JPH02281117A - Torque detecting apparatus for rotary shaft - Google Patents

Abstract

PURPOSE:To improve detecting sensitivity and accuracy by constituting an oscillating circuit which is oscillated at the resonant frequency of an optical oscillating circuit with a resonant circuit and a detecting part, and detecting the difference in rotary angles corresponding to torque as the change in oscillating frequency. CONSTITUTION:A rotary shaft 1 is a driving shaft, and a rotary shaft 2 is a driven shaft. Then, the shaft 2 is rotated with the shaft 1. Torsion is generated in an elastic body which is provided between both shafts 1 and 2. Therefore, a rotary angle is generated. The gaps between detecting coils 31 and 33 and metal cores 32 and 34 changes. The inductances of the coils 31 and 33 changes. Namely, when a core part 21 of the core 32 is moved back and forth in the cavity part of the coil 31, the eddy current generated in the core 32 changes, and the inductance of the coil 31 changes. With this change, the resonant frequency of an LC series circuit Kx which is coupled with a sensor part Jx changes. The oscillating frequency in a detecting part Lx changes based on said change. Thus an output fx is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides two methods for accurately determining the axis I and the torque of a rotating shaft of a steering shaft robot arm of a vehicle, a rotating machine, etc.
The present invention relates to a rotating shaft torque detection device that can perform non-contact measurement.

[Prior art]

As shown in Fig. 23, the conventional means for measuring the shaft torque of nine rotating shafts is a torsion shaft S that twists and changes with torque, and three ring-shaped cores (magnetic iron cores) 91 arranged concentrically.
, 92.93 has been proposed (Japanese Unexamined Patent Publication No. 63-36124). And the inner 2
Two rings 92° 93 are connected to both ends of the torsion shaft S by brackets 921° 931, respectively, and both rings 92
The opposing surfaces of 93 define tooth profiles 92A, 92B, 93A, 93B, and the outer ring 91 has stationary supported detection coils 91A, 91B. In this torque sensor, when torque is applied, the torsion shaft S twists, and the ring-shaped core 92
The opposing areas of the tooth profiles 92A and 92B at 93 and 93A and 93B change.

As a result, the number of magnetic lines of force 90.90 changes, and the detection coil 9
The inductances of 1A and 91B change.

Since the amount of change in inductance corresponds to the amount of torque, the amount of torque can be detected thereby.

The applicant for one application is as shown in Figure 24.

An application was filed for a torque detection device consisting of a drive shaft 1 and a driven shaft 2 connected by an elastic body 10, which were provided with a resonant circuit and a detection section consisting of detection coils 99A, 998, etc. (Japanese Patent Application No. 62-263490). The above detection coils 99A, 99
A solenoid coil 95 is wound around the drive shaft 1, and the solenoid coil 95 and the two detection coils 99A and 99B are connected in series through a capacitor 9B. to form a resonant circuit. Further, a detection section consisting of an input coil 96 and an output coil 97 is arranged at an interval around the outer periphery of the solenoid coil 95. The detection coil 99A99B has a conductive wire wound around a core made of magnetic material. This torque detection device is
When a rotation angle difference occurs between the two shafts 1 and 2 due to torque,
The opposing area between the pair of detection coils 99A and 99B changes, the number of magnetic lines of force changes, the mutual inductance of the detection coils changes, and the overall inductance changes.

Therefore, the amount of torque can be detected.

[Problem to be solved]

However, since the former torque sensor using three ring-shaped cores uses a core made of magnetic (A) material, the inductance has temperature dependence.

Although the temperature dependence at the zero point can be reduced due to differential detection, the temperature dependence of the sensitivity is large.

The latter torque detection device using a pair of detection coils uses two sets of circuits shown in FIG. 24 to perform temperature compensation, so that magnetic flux flows through the detection coils in the same direction and in opposite directions. The output is the difference or ratio of 100 outputs (positive phase and negative phase) (third embodiment of the same application). However, since a core made of a magnetic material is used for the detection coil, the temperature dependence of each coupling coefficient that determines mutual inductance is different.

Therefore, temperature compensation cannot be performed sufficiently.

