JPH02145935A - Torque detector - Google Patents

Abstract

PURPOSE:To enable an inexpensive and stable measurement of a torque with limited power in a non-contact manner by comparing an AC signal and a detection signal of a secondary signal converted therefrom to detect a Barkhausen noise component. CONSTITUTION:A high frequency signal produced with a high frequency oscillation circuit 3 is amplified 4 up to a proper power and then, supplied to an exciting coil 22 of a sensor 2 as detector. Then, a rotating shaft 1 to be measured having a ferromagnetic characteristic is excited with the coil 22 and with the excitation thereof, a magnetic reaction is generated in the rotating shaft 1 in a secondary way. This reaction is detected by a detection coil 24, a detection signal of which is amplified 6 up to a proper value and then, a processing is performed by a detection signal processing circuit 7 to remove an undesired noise component. Then, a high frequency signal as source oscillation signal is removed by a processing with a comparative computation circuit 8 to leave a Barkhausen noise component generated by a torque. Then, a level of the component is converted into a level of a torque component with a torque value conversion calculation circuit 9 to be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a torque detection device suitable for measuring the torque of a rotating shaft in a transportation machine, an industrial machine, a construction machine, or the like.

[Prior Art] Conventionally, in order to detect the torque transmitted by a rotating shaft, the torque of the rotating shaft is calculated from the rotational speed of the rotating shaft and the amount of strain measured by a strain gauge bonded to the rotating shaft. When a high-frequency magnetic field is applied to the rotating shaft, the magnetic flux density of the rotating shaft changes due to the magnetostrictive phenomenon in which the magnetic permeability of the rotating shaft, which is a magnetic material, changes due to the internal stress generated due to the torque transmitted by the rotating shaft. A method was used to detect this using a detection coil.

Fig. 4 shows a method using a strain gauge. In Fig. 0, 13 is the rotating shaft of the object to be measured, 31 is a strain gauge glued to the rotating shaft, and wiring is omitted.
2 is a circuit component for connecting the strain gauge to an off-axis circuit, and a slip ring or a wireless transmission circuit is used. In the case of a wireless transmission circuit, the rotating shaft side includes an oscillation circuit, an amplifier circuit, a balance detection circuit, a modulation circuit, a transmitting circuit, a battery, and a transmitting antenna necessary for the bridge circuit for the strain gauge, and is opposite to the transmitting antenna. The external circuitry includes a receiving antenna and an amplifier circuit. 33
is a signal processing circuit, which includes a demodulation circuit and an amplification circuit when a wireless transmission circuit is used for 32, and an oscillation circuit as a power source for the strain gauge and an oscillation circuit as a power source for the strain gauge when a slithering ring is used for 32. It includes a bridge circuit, a balance detection circuit, etc. for collecting deviation signals. A resistance change caused by strain in the strain gauge is detected from the bridge circuit including the strain gauge described above and transmitted to a fixed arithmetic circuit 36. 34 is a rotation sensor for detecting the rotational speed of the shaft, and 35
is a signal processing circuit that is designed according to the type of sensor and converts the sensor detection signal into a signal suitable for calculation processing in the next stage calculation circuit 36. The arithmetic circuit 36 calculates the magnitude of the torque from the above-mentioned amount of distortion occurring in the rotating shaft and the rotational speed of the rotating shaft.

FIG. 5 shows a circuit that detects torque by utilizing the magnetostriction phenomenon, where 14 is the rotating shaft to be measured, 4O is an oscillation circuit for excitation, and the oscillation signal is sent to the amplifier circuit 41 to generate the necessary power. After being amplified, it is supplied to the excitation coil 42. After the detection coil 43 detects the magnetic flux that is generated secondarily according to the magnetic permeability of the rotating shaft 14 due to the magnetic field created by the excitation coil 42, the electronic circuit 44 amplifies the detection signal, and then the arithmetic processing circuit 45 generates oscillation. The torque is calculated using a table relating to the ratio of the output to the received signal level, and the internal stress and magnetostrictive characteristics of the rotating shaft that have been calibrated and recorded in advance.

[Problem M to be solved by the invention] However, in the above-mentioned conventional measurement means using a strain gauge, special methods such as using a slip ring or transmitting as a wireless signal in order to extract the measured value from the rotating shaft from the rotating object to the outside. However, since the component circuit is complicated, there are problems such as noise being superimposed, signal level drift, and high cost. This method requires a large amount of power at different frequencies, and the applied power increases the temperature of the detection sensor, causing problems such as drifting of measured values.

The present invention has focused on the above-mentioned conventional problems, and aims to provide an inexpensive and stable method for measuring the torque of a rotating shaft.9 [Means for Solving the Problems] The present invention solves the problem and improves the conventional torque detection method, and includes an AC signal source, an excitation coil for exciting a rotating shaft to be measured by the AC signal, and a coil that secondarily activates the rotating shaft by the excitation. and a detection coil for detecting the generated magnetic reaction, and is configured to compare the alternating current signal and the detection signal and detect the torque being applied to the rotating shaft to be measured from the Barkhausen noise component included in the detection signal. It is an object of the present invention to provide a torque detection device for a rotating shaft having ferromagnetic characteristics.

