JPH01173844A - Torque measuring instrument - Google Patents

Abstract

PURPOSE:To eliminate the loading of a shaft for correction with torque and to prevent various errors generated at the time of torque detection owing to temperature variation and a secular change from being affected by a torque signal by providing the shaft for correction in addition to a torque transmission shaft and providing this shaft for correction with 1st and 2nd correcting coils. CONSTITUTION:The shaft 55 for correction which is provided with magnetic anisotropic parts 14 and 15 for correction are arranged separately from the shaft 11 provided with magnetic anisotropic parts 12 and 13 for torque detection for torque transmission. Exciting coils 16-19 of the shafts 11 and 55 are connected in series and connected to power sources 26 and 27. Further, a CPU 40 is connected to detection coils 20 and 21 of the shaft 11 and correcting coils 22 and 23 of the shaft 55 through rectifiers 28-31 and A/D converters 36-39. Then a reference value setting device 47 and manual switches 50-52 are connected to the CPU 40 and various errors are corrected excellently without being affected by a torque signal generated by the shaft 55 at the time of the torque detection.

Description

[Detailed description of the invention] Industrial applications TECHNICAL FIELD The present invention relates to a torque measuring device, particularly for engines.

The present invention relates to a torque measuring device that can non-contactly measure the torque of motors, industrial machine drive shafts, etc.

2. Prior Art A conventional torque measuring device of this type is the patent No. 1693.
There is something disclosed in the specification of No. 26. This is the 10th
As shown in the figure, a knurling part 2.3 is formed on the outer periphery of a shaft 1 having ferromagnetism and magnetostriction, and is inclined in opposite directions at an angle of 45 degrees with the direction of the axis of rotation of this shaft 1.
An excitation coil 4 is formed on the outer periphery of each knurling part 2.3.
and a detection coil 5°6 are respectively arranged.

According to such a configuration, magnetic anisotropy is imparted by the knurling portions 2, 3, and changes in magnetic permeability in each knurling portion 2.3 based on the transmitted torque are detected by the detection coil 5.6. At this time, since the knurling parts 2 and 3 are inclined in opposite directions, when a compressive force is applied in one knurling direction, a tensile force is applied in the other knurling direction. Therefore, as shown in FIG.
The detection voltage 7 of one of the coils 6 increases as the torque increases, while the detection voltage 8 of the other coil decreases. Here, when the difference between the detected voltage 7 of one coil and the detected voltage 8 of the other coil is taken and combined, a torque detected voltage 9 indicating only a change in torque is obtained as shown in FIG. 12.

In addition, as another conventional torque detection device,
There is one shown in Japanese Patent No. 166827. In this case, in place of the knurling portion in FIG. 10, amorphous ferromagnetic layers tilted in opposite directions are similarly formed on the surface of the rotating shaft by adhesion, plating, or other means.

According to such a device, torque can be measured even for a shaft that does not have ferromagnetism.

Problems to be Solved by the Invention However, in such conventional devices, the balance of the detection voltage 7.8 output from the rain detection coil 5゜6 when no transmission torque is applied is affected by temperature changes and aging. It tends to change due to changes. This is due to changes in the magnetism (magnetic permeability, magnetostriction) in the axial direction of the shaft 1, changes in iron loss due to lines of magnetic force penetrating the shaft, and changes in the excitation coil 4, detection coils 5 and 6, etc. This is due to variations in materials such as the magnetic layer of shaft 1 and in manufacturing. As a result, the zero point of the detection voltage 7.8 in FIG. 11 changes, and a phenomenon occurs in which the point of intersection between the two shifts from the vertical axis to the side, causing an error in the measured torque value.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and to prevent errors from occurring in torque measurement values due to changes in the balance, zero point, and sensitivity.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a structure in which the magnetic anisotropy is imparted by tilting in mutually opposite directions at an angle with the direction of the rotational axis of the torque transmission shaft. The torque detecting section includes first and second magnetic anisotropic sections for torque detection, and first and second detection coils capable of detecting changes in magnetic permeability in each magnetic anisotropic section for torque detection. and a correction shaft that is different from the torque transmission shaft and is not subjected to a torque load, and an outer periphery of the correction shaft that is inclined in opposite directions at an angle with the direction of the axis of the correction shaft. The correction unit includes first and second correction magnetic anisotropy parts formed on the surface and first and second correction coils provided around each correction magnetic anisotropy part. However, the correction section is configured to have substantially the same magnetic characteristics as the torque detection section, and is arranged near the torque detection section.

Effect: According to such a configuration, the correction shaft is not loaded with a useless torque that is provided separately from the torque transmission shaft. Therefore, by detecting the outputs of both correction coils and controlling the excitation side AC power supply so as to keep this detected voltage constant, each @ error that occurs during torque detection based on temperature changes and secular changes can be reduced to Correction is made with almost no influence from the signal.

