50 kg each and then forged to produce a round bar having a diameter of 20 mm. Each of the above-mentioned round bars is used to form the shaft 2 to be measured shown in FIG. 1, and has a concave portion having a width of 2 mm and a depth of 1 mm having a predetermined angle (45 ° in the embodiment) in the axial direction. The shaft 3 to be measured is formed by integrally forming the projections 3a and 3b and the projections 4a and 4b. Each shaft 2 to be measured was carburized at 910 ° C. for 3 hours and then quenched in oil. Thereafter, tempering was performed at 170 ° C. for 2 hours. Next, the torque sensor 1 using each of the measured shafts 2 described above.
In the above, by supplying an alternating current having a frequency of 30 kHz and a current of 30 mA from the excitation oscillator 14 to the coils 5a and 5b, the measured shaft 2 → the gap 6 → the yoke 7 → the gap 6 → the measured shaft 2 is used as a magnetic path. FIG. 2 shows a change in the magnetic permeability of the shaft 2 to be measured when a magnetic circuit was formed and a torque of 20 kgf · m was applied in the left-right rotation direction in this state as an inductance change in the coils 5a and 5b. As a result of detection by the AC bridge, the output of each torque sensor 1 at this time is as shown in FIG. 3, and the output sensitivity (the angle θ in FIG. 3) at this time was examined. The result is shown in FIG. As is clear from the results shown in FIG. 4, the sensitivity increases with an increase in the amount of Si. However, when the content exceeds 4%, a significant effect on the increase in the sensitivity is not recognized. Next, in the torque sensor 1 also shown in FIG. 1, the shaft 2 to be measured was made of steel having a chemical composition as shown in Table 1. Then, in exactly the same manner as in the previous embodiment, the steel of each component was melted, and then the shaft 2 to be measured as shown in FIG. 1 was produced. Then, the inventive examples No. 1 to No. 14 and the comparative examples No. 15, 1
A heat treatment was performed on the shaft 2 to be measured 6 under the same conditions as shown in Table 1. Next, in the torque sensor 1 using each of the above-described measured shafts 2, the output characteristics of each torque sensor 1 were examined in exactly the same manner as in the previous embodiment, and the results were as shown in FIG. Were examined for output sensitivity (angle θ in FIG. 3) and hysteresis (width h in FIG. 3). These results are also shown in Table 1. As is clear from the results shown in Table 1, when the measured axis 2 of the present invention examples No. 1 to 14 satisfying the conditions of the present invention, both the sensitivity and the hysteresis show good values. ing. Then, it was recognized that the use of the measured shaft 2 subjected to the carburizing treatment had slightly better hysteresis than the case where the carburizing treatment was not performed. On the other hand, in the case of Comparative Example No. 15 which does not satisfy the conditions of the present invention, for example, the Ni content exceeds 5.0%, although the sensitivity is good, the hysteresis is large, and the steel does not contain Co and contains Si. In the case of Comparative Example No. 16 in which the amount is less than 0.5%,
Although the hysteresis was small, the sensitivity showed a low value. Subsequently, in the torque sensor 1 also shown in FIG. 1, the measured shaft 2 has C: 0.20%, Si: 0.2% and 1.0%, Mn:
0.7%, Cu: 0.1%, Ni: 0.1%, Cr: 1.0%, Mo: 0.15%, Al: 0.03
%, Co: Two kinds of steel containing (0.01-6.0)%