According to the above configuration, the AC signal source, the excitation coil for exciting the rotating shaft to be measured by the AC signal, and the detection coil for detecting the secondary signal converted at the rotating shaft. Since the Barkhausen noise component included in the detection signal is detected by comparing the AC signal and the detection signal, the relative angle between the rotating shaft and the detection coil can be determined without contacting the rotating shaft. This makes it possible to measure torque with small electric power without being affected by

Embodiments] Hereinafter, embodiments of the torque detection device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of a circuit of a torque detection device, and FIG. 2 is a sectional view of a sensor section of the torque detection device. FIG. 3 is a characteristic diagram showing an example of the relationship between the stress occurring in the measured axis and the measured value of Barkhausen noise.

In the figure, 1 should measure torque:! 2 is a sensor, 3 is an oscillation circuit for high-frequency signals for measurement, 4 is an amplifier circuit, 5 is a signal processing circuit, 6 is an amplifier circuit,
7 is a detection signal processing circuit, 8 is a comparison calculation circuit, 9 is a torque value conversion calculation circuit, 21 is an excitation core, 22 is an excitation coil, 23 is a detection core, 24 is a detection coil, and 25 is a shielding case. It is the body.

In the drawing, the lead wires of the excitation and detection coils are omitted.

Next, the operation of this embodiment will be explained. When the rotating shaft 1 is used in an industrial machine, it is generally made of iron and has ferromagnetic properties. However, in the case of a rotating shaft made of other materials, Ferromagnetic properties are added to the surface of the shaft by pasting or plating a thin plate of ferromagnetic material.

The high frequency signal generated by the high frequency oscillation circuit 2 is transmitted to the amplifier circuit 4.
After the power is amplified to an appropriate power, it is supplied to the excitation coil of the sensor 2. The rotating shaft, which is a ferromagnetic material that generates internal stress due to torque, or the ferromagnetic material provided on the surface of the rotating shaft, generates Barkhausen noise determined by the characteristics of the material depending on the relationship between the stress and the magnetic field, and the detection coil 24 It is detected as a signal superimposed on the high frequency signal excited by the The signal detected by the detection coil 24 is amplified to an appropriate value by the amplifier circuit 6, and then processed by the detection signal processing circuit to remove unnecessary noise components, and then processed by the comparison calculation circuit 8 to a subtraction circuit, for example. The high-frequency signal component, which is the source oscillation signal, is removed while leaving the Barkhausen noise component. The high-frequency signal generated by the high-frequency oscillation circuit 3 before being supplied to the comparison calculation circuit 8 is subjected to a phase shift, for example, to match the phase with the detection signal in order to make it an appropriate signal for processing by the comparison calculation circuit 8. After being processed, it is supplied to a comparison calculation circuit. The Barkhausen noise collected from the comparison calculation circuit is stored in advance in a characteristic table prepared by measuring the characteristics of the ferromagnetic material or rotating shaft, such as the data shown in Figure 3. A torque value conversion calculation circuit converts the level of the Barkhausen noise component into the level of the torque component and outputs the result. The comparison calculation circuit 8 may be any circuit as long as it is a circuit for removing the high frequency signal which is the fundamental wave from the signal detected from the detection coil.Therefore, the contents of the signal processing circuit 5 and the detection signal processing circuit 7 are as follows. An appropriate circuit is designed according to the characteristics of the comparison operation circuit.

[Effects of the Invention] As explained above, according to the present invention, an AC signal source,
An excitation coil for exciting the rotating shaft to be measured by the alternating current signal, and a detection coil for detecting a secondary signal converted at the rotating shaft, and detection by comparing the alternating current signal and the detection signal. Since it detects the Barkhausen noise component included in the signal, it is possible to measure torque with less power without contacting the rotating shaft, making it possible to measure the torque of the rotating shaft inexpensively and stably. Became.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of an embodiment of a torque detection device according to an embodiment. FIG. 2 is a cross-sectional view of a sensor portion of the embodiment of the torque detection device according to the embodiment. 3rd UA is an example diagram of Barkhausen noise/torque calibration characteristics of the torque detection device according to the embodiment. FIG. 4 is a circuit configuration diagram of an example of a conventional torque detection device. FIG. 5 is a circuit diagram of another example of a conventional torque detection device. 1...Rotary axis to be measured 2...Sensor 3...Oscillation circuit 4...Amplification circuit 5...Signal processing circuit 6... ... Amplification circuit 7 ... Detection signal processing circuit 8 ... Comparison calculation circuit 9 ... Torque value conversion calculation circuit 13 ... Rotating shaft to be measured 14 ...・Measurement rotating shaft 21...Excitation core 22...Excitation coil 3...Detection core 4...Detection coil 5...・・Shielded・・・Strength gauge 32・・・Slip ring/wireless transmission circuit 33・
... Signal processing circuit 4 ... Rotation sensor 5 ... Signal processing area 6 ... Arithmetic circuit 0 ... Oscillation circuit 1 ... ...Amplification circuit 2...Excitation coil 3...Detection coil 4...Electronic circuit 5...Arithmetic processing circuit

Claims (1)

[Claims] An alternating current signal source, an excitation coil for exciting a rotating shaft to be measured having ferromagnetic characteristics with the alternating current signal, and a detection coil for detecting a magnetic reaction secondarily generated in the rotating shaft due to the excitation. The alternating current signal component is removed from the detection signal obtained by the detection coil, and the amount of torque transmitted by the rotating shaft to be measured is detected and measured by the Barkhausen noise component included in the detection signal. Rotating shaft torque detection device.