Embodiment In FIG. 2, reference numeral 11 denotes a torque transmission shaft, which is used, for example, to transmit the output of an engine to a working device. On the outer peripheral surface of the shaft 11, there is formed an angle of 20 to 60 degrees, preferably 45 degrees with the direction of the rotational axis of the shaft 11,
Torque detection magnetic anisotropic parts 12 and 13, which are formed to be inclined in opposite directions, are provided at a predetermined distance from each other. This torque detection magnetic anisotropy section 12.
13 can be formed, for example, by knurling the outer circumferential surface of the shaft 11, as described above, or by attaching or plating an amorphous ferromagnetic layer to the surface of the shaft 11.

A correction shaft 55 that does not receive torque transmission is provided near the shaft 11 at a position that is subjected to approximately the same ambient conditions as the shaft 11, such as temperature. Axis 55 for this correction
Similar to the torque detection magnetic anisotropic portion 12.13 in the shaft 11, the outer circumferential surface of the
Correcting magnetic anisotropic portions 14,15 are formed which are inclined in opposite directions at an angle of ~60 degrees, preferably 45 degrees.

Excitation coils 16.17.18.19 are arranged around the outer periphery of each magnetic anisotropic section 12.13.14.15, respectively. Further, on the outer periphery of each excitation coil 16, 17, 18, 19, there are a detection coil 20.21 corresponding to the magnetic anisotropy section 12.13 for torque detection, and a magnetic anisotropy section 1 for correction.
Correction coils 22 and 23 corresponding to 4°15 are provided, respectively. 24.54 is a core formed of a ferromagnetic material and constitutes a path for magnetic flux, and also serves as a core for each coil 16.54. ...23 is used as a casing for accommodating it. The torque detection section around the shaft 11 and the correction section around the shaft 55 are manufactured so as to have substantially the same magnetic characteristics by, for example, making the characteristics of the magnetic anisotropic portions the same.

FIG. 1 shows the overall configuration of this device including an electronic circuit. In the figure, 25 is an oscillator, and this oscillator 25 has:
First and second AC power sources 26 and 27 each composed of a power amplifier are connected.

The excitation coils 16 and 18 are connected in series to the first power source 2.
6 and the excitation coil 17.19 is connected to the second power supply 27, also connected in series. The detection coil 20.21 and the correction coil 22.23 each include a rectifier 28.29.30.31 and a filter 32.33.34.3 composed of a resistor and a capacitor.
5 and AD converter 38, 39, 36, 37,
It is connected to CPU 40.

A power cutoff signal @41 for cutting off the outputs of both type sources 26 and 27 is connected to the CPU 40 together with an OA converter 42 . Also connected to the CPU 40 are power supply control signal lines 43 and 44 that adjust the amplification factors of the power amplifiers constituting the dual-type power sources 26 and 27 to adjust their outputs. 45.46 is each signal line 4
This is an OA converter installed in 3.44. 47 is a reference value setting device, which sets the reference value Es set digitally or by software using the internal memory of the CP port.
l Enter into 40. A timing setting device 48 is also connected to the CPU 40 and sets the operation timing for this circuit. 49 is a torque signal output terminal. Manual switches 50, 51, and 52 are used to correct various errors at any time regardless of the operation timing of this circuit.

Next, the operation based on the above configuration will be explained. Power supply 26.
27, output voltages appear in the detection coil 20.21 and correction coil 22.23, and each voltage is
Output side of converter 38, 39, 36, 37, that is, CPU
On the input side of 40, Vt, V2, St
.

The value becomes δ2. Further, these values are subjected to arithmetic processing as described later in the CPU 40, and each value is Vt'
, V2', St', 82'.

When torque acts on the shaft 11, the output voltage of the detection coils 20 and 21 is
The result shown in FIG. 3 is obtained. These values V1. V
2 is arithmetic processed inside the CPU 40 and converted into values V1' and V2' as described later, and the value k (V1
'-V2') is output from the output terminal 49 as a torque signal. FIG. 4 shows the output voltage V1. of FIG. An example of a torque signal T based on V2 is shown.

Errors caused by changes in humidity or changes over time are corrected as follows. Note that both shafts 11.55 are located close to each other, and the temperature conditions around these two wheels 11.55 are considered to be substantially the same.

First, zero point correction is performed. In this case, the outputs of both type sources 26 and 27 are cut off via the power cutoff signal line 41. Then, since the excitation voltage of each excitation coil 16, 17, 18, 19 becomes O, the corresponding detection coil 2
0.21 and the output voltage of the correction coil 22.23 should also be O. Therefore, at this time, each AD converter 3
8.39.36.37 output is a value other than O, for example ■
1-ε1. V2-ε2. If S1-δ1°δ2-δ2, this is due to some error, such as temperature drift of the electronic circuit or other changes. Therefore, the CPU 40 executes V1'-Vt-δ1. V2'-
V2-δ2゜S1'-81-61,82' =82-
Perform aSS processing so that the value becomes 62. This causes the power supply 26.
When 27 is shut off, V1'-V2' = 81' -8
2' = O, and even after the power supply 26.27 is restored, the above ε1. δ2. δ1.
Data V1' for which zero point correction has been completed by holding δ2
.