That is, the mutual inductance is determined by the coupling coefficient of the two detection coils, but when a core of a magnetic material (ferrite or the like) is used, the coupling coefficient also exhibits temperature dependence due to the temperature dependence of its magnetic permeability.

In addition, the degree of temperature dependence differs depending on the direction of bonding (positive phase and negative phase) and degree of bonding (opposed area), and there is a quantity that cannot be canceled (temperature compensated) even if the difference (or ratio) of the two pairs is taken. remain.

As mentioned above, all conventional torque detection devices are affected by temperature dependence and have problems with temperature characteristics.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a rotating shaft torque detection device that has excellent temperature characteristics, is highly accurate, and is capable of non-contact measurement.

[Means for solving problems]

In the present invention, an annular detection coil without a bobbin is disposed on the rotating shaft that receives torque for one rotation, and a metal core that does not have ferromagnetism is disposed. The metal core moves back and forth within the cavity of the detection coil, so that the inductance of the detection coil changes in response to the rotation angle difference. Two sets of the above-mentioned detection coils and metal cores are arranged, and one metal core has one set.
The metal core has one core part, and the other metal core has two core parts. Further, a capacitor and a solenoid coil wound around a rotating shaft are connected in series and fixed on the rotating shaft, and the detection coil, the capacitor, and the solenoid coil are connected in series to form a resonant circuit.

In addition, a detecting section is provided with an input coil and an output coil of 1 m each consisting of a magnetic core and a coil wound around the magnetic core, and the input coil and output coil of the detecting section are opposed to the solenoid coil on both sides of the front rotating shaft. and arrange them with gaps between them.

The resonant circuit and the detection section constitute an oscillation circuit that oscillates at the resonant frequency of the resonant circuit, and detects the rotation angle difference corresponding to the torque as a change in the oscillation frequency.

What should be noted in the present invention is that a detection coil is provided on the 9-rotation axis and a metal core that moves forward and backward in the cavity of the detection coil, and the inductance of the detection coil is adjusted in response to the rotation angle difference (rotation angle displacement) due to torque. changeable,
Further, a detection section is provided with a gap opposite the solenoid coil, and the rotation angle difference corresponding to the torque is detected as a change in the oscillation frequency and wave number. Further, the detection coil and the metal core constitute a sensor section.

What should be noted further is that the detection coil is an annular body without a bobbin, and two sets of the detection coil and the metal core are arranged, and one of the metal cores (the first metal core) is connected to one core part. The other metal core (second metal core) has two core parts.

As shown in FIGS. 1, 2, and 20, the detection coil in the sensor section uses a coil formed by winding a conducting wire in an annular shape. That is, the detection coil is constructed without a bobbin, and has a cavity in its center. The detection coil is fixed to a fixture provided on the rotating shaft, for example.

Further, the metal core is made of a non-ferromagnetic material such as copper, and is configured to be able to move forward and backward within the cavity of the detection coil. Then, the metal core is attached to a fixture provided on the 9-rotation shaft with a screw or the like so that the zero point can be adjusted (see FIG. 14).

Then, the sensor portion consisting of the detection coil and the metal core is set as a pair, facing each other, and fixed on the rotating shaft. This opposition is performed in the direction of rotation of one rotation axis.

As a result, the metal core moves in or out of the cavity of the detection coil depending on the angle difference of one rotation, and the inductance of the detection coil changes.

However, as shown in Figures 1, 10, and 18, of the two metal cores, the first metal core with one core part has a large outer diameter at the center and a small outer diameter at both ends. There is. The maximum diameter portion (core portion) and the small diameter portions at both ends change at right angles as shown in FIG.
There are some that change in an inclined manner as shown in the figure.

On the other hand, as shown in FIGS. 2, 11, and 19, the second metal core having two core portions has a small outer diameter at the center and a large outer diameter at both ends.

The distance between this maximum diameter part (core part) and the small diameter part therebetween varies at right angles as shown in FIG. 19, and in some cases it changes obliquely as shown in FIG.

Further, it is preferable that the size relationship between the detection coil and the metal core described in item 1 is linear in order to improve detection sensitivity. This will be explained in detail below.

