JPH0228528A - Torque measuring instrument - Google Patents

Abstract

PURPOSE:To accurately measure torque values for every short time by providing plural marking bodies in the shaft direction of a power transmission shaft and calculating an added value of phase differences of outputs from each mark detecting body which are provided in plural numbers around each marking body. CONSTITUTION:The 1st to the 3rd gears 1-3 are firmly attached to a propeller shaft 40 of a ship, and mounting rings for electromagnetic pickups which are partly fixed to the ship body with fixtures 7-9 respectively are provided concentratedly and outwards of each gear 1-3, and on these mounting rings, groups 1n-3n of M pieces of the electromagnetic pickups are fixed respectively with about an equivalent pitch. When the shaft 40 is made to rotate, M pieces of outputs in a sinewave state are produced from the groups 1n-3n of the electromagnetic pickups with respect to each gear 1-3, then each phase of them are changed in accordance with the torques. The measurements for 3M pieces of the phase differences are made at the same time and the added value is obtained accordingly, so the torque values for every short time can be accurately measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that measures torque by converting the torsion angle of an actually operating shaft, such as a screw shut of a ship, into a phase difference.

Supervision! υl side A device of this type is the ``Torque Measuring Device'' published in Japanese Patent Publication No. 53-5828, which has a gear made of magnetic material fixed to two points on the shaft spaced apart in the wheel direction. , a plurality of electromagnetic pickups (hereinafter abbreviated as PU) as mark detection bodies are arranged around the gear, and a composite output signal of the outputs of the surrounding PUs is formed for each gear, and both composite outputs are generated. It is designed to measure the phase difference between signals.

In this case, when the shaft rotates and the gear integrated with it rotates, a substantially sinusoidal voltage output corresponding to the gear tooth profile is generated in each PU, and a composite signal of the PU group for each gear is formed. It is done. When the shaft transmits torque, a torsion angle occurs in the pongee that is proportional to the magnitude of the torque, and as a result,
The relative position in the rotational direction between the two gears changes, which changes the phase of the PU output. Therefore, for example, the phase difference between the combined outputs of each PU group provided for the two gears is Torque is determined by measuring with clock pulses.

However, in this case, even if a relative displacement occurs in the axial cross-sectional direction between the pongee and the PU, and as a result, a phase change unrelated to the small output torque of each PU occurs, when looking at the entire PU group, the phase Since the changes include both advances and lags based on geometric relationships, cancellation is performed by synthesis, and only the phase change corresponding to the torque can be extracted.

Problems to be Solved by the Invention Incidentally, torque is not only measured as an average value over a relatively long period of time, but also measured at short intervals for the purpose of determining transient behavior.
Furthermore, it is required to measure values close to instantaneous values such as each rotation of gear tooth pitch.

In this case, the problems are the tooth pitch error of the gear and the asynchrony error between the phase difference gate and the clock pulse when measuring the phase difference. As shown in Figure 3, if there is a tooth pitch error, two PUs will come out even if the shaft rotates steadily.

The phase difference of the mouth opening fluctuates. Furthermore, when measuring the phase difference C, quantization is performed by interpolating the clock pulse, but since the phase difference and the clock pulse are asynchronous at the start and end points of the phase difference date, the associated error can be avoided. I can't do it.

Among these, the pitch error of the gear can be canceled out by increasing the number of PUs arranged around the gear, and may be increased as appropriate. On the other hand, regarding the asynchronous error, it is possible to increase the frequency of the interpolated clock pulse and reduce the weight of the asynchronous error, but even if this is done, the number of interpolated clock pulses during high-speed rotation is limited. It was difficult to obtain accurate measurements over the entire range from low to high speeds.

An object of the present invention is to obtain a measuring device that is less affected by asynchronous errors even when measuring torque at relatively short intervals.