Use V2', St', and 82'.

Next, balance correction is performed between the rain detection section and both correction sections. In other words, if the magnetic properties of the torque detection magnetic anisotropic portion 12.13 change due to temperature changes, the detection voltage V1゜■2 will become as shown in Fig. 5 even when the torque is zero, and the corresponding The torque signal T thus generated also varies from the normal state as shown in FIG. 6, so this is corrected.

For this purpose, a correction voltage S1°δ is set inside the CPU 40.
2 correction data S1', 82' difference S1'-82'
Calculate. Then, via the power control signal line 43,
A control signal is sent to the second power supply 27, and S1'-82'
The power supply 27 is adjusted so that =O. By doing this, the excitation voltages of the excitation coils 17 and 19 connected in series are adjusted at the same time, the output S2 and the output ■2 are corrected accordingly, and the balance between Sl and 82, that is, between ■1 and ■The balance with 2 is corrected. in this case,
It is assumed that similar changes occur depending on the magnetic properties of the magnetic anisotropic portion of the shaft 55 and temperature. As a result, the characteristic diagrams shown in FIGS. 5 and 6 are corrected to the states shown in FIGS. 3 and 4.

Next, sensitivity correction is performed. That is, at the stage where the above-mentioned balance correction has been performed, both signals V
1' and V2', the left and right image characteristics are almost controlled and maintained around torque 0, but the level Em fluctuates up and down depending on the temperature. When a temperature change occurs, both signals V1',
The slope of V2' changes as Em changes, and as shown in FIG. 8, the dotted line characteristic becomes the solid line characteristic. As a result, the slope of the torque output signal line represented by k(Vt'-V2') (see FIG. 4) changes, and the measurement sensitivity changes.

Therefore, correction is performed so that the average value E of both signals V1' and V2' is returned to a predetermined value and its slope is set to a predetermined value so that the sensitivity characteristics become constant.

Here, the sum of both signals V1' is used as a value representing the average value.
+V2' (a value twice the average value E) is used. This value is set equal to the set value Es input to the CPU 40 by the reference value setting Kr1147, that is, (V1' +
V2')-Es=O. Specifically, both layers are connected by power supply control signal @ffJ44! I26.
27 at the same ratio and increase/decrease their output levels at the same time, without changing the balance at the rain detection position.
V1'+V2' is controlled to be equal to Es. When the output levels of both signals Vz' and V2' are returned to the predetermined values in this way, the characteristics shown by the solid line return to those shown by the dotted line, as shown in FIG. This completes the sensitivity correction.

By changing the reference set value Es, the measurement sensitivity of the present device can be varied in various ways, thereby making it possible to obtain a wide variety of measurement ranges.

The above-described zero point correction, balance correction, and sensitivity correction are performed in this order at a constant timing by the timing circuit 48. That is, for example, as shown in FIG.
The cycle is set to 1 minute, zero correction is performed in the first 50 milliseconds, balance correction is performed in the next 50 milliseconds, and sensitivity correction is performed constantly, that is, many times, within the remaining time.
Such a cycle is repeatedly executed. Note that during the zero point correction and balance correction operations, the torque detection output signal immediately before correction is held and output from the terminal 49.

In addition to such automatic cycle operations, manual corrections can be made at any time.

For example, manual switch 50 for zero point correction
When the switch 50 is operated, the signal is taken into the CP IJ 40, and the above-described zero point correction operation is repeatedly executed while the switch 50 is operated. When the switch operation is completed, the torque measurement value k (V1'-
V2') is output.

When the manual switch 51 for balance correction is pressed, the above-described balance correction operation is executed.

Such manual operation is normally performed under the condition shown in Figure 6, that is, even though no torque load is applied.
The detection status on both sides is unbalanced and the torque indication value is O.
This is often done when the situation is not met.

When performing manual correction using the manual switch 52 for sensitivity correction, for example, when the production of this device is completed, apply a rated torque to the shaft 11 using a weight, etc., so that the indicated value at that time matches the rated value. Reference value setting @
Just adjust @47.

As described above, according to the present device, almost all of the various errors such as temperature change, aging change, and zero point change in the torque output signal can be automatically corrected. In particular, sensitivity changes and zero point changes due to temperature changes can be automatically corrected regardless of the presence or absence of torque load. In addition, the electronic processing circuit includes an AD converter 36.37
．． 38, 39 and the DA converters 42, 45, 46, the configuration can be simple in that only the CP LJ 40 is present. This is also due to the fact that various errors were automatically corrected using software.