That is, first of all, regarding the detection coil, as shown in Fig. 20, the coil width a is approximately the maximum rotation angle difference θ (torsion angle, see Fig. 4) between the driving shaft and the driven shaft, and the maximum twist at the center of the detection coil. It is preferable to set it as the amount. In other words, al
(R+r)0.

Here, R is the radius of the detection coil (Fig. 20). Further, r is the radius from the center of the rotating shaft to the detection coil mounting surface (FIGS. 3 and 4).

Next, regarding the metal core size, as shown in No. 180, for the first metal core, the width of the maximum diameter part in the central part which is the core part is d, its diameter is D2, and the width of the small diameter parts at both ends. It is preferable that a/2≦d≦2a/3 D2>1.4D. Here, a is the width of the detection coil.

By setting it within the above range, the torque detection sensitivity is improved as shown in FIG. 21.

On the other hand, regarding the second metal core, if the width of the maximum diameter part on both sides is d, its diameter is Dz, the diameter of the small diameter part between them is Dl, and the distance between the maximum diameter parts is °C, then 3a/2≦d≦ 2a,
D2>], 4D2 2a≦°C≦2.4a. By setting it within the above range, the detection sensitivity is improved as shown in FIG. 22.

In addition, among the above sensor parts, the sensor part using the first metal core exhibits a high oscillation frequency when the core part (maximum diameter part) is at the center of the detection coil (X-ray in Figure 8); It is phase. On the other hand, the sensor section using the second metal core exhibits a high oscillation frequency when either core section (maximum diameter section) on both sides of 9 approaches the center of the detection coil (Y
vA).

It is the correct aspect. The present invention detects torque with higher accuracy by combining the two (Fig. 9).

That is, in the present invention, two sets of the sensor sections are provided.

The detection coil on the first metal core side is connected (positive phase) so that the inductance decreases as the rotation angle increases;
The detection coil on the metal core side is connected (opposite phase) to increase inductance, and the difference or ratio of these two oscillation frequencies is sent to the resonant circuit as an output.

Note that it is preferable that both the detection coil and the metal core have circular cross sections, as shown in the embodiments.

This is because in the case of a circular cross section, the mutual inductance is larger than in the case of a square cross section.

Further, the two rotating shafts may be divided into a driving shaft and a driven shaft as shown in the prior art, and both may be connected by an elastic body such as a leaf spring, or they may be integrated. In the case of the former split type, the detection coil and the metal core are arranged facing each other on the drive shaft side and the driven shaft side.

In the case of the latter one-piece unit, they are similarly arranged facing each other at an appropriate distance on one rotating shaft.

Further, the solenoid coil is constructed by winding a conductive wire around a rotating shaft, and the conductive wire is connected in series with the capacitor and the detection coil. This constitutes a closed resonant circuit. Further, the input coil and the output coil of the detection section are disposed on both sides of the rotating shaft, facing the solenoid coil, with a gap between them.

book Further, the torque detection device of the present invention is applicable to a vehicle drive system.

It is particularly effective when measuring the torque of a steering system or other rotating systems without contact, or when mounted on these rotating systems to detect torque and control a two-rotation system.

[For production]

In the present invention, when torque is applied to the rotation axis.

The difference in rotation angle causes the metal core to move relatively within the cavity of the detection coil in the advancing direction or the retreating direction. Therefore, the inductance of the detection coil changes.

This is because when the amount of penetration of the metal core changes, the eddy current generated in the core changes, and the inductance of the detection coil changes.

Therefore, due to the change in inductance in the detection coil, the resonance frequency of the resonant circuit configured on the rotation axis changes, and the oscillation frequency in the detection section provided outside the rotation axis changes. Since the amount of change in inductance in the detection coil corresponds to the amount of torque, the applied torque is detected from the amount of change in one oscillation frequency.

Therefore, as mentioned above, the detection coil and the first metal core
By detecting the difference or ratio of the outputs from the two sets of sensor units consisting of the detection coil and the second metal core, it is possible to perform more accurate torque measurements even for small angular changes.