Was changed to 0.01%, 0.5%, 1.0%, 2.0%, 3.0%, and 5.0%, and the effect of Co on the sensor characteristics was examined. Then, each of the steels having the above-described components was melted in a vacuum induction furnace by 50 kg each and then forged to produce a round bar having a diameter of 20 mm. Each of the above-mentioned round bars is used to form the shaft 2 to be measured shown in FIG. 1, and has a concave portion having a width of 2 mm and a depth of 1 mm having a predetermined angle (45 ° in the embodiment) in the axial direction. The shaft 3 to be measured is formed by integrally forming the projections 3a and 3b and the projections 4a and 4b. Each shaft 2 to be measured was carburized at 910 ° C. for 3 hours and then quenched in oil. Thereafter, tempering was performed at 170 ° C. for 2 hours. Next, the torque sensor 1 using each of the measured shafts 2 described above.
In the above, by supplying an alternating current having a frequency of 30 kHz and a current of 30 mA from the excitation oscillator 14 to the coils 5a and 5b, the measured shaft 2 → the gap 6 → the yoke 7 → the gap 6 → the measured shaft 2 is used as a magnetic path. FIG. 2 shows a change in the magnetic permeability of the shaft 2 to be measured when a magnetic circuit was formed and a torque of 20 kgf · m was applied in the left-right rotation direction in this state as an inductance change in the coils 5a and 5b. As a result of detection by the AC bridge, the output of each torque sensor 1 at this time is as shown in FIG. 3, and the output sensitivity (the angle θ in FIG. 3) at this time was examined. The results are shown in FIG. As is clear from the results shown in FIG. 5, it was recognized that the sensitivity increased with the increase of the Co content, and the Si content was reduced.
Good sensitivity was apparent even at less than 0.5%, and it was found that sensitivity was further increased when the Si content was 1.0%. Next, in the torque sensor 1 also shown in FIG. 1, the shaft 2 to be measured was made of steel having a chemical composition as shown in Table 2. Then, in exactly the same manner as in the previous embodiment, the steel of each component was melted, and then the shaft 2 to be measured as shown in FIG. 1 was produced. And, the present invention examples No. 21 to No. 34 and Comparative Example No. 35,
The heat treatment was performed on the 36 shafts 2 to be measured under the same conditions as shown in Table 2. Next, in the torque sensor 1 using each of the above-described measured shafts 2, the output characteristics of each torque sensor 1 were examined in exactly the same manner as in the previous embodiment, and the results were as shown in FIG. Were examined for output sensitivity (angle θ in FIG. 3) and hysteresis (width h in FIG. 3). These results are also shown in Table 2. As is clear from the results shown in Table 2, when the measured axis 2 of the present invention examples Nos. 21 to 34 satisfying the conditions of the present invention, both the sensitivity and the hysteresis show good values. I have. Then, it was recognized that the use of the measured shaft 2 subjected to the carburizing treatment had slightly better hysteresis than the case where the carburizing treatment was not performed. On the other hand, in the case of Comparative Example No. 35 which does not satisfy the conditions of the present invention, for example, the Co content exceeds 5.0%, or the Ni content is 5.
In the case of Comparative Example No. 36 exceeding 0%, the sensitivity was good, but the hysteresis showed a considerably large value. In the above embodiment, the torque sensor 1 in which the coils 5a and 5b are commonly used for the coil for the excitation means and the coil for the detection means has been described as an example. In addition, the torque sensor 21 illustrated in FIG. As shown in the figure, a yoke 24 made of a material having a high magnetic permeability is provided on the outer peripheral portion of the measured shaft 22 with a gap 23 between the measured shaft 22 and the yoke 24 as an exciting means. And a detection coil 26 serving as a detection unit may be provided, and there is no particular limitation.