Effects of the Invention As described above, according to the present invention, a torque detection section is provided corresponding to the axis on which torque acts, and a correction section is provided on the correction axis on which no torque acts, so that temperature changes, aging, etc. Based on this, it is possible to satisfactorily correct various errors that occur during torque detection, making it possible to perform highly accurate torque detection.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the torque measuring device of the present invention;
Figure 2 is a configuration diagram around the axis in Figure 1, Figure 3 is a characteristic diagram showing the detected voltage when there is no error, and Figure 4 is a characteristic diagram showing the torque detection voltage based on Figure 3. 5
The figure is a characteristic diagram showing the torque detection voltage when balance is lost, Figure 6 is a characteristic diagram showing the torque detection voltage based on Figure 5, and Figure 7 is a characteristic diagram showing the torque detection voltage under a predetermined sensitivity. Figure 8 is a characteristic diagram showing the torque detection voltage when the sensitivity fluctuates; Figure 9 is an operation timing diagram of the circuit shown in Figure 1; Figure 10 is a schematic diagram of a conventional torque measuring device; FIG. 11 is a characteristic diagram showing the detected voltage in the apparatus of FIG. 10, and FIG. 12 is a characteristic diagram showing the torque detection voltage based on FIG. 11... Axis, 12.13... Magnetic anisotropic part for torque detection, 14, 15... Magnetic anisotropic part for correction, 16.1
7.18.19... Excitation coil, 20.21... Detection coil, 22.23... Correction coil, 26.27.
...AC power supply, 40...CPLI, 47...Standard U
Ii setting device, 50.51.52...manual switch, 55...axis for correction. Agent Yoshihiro Morimoto Fig. 1 55 - Nezo El/) Fig. 2 te > tu i-t Z/ Fig. 3
Figure 5 Figure 4 Figure 6 Figure 8 Figure 9

Claims (1)

[Scope of Claims] 1. First and second magnetic anisotropy for torque detection formed at an angle with the direction of the rotational axis of the torque transmission shaft and tilted in opposite directions to each other and provided with magnetic anisotropy. and first and second detection coils capable of detecting a change in magnetic permeability in each torque detection magnetic anisotropic section, a first and second correction shaft formed on the outer circumferential surface of the correction shaft so as to form an angle with the direction of the axis of the correction shaft and to be inclined in opposite directions; It has a correction section including a magnetic anisotropy section and first and second correction coils provided around each correction magnetic anisotropy section, and the correction section is located approximately at a distance from the torque detection section. A torque measuring device characterized in that the device is configured to have the same magnetic characteristics and is provided near a torque detecting section. 2. The torque measuring device according to claim 1, wherein the correction section is provided at a location where the temperature and other ambient environmental conditions are substantially the same as those of the torque detection section. 3. An excitation coil is provided for each detection coil and each correction coil, and the excitation coil for the first detection coil and the excitation coil for the first correction coil are connected in series and connected to the first AC power source. According to claim 1, the excitation coil for the second detection coil and the excitation coil for the second correction coil are connected in series and connected to the second AC power source. torque measuring device. 4. Means for cutting off the output of the first and second power supplies at appropriate timing during torque measurement, and first and second detection coils and first and second correction coils when the power supply output is cut off. and means for calibrating the measured data by subtracting the reading of each coil at the time of power cutoff from the measured values of both detection coils and both correction coils when the cutoff of the power output is released. The torque measuring device according to claim 3, characterized in that it has the following. 5. The torque measuring device according to claim 4, further comprising means for adjusting one of the power sources so that the calibration values of the measurement data of both correction coils are equal. 6. The torque according to claim 4 or 5, characterized by having means for adjusting both power supplies so that the sum of the calibration values of the measurement data of both detection coils becomes a constant reference value. measuring device. 7. The torque measuring device according to claim 6, wherein the reference value can be set by a digital reference value setting device. 8. Processing to calibrate the measurement data of both detection coils at fixed timing, processing to adjust the power supply of either one so that the calibration value of the measurement data of both correction coils is equal, and measurement of both detection coils. A process for adjusting both power supplies so that the sum of the calibration values of the data becomes a constant reference value; and a means for executing either one of the following processes or serially executing two or more of the following processes. The torque measuring device according to claim 6 or 7, characterized in that: 9. The device according to claim 8, further comprising a manual switch that allows at least one of the above processes to be executed at any time by manual operation, regardless of the fixed timing. Torque measuring device. 10. According to any one of claims 4 to 9, the sensor has a torque value output terminal that outputs a value obtained by multiplying the difference between the calibration values of the measurement data of both detection coils by a coefficient. torque measuring device.