〔effect〕

According to the present invention, since a ferromagnetic metal core is not used, the eddy current in the metal core and the current flowing through the detection circuit are determined only by the geometrical position of the metal core and have no temperature dependence. Therefore, it is possible to provide a torque detection device with excellent temperature characteristics.

Furthermore, since the detection coil does not have a bobbin, the gap between the detection coil and the metal core can be narrowed. Therefore, it is possible to obtain a large change in the inductance, and the torque detection sensitivity is improved. Also,
As mentioned above, two sets of sensor sections, one for normal phase and one for reverse phase, are used.

More accurate measurement values can be obtained.

Further, a change in the resonance frequency that occurs on the one-rotation axis according to the amount of torque can be detected in a non-contact manner by a detection section provided outside the one-rotation axis. Therefore, its detection accuracy and sensitivity are extremely excellent.

In addition, since signals are transmitted to the detection unit installed outside the axis of one rotation as two frequencies using a solenoid coil, the S/N
The ratio is high, and the power of the excitation coil of the detection section can be reduced.

As described above, according to the present invention, it is possible to provide a torque detection device that has excellent temperature characteristics, excellent detection sensitivity and accuracy, and can detect torque of a rotating shaft without contact. It is also possible to measure the torque state of a stationary rotating shaft.

〔Example〕

First Embodiment A torque detection device according to this embodiment will be explained with reference to FIGS. 1 to 9. A specific example of the arrangement of the two metal cores of the detection coil will be shown in the third embodiment.

The torque detection device in this example has two independent circuits of a metal core 32 (FIG. 1) having 21 core parts and a metal core 34 (FIG. 2) having 22 core parts.

That is, first, as shown in FIG. 5, detection coils 31 and 33. Sensor parts Jx and Jy consisting of metal cores 32 or 34,
It is fixed to the diametrically opposed portions of the rotating shaft (FIGS. 3, 4, and 5).

As shown in FIG. 7, the sensor section Jx is I.

An oscillation circuit is formed together with the C series circuit Kx and the detection section Lx. Further, the sensor section Jy similarly forms a circuit together with the LC series circuit Ky and the detection section Ly.

That is, as shown in FIG. 5, first, the rotating shafts 1 and 2 are formed by interposing an elastic body (for example, a rubber elastic body or a spring material made of metal) 10 between them.

Therefore, the detection coil 31 of the sensor section Jx is
As shown in the figure, a coil is formed by winding only the conducting wire 312 without using a bobbin. It has a cavity 313 in its center. This detection coil 31
is fixed to the end 1 of the rotating shaft 1 using a fixture 16 as shown in FIG. 2, which will be described later.

On the other hand, the metal core 32 is as shown in FIG.

It consists of a shaft 322 as a small diameter portion and a core portion 321 as a thick disk-shaped maximum diameter portion provided in the middle thereof, and is made of copper. Then, with the core portion 321 inserted into the cavity 313 of the detection coil 31, it is fixed to the end portion 21 of the rotating shaft 2 using a fixture (path shown). The metal core 32 is a threaded portion 32 provided on the shirt I-322.
Screw 5 onto the fixture.

And what are the detection coil 31 and the metal core 32?

No torque is applied to the rotating shaft (rotation angle difference -〇)
At this time, the metal core 32 is arranged so that the core portion 321 is located exactly in the middle of the detection coil 31 (FIG. 3). This adjustment is performed by turning the shaft 322 of the metal core 32 using the indicator head 326 and changing the threaded length of the threaded portion 325.

When the detection coil 31 and the metal core 32 in the first part Jx have a rotation angle difference due to torque,
) The core 32 moves back and forth within the cavity 313 of the detection coil to exhibit the oscillation frequency shown by the X-rays in FIG. That is, as the core portion 321 of the metal core 32 moves away from the inside of the detection coil 31, the inductance of the seven detection coils 31 is increased (hereinafter referred to as reverse phase).

Next, as shown in FIG. 5, the LC series circuit Kx, which constitutes a resonant circuit together with the detection coil 31, includes a solenoid coil 5051 wound around the entire circumference of the rotating shaft 1, and a capacitor 59 connected in series with the solenoid coil. 7, which are fixed on the rotating shaft 1. Thus, the sensor section Jy and the X7C series circuit Kx are connected in series to form a resonant circuit.