【The invention's effect】

As described above, the present invention provides an axis to be measured, exciting means for forming a magnetic circuit having the axis to be measured as a part of a magnetic path, and detecting means for detecting a magnetostrictive component passing through the axis to be measured. Wherein at least a part of the measured shaft is C: 0.1-1.5% by weight, and Si exceeds 0: 4.
0% or less (however, 0.5% or more when not containing Co), M
n: more than 3.0% and below, Al: more than 3.0% and below, and Ni:
Including one or both of 5.0% or less and Cr: 5.0% or less, and more than Co: 0 and 5.0% or less, if necessary, Pb: 0.5% or less, Bi: 0.5% or less as necessary , S:
0.5% or less, P: 0.3% or less, Te: 0.5% or less, Se: 0.5% or less, C
a: Contains one or more selected from 0.05% or less, and also, as required, Cu: 1.0% or less, Mo: 1.0% or less, B: 0.05% or less, W: 0.5% or less, V : 0.5% or less, Ti: 0.5% or less, Nb: 0.5% or less, Ta: 0.5% or less, Zr: 0.5% or less, Hf: 0.5%
Hereinafter, N: one or more selected from 0.1% or less, and the balance is made of steel having a composition composed of Fe and impurities, so that the strength of the shaft to be measured is sufficiently secured. In addition, sufficient output sensitivity required for torque detection can be ensured, and the hysteresis can be reduced, so that the torque can be accurately detected. In particular, when detecting a torque applied to a rotating shaft having a large load, such as a power transmission shaft, as a measured shaft, the strength of the rotating shaft is sufficiently secured and the torque detection sensitivity is determined. At the same time, the hysteresis can be reduced, and the torque applied to the stationary shaft as well as the rotating shaft can be accurately detected. The effect is brought.

[Brief description of the drawings]

FIG. 1 is an axial cross-sectional explanatory view showing a structural example of a torque sensor to which the present invention is applied, FIG. 2 is an explanatory view illustrating the configuration of an electric circuit connected to the torque sensor of FIG. 1, and FIG. FIG. 4 is a graph showing the output characteristics of the torque sensor of FIG. 1, and FIG.
FIG. 5 is a graph illustrating the result of examining the effect of the amount of Si on the sensitivity of the sensor characteristics, FIG. 5 is a graph illustrating the result of examining the effect of the amount of Co on the sensitivity of the sensor characteristics, and FIGS. 6 (a) and (b). 7) is an explanatory diagram in the axial direction and an explanatory diagram perpendicular to the axis, respectively, showing other structural examples of the torque sensor. FIG. 7 is a graph showing the output characteristics of the torque sensor in FIG. 1,21 ... Torque sensor, 2,22 ... Measured axis, 5a, 5b ...
Coil (excitation means and detection means), 25 ... excitation coil (excitation means), 26 ... detection coil (detection means).

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-225182 (JP, A) JP-A-63-81993 (JP, A) JP-A-62-264685 (JP, A)

Claims (8)