In order to solve the above problems, the present invention provides marks that are formed at approximately equal pitches in the circumferential direction at a plurality of different positions in the axial direction of the power transmission shaft. A mark body is provided, a large number of mark detection bodies are arranged around each mark body facing the mark, and the output of each mark detection body is introduced into a phase difference calculator, and each mark detection body is randomly detected on a different mark body. The outputs of the mark detection bodies at selected arbitrary positions are made into pairs, and the phase difference sum of the outputs of each pair is calculated.

The more the marks are provided at different axial positions, the more effective it is, and when the number of marks is 3°4.5..., the output pairs are 3 and 6, respectively, compared to when the number is 2. .10 times.

In more than just the operation, when the shaft rotates and the mark body integral with it rotates, a periodic output corresponding to the mark on the mark body is generated in each mark detection body. Then, the phase difference between arbitrarily selected outputs of mark detection bodies provided for each different mark body is measured by interpolating clock pulses. In other words, let N be the number of mark bodies placed at different positions on the thin soil, M be the number of mark detection bodies placed around each mark body, and use the output of each mark detection body by branching it to the required number. , the number of phase differences required in this case is MN(N-1)/2. Each of these phase differences is affected by the mark pitch error of the mark body, and an asynchronous error occurs during quantization, but
As a result of adding all these quantized phase differences, that is, the phase differences converted into the number of clock pulses, the pitch error and the asynchronous error are canceled out, and these errors are miniaturized.

Embodiment To explain with reference to an embodiment, in FIG. 1, first to third gears 1 to 3 are fixed to a propeller shaft 40 of a ship, and one part is attached to each fixing device. , 8.9, PU mounting rings fixed to the hull are arranged concentrically outside gears 1 to 3, and each mounting ring has a PU (hereinafter referred to as PU) consisting of M electromagnetic pickups. abbreviated)
The groups in, 2n, and 3n are fixed at substantially equal pitches.

Therefore, when the shaft 40 rotates, each gear 1 to 3
The PU group generates M sinusoidal outputs, and the phase of each of them changes depending on the torque.

FIG. 2 shows the phase difference calculators of the PU groups in, 2n, and 3n, and the M outputs of each of the PU groups 1n and 2n are sent to the date control circuit group 50, and each of the PU groups 1n and 3n N outputs are sent to the gate control circuit group 60, each N of the PU groups 2n and 3n.
outputs are respectively introduced into the date control circuit group 70,
Appropriately selected outputs in each gate control circuit group 50 to 70 are paired to form M phase difference date control signals, which are transmitted to each corresponding gate group 80, 90, 10.
0 is introduced at one input end of each of the M dates.

Then, to each of the M other input terminals, M kinds of clock pulses, which are obtained by shifting the clock pulse of the clock pulse generator 5120 by M steps and having mutually different phases, are introduced, and are passed therethrough. The clock pulses are sent to the adder 110 and counted by three corresponding counters within the adder 110 for a measurement time determined by a control unit (not shown), and then the sum of the three counted values is stored in the memory 130.
After being transferred to the memory, the adder 110 is reset to zero and is controlled to start the counting operation again.

Therefore, in this case, 3M phase differences are measured at the same time, and the added value is obtained.In the end, in the conventional technology, the measurement time is lengthened to obtain the added value of 3M phase differences. This means that you will be achieving exactly the same effect in a shorter amount of time.

In the above embodiment, the number of gears is 3, but 2 or 4.5 are fine, and the larger the number, the larger the number of PUs arranged around it. As
Even if the measurement time is short, highly accurate measurement can be performed.

Effects of the Invention As described above, according to the present invention, when the number of mark bodies fixed on the axis is N, and the number of mark detection bodies arranged around each of them is M, the output period of the mark detection bodies is Since MN(N-1)/2 phase differences are added at the same time for each phase difference, a large number of phase differences are averaged in a short period of time to improve errors and accurately measure the torque value for each short period of time. can do.

4,

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a block diagram showing an embodiment of a phase difference calculator into which the output of the one shown in Fig. 1 is introduced, and Fig. 3 shows the output waveform of the conventional one. It is a diagram. 1.2.3: Gear in, 2 n, 3 n: Gunyama Ganto of the pickup

Claims (1)

[Claims] 