Further, as shown in FIG. 6, the detection unit Lx that detects the resonance frequency output from the solenoid coil 50, 51 includes an input coil 65 connected to a drive power source and an output coil 75 that transmits the detected signal. Become. The input coil 65 consists of a magnetic core 651 and a coil 61.2 wound around it, and the output coil 5 consists of a magnetic core 751 and a coil 752 wound around it, both of which are small solenoid coils 2.

That is, the solenoid coils 50 and 51 are arranged and connected in series so that the current flow directions are opposite to each other with respect to the circumferential direction of the rotating shaft. Both coils 65 above
．． 75 are disposed facing each other with a gap M between the solenoid coils 50 and 51 (FIGS. 5 and 6).

Next, the sensor section Jx, LC series circuit Kx, and detection section Lx are electrically connected to a waveform shaping circuit Nx, as shown in FIG. 7, to form an oscillation circuit that emits an output fx.

Here, fx indicates the resonance frequency. In the figure, 41 is a comparator, 42 is a diode, 43 is a current limiting resistor, and ■ is a drive power source.

On the other hand, in the sensor section Jy, as shown in FIG.
The detection coil 33 is similar to the detection coil 31, and the detection coil 33 is inserted into the through hole 161 of the fixture 16. The metal core 34 is different from the metal core 32,
The shaft 343 has two maximum diameter core portions 341,
342. The small-diameter shaft 343 has a threaded portion 345 at its tip for screwing into the metal core fixing frame (path shown) and for adjusting the zero point. The detection coil 33. The metal cores 34 are arranged so as to face each other in the diametrical direction of the two rotating shafts (see FIG. 3).

Since the metal core 34 has the above-described structure, either the core portion 341 or 342 of the metal core 34 enters the cavity of the detection coil 33 when a rotation angle difference occurs due to torque. Therefore, as the nine-rotation angle difference increases, the single oscillation frequency increases, as shown by curve Y in FIG. In other words, the rotation angle difference becomes large, and the core portion 341
342 approaches the detection coil 33, it is connected in a direction in which the inductance of the detection coil 33 decreases (hereinafter referred to as positive phase).

Similarly to the sensor section JX, the sensor section Jy is connected to the LC series circuit Ky and the detection section Ly, and is also electrically connected to the waveform shaping circuit Ny.

An oscillation circuit that emits an output fy is formed. The above-mentioned C series circuit, line 31 detection section Ly, etc. are the same as the series using the metal core 32 (FIGS. 5 and 7).

Next, two effects will be explained.

In rotating shafts 1 and 2, 1 rotating shaft 1 is the drive shaft.

When the rotating shaft 2 is used as a driven shaft, the rotating shaft 2 is rotated by the rotating shaft 1, and torque is generated in both the shafts 2 and 2, causing twisting in the elastic body 10 provided between the two shafts 1.degree.

Therefore, the state shown in Fig. 3 changes to the state shown in Fig. 4.

The rotation angle θ is generated, and the detection coil 31.33 and the metal core 3
2.34 changes, and the inductance of the detection coil 31.33 changes as described above.

At this time, since the sensor parts Jx and Jy are in the positive phase and negative phase states as described above, the relationship between the angular displacement θ and the oscillation frequency is as shown by the curve X for the positive phase output fx as shown in Figure 8. , the reverse phase output ry is represented by a curve Y.

If this oscillation frequency difference (fx-fy) is used as an output, the above relationship will be expressed as a curve B shown in FIG. This curve B shows an output change that is approximately twice that of the case where only the positive phase or negative phase is used. In other words, by arranging the sensor section in two systems, one in positive phase and one in reverse phase, and outputting it, it is possible to obtain a large output (difference in oscillation frequency) for angular displacement, making it possible to perform more accurate measurements. .

Here, regarding the signal transmission from the rotation to the output, the Jx system using the metal core 32 will be explained as follows.

That is, as described above, the core portion 321 of the metal core 32 is
When the detection coil 31 moves back and forth (moves in and out to the left and right) within the cavity 313, the eddy current generated in the metal core 32 changes, and the inductance of the detection coil 31 changes. Along with this,
The resonant frequency of the LC series circuit Kx coupled to the sensor section Jx changes.