(57) [Claims] 1. A torque sensor comprising: an axis to be measured; exciting means for forming a magnetic circuit having the axis to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the axis to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1 to 1.5%, Si: 0.5 to 4.0%, Mn: 0 to 3.0% or less,
Al: More than 0: 3.0% or less, and Ni: 5.0% or less and Cr: 5.0%
A torque sensor comprising one or both of the following and a balance made of steel having a composition comprising Fe and impurities. 2. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1 to 1.5%, Si: 0.5 to 4.0%, Mn: 0 to 3.0% or less,
Al: More than 0: 3.0% or less, and Ni: 5.0% or less and Cr: 5.0%
Including one or both of the following, and further comprising:
b: 0.5% or less, Bi: 0.5% or less, S: 0.5% or less, P: 0.3% or less, T
e: 0.5% or less, Se: 0.5% or less, Ca: 0.05% or less, selected from the group consisting of two or more, and the balance is made of steel having a composition of Fe and impurities. Torque sensor. 3. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1 to 1.5%, Si: 0.5 to 4.0%, Mn: 0 to 3.0% or less,
Al: More than 0: 3.0% or less, and Ni: 5.0% or less and Cr: 5.0%
Including one or both of the following, and further comprising:
u: 1.0% or less, Mo: 1.0% or less, B: 0.05% or less, W: 0.5% or less,
One or two selected from V: 0.5% or less, Ti: 0.5% or less, Nb: 0.5% or less, Ta: 0.5% or less, Zr: 0.5% or less, Hf: 0.5% or less, N: 0.1% or less A torque sensor comprising a steel containing at least one species and a balance of Fe and impurities. 4. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1 to 1.5%, Si: 0.5 to 4.0%, Mn: 0 to 3.0% or less,
Al: More than 0: 3.0% or less, and Ni: 5.0% or less and Cr: 5.0%
Including one or both of the following, and further comprising:
b: 0.5% or less, Bi: 0.5% or less, S: 0.5% or less, P: 0.3% or less, T
e: 0.5% or less, Se: 0.5% or less, Ca: 0.05% or less, one or more selected from among them, Cu: 1.0% or less, Mo: 1.0% or less, B: 0.05% or less , W: 0.5% or less, V: 0.5% or less, Ti: 0.5% or less, Nb: 0.5% or less, Ta: 0.5% or less, Zr: 0.5%
1 selected from the following, Hf: 0.5% or less, N: 0.1% or less
A torque sensor characterized in that the torque sensor is made of a steel containing one or more kinds and a balance of Fe and impurities. 5. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1-1.5%, Si: More than 0 and 4.0% or less, Mn: More than 0: 3.0%
The composition below contains at least one of Al: more than 3.0% and less, Co: more than 5.0% and less, and Ni: less than 5.0% and Cr: less than 5.0%, with the balance being Fe and impurities. A torque sensor characterized by using a steel having a material as a material. 6. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1-1.5%, Si: More than 0 and 4.0% or less, Mn: More than 0: 3.0%
In the following, Al: more than 3.0% or less, Co: more than 5.0% or less, and one or both of Ni: 5.0% or less and Cr: 5.0% or less, and Pb: 0.5% or less, Bi: 0.5% or less,
S: 0.5% or less, P: 0.3% or less, Te: 0.5% or less, Se: 0.5% or less,
Ca: a torque sensor characterized by containing one or more kinds selected from 0.05% or less, and using a steel having a composition of Fe and impurities as a balance. 7. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1-1.5%, Si: More than 0 and 4.0% or less, Mn: More than 0: 3.0%
In the following, Al: more than 3.0% and less, Co: more than 5.0%, and one or both of Ni: 5.0% or less and Cr: 5.0% or less, and further, Cu: 1.0% or less, Mo: 1.0% or less,
B: 0.05% or less, W: 0.5% or less, V: 0.5% or less, Ti: 0.5% or less,
Contains one or more selected from Nb: 0.5% or less, Ta: 0.5% or less, Zr: 0.5% or less, Hf: 0.5% or less, N: 0.1% or less, with the balance being Fe and impurities A torque sensor characterized by using steel having a composition as a material. 8. A torque sensor comprising: a shaft to be measured; exciting means for forming a magnetic circuit having the shaft to be measured as a part of a magnetic path; and detecting means for detecting a magnetostrictive component passing through the shaft to be measured. , At least a part of the axis to be measured is, by weight%,
C: 0.1-1.5%, Si: More than 0 and 4.0% or less, Mn: More than 0: 3.0%
In the following, Al: more than 3.0% or less, Co: more than 5.0% or less, and one or both of Ni: 5.0% or less and Cr: 5.0% or less, and Pb: 0.5% or less, Bi: 0.5% or less,
S: 0.5% or less, P: 0.3% or less, Te: 0.5% or less, Se: 0.5% or less,
Ca: contains one or more selected from 0.05% or less, and further contains Cu: 1.0% or less, Mo: 1.0% or less, B: 0.05%
Or less, W: 0.5% or less, V: 0.5% or less, Ti: 0.5% or less, Nb: 0.5%
Or less, Ta: 0.5% or less, Zr: 0.5% or less, Hf: 0.5% or less, N: 0.1
% Or one or more selected from the following:
A torque sensor characterized in that the balance is made of steel having a composition comprising Fe and impurities.