With this change, the oscillation frequency in the detection section Lx changes and is extracted as an output fx by the circuit shown in FIG.

In the detection section Lx described above, the input coil 65 and the output coil 75 catch the output signal from the solenoid coil 50, 51, and output it to the waveform shaping circuit Nx as described above. The output fx from the waveform shaping circuit is outputted as a voltage signal by well-known means such as a one-frequency voltage converter.

Therefore, since the amount of change in inductance in the detection coil corresponds to the amount of torque, it is calculated from the amount of change in 3 oscillation frequencies to 7.
Impression force ■Torque can be detected.

In this example, by combining the two systems Jx and Jy as described above, the detection accuracy is improved as shown in FIGS. 8 and 9.

Further, according to this example, the sensor section Jx is constituted by the detection coil 31 having a cavity and the metal core 32 that moves within the cavity, and since no magnetic core is used, the detection circuit The current flowing through the metal core 32 is determined only by the geometrical position of the metal core 32, and a torque detection device with excellent temperature characteristics can be provided.

Furthermore, since the detection coil 31 does not have a bobbin, the gap between the detection coil 31 and the metal core 32 can be made as small as possible, and the rate of change of the inductance increases, which improves the detection sensitivity. Further, the metal core 32 has a threaded portion 32
5 allows for position adjustment and easy zero point adjustment. These things are the detection coil 33. The same applies to the combination of metal cores 34.

Further, since the above-mentioned inductance change can be extracted outside the rotating shaft in a non-contact state, detection accuracy and sensitivity are excellent. Furthermore, since the signal is transmitted from the resonant circuit to the detection section by the solenoid coil, the S/N ratio is high and the power of the excitation coil of the detection section can be reduced.

As described above, this example has excellent temperature characteristics, sensitivity, and accuracy. A torque detection device can be obtained.

Second Embodiment In this embodiment, the shape of the metal core in the first embodiment is changed. This will be explained using FIGS. 10 to 13.

That is, in the two examples, the metal core 38 shown in FIG.
It is composed of a core part 381 as a maximum diameter part provided in the center, small diameter parts 382, 382 at both ends, and a curved surface part 383° 383 connecting these with a concave curved surface. The metal core 38.

It forms a pair with the detection coil 31.

In addition, the metal core 19 shown in FIG.
and a curved surface portion 394 connecting these with a convex curved surface.
, 395. The metal core 39 forms a pair with the detection coil 33.

When these were attached to the device of the first embodiment and measured,
As shown in FIG. 12, the oscillation frequency of a straight line Z1 is output from the metal core 38, and the oscillation frequency of a straight line Z2 is output from the metal core 39. Therefore, as in the first embodiment, 1:2l-22
), it is possible to obtain a large output Z3 with respect to the angular displacement, as shown in FIG. 13, and the accuracy is improved.

The oscillation frequency (FIGS. 12 and 13) with respect to the angular displacement in the metal core 38 and 39 of this example is as follows.
．． It is straighter than that of No. 34 (FIGS. 8 and 9). This output state is such that the metal core 38 of the wooden example covers the concave curved surface portion 383, the metal core 39 covers the convex curved surface portion 394,
By having 395.

Third Embodiment This embodiment shows a specific example of the arrangement of each element of the torque detection device shown in the first embodiment. This will be explained using FIGS. 14 to 17.

That is, as shown in FIG. 14, the device of this example has a rotor provided with a rotating shaft 1 as a driving shaft, a shaft-side bobbin 15 and 2 fixed to the rotating shaft 1, and a rotating shaft 2 as a driven shaft (FIG. 15). 22, a detection coil 33 provided between the shaft-side bobbin 15 and the rotor 22, a metal core 34, and the like.

Further, the shaft-side bobbin 15 has a χ
, Ky are wound, and the capacitors 59 and 59 are fixed. The solenoid coils 50 and 51 include the input coil 65.
．． Output coils 75 are arranged facing each other (Fig. 14, the sixth
(see figure).

Regarding the detection coil and the metal core, as shown in FIGS.
Detection coils 31 and 33 are disposed at 6, and metal cores 32 and 34 are disposed on a fixed frame 25 provided on the rotor 22 side. The detection coils 31, 33 are installed in the through hole 161 of the fixture 16, as shown in FIGS. 1 and 2 above.

As shown in FIG. 14, the metal core 34 has both ends of its shaft 343 movably supported by the fixed frame 25. One end of the shaft 343 is screwed onto the fixed frame 25. Therefore, the position adjustment for zero point adjustment is performed by rotating the screw head 347 of the shaft 343 and moving the metal core 34 from side to side. The same applies to the metal core 32.

In addition, between the rotating shaft 1 and the rotating shaft 2, there is a
As shown in Figure 7, a glue spring 1 is used as an elastic body.
Interpose 01. A stopper 24 is disposed in the cutout hole 26 of the rotating shaft 2 between it and the rotating shaft 1 so that the maximum rotation angle does not exceed 6 degrees. Furthermore, the rotor 22 is connected to the rotating shaft 2 via a retainer 23. Also, rotor 2
A rotor hair ring 221 is interposed between 2 and the rotating shaft 1.

When rotational torque is generated between the two rotating shafts 1 and 2, the detection coil 31.
A positional change occurs between the metal cores 32 and 33 and the metal cores 32 and 34, and one rotation torque can be detected.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 9 show a first embodiment of the present invention.
2 and 2 are exploded perspective views of the sensor section. 3 and 4 are explanatory diagrams showing the rotation angle difference of the detection coil, FIG. 5 is a conceptual diagram of the torque detection device, FIG. 6 is a layout diagram of the detection section, FIG. 7 is an oscillation circuit diagram, and FIG. 8 and 9 are diagrams showing the relationship between angular displacement and oscillation frequency or difference in oscillation frequency, FIGS. 10 to 13 show the second embodiment, and FIGS. Side view of detection coil, first
2 and 13 are diagrams showing the relationship between angular displacement and oscillation frequency or difference in oscillation frequency, FIGS. 14 to 17 show the torque detection device of the third embodiment, and FIG. 14 is a perspective view thereof. ,
15 is a sectional view thereof, FIG. 16 is a sectional view taken along the line FF in FIG. 15, FIG. 17 is a sectional view of the main part taken along the line GG in FIG. The figure is an explanatory diagram of the metal core, the second
Figure 0 is an explanatory diagram of the detection coil, Figures 21 and 22 are wire circuits showing the relationship between the dimensions of the metal core and sensitivity, and Figures 23 and 24 are conceptual diagrams showing a conventional torque detection device. be. 1.2...Rotation axis. 10...Elastic body. 101...leaf spring. 31.33...Detection coil. 32.34. ,,metal core. 321.341,342... Core portion 50.51... Solenoid coil 59... Capacitor 65... Input coil. 75... Output coils Jx, Jy, . . . Sensor section Kx Kyoo, LC series circuit Lx Ly, . . . Detection section Nx, Ny, . . . Waveform shaping circuit.

Claims (1)

[Claims] (1) An annular detection coil without a bobbin is arranged on the rotating shaft that receives rotational torque, and a metal core that does not have ferromagnetism is arranged, and when the rotating shaft is twisted by the torque, the metal core moves back and forth within the cavity of the detection coil so that the inductance of the detection coil changes in response to the difference in rotation angle, and two sets of the detection coil and metal core are arranged, and one metal core has one metal core. The other metal core has two core parts, and a capacitor and a solenoid coil wound around the rotating shaft are connected in series and fixed on the rotating shaft, and the above-mentioned detection A coil, a capacitor, and a solenoid coil are connected in series to form a resonant circuit, and a detection unit is provided, which includes an input coil and an output coil each consisting of a magnetic core and a coil wound around the core. The input coil and the output coil are disposed on both sides of the rotating shaft, facing the solenoid coil, with a gap between them, and the resonant circuit and the detection section constitute an oscillation circuit that oscillates at the resonant frequency of the resonant circuit, and generates a torque. A torque detection device for a rotating shaft, characterized in that a rotation angle difference corresponding to the rotation angle is detected as a change in oscillation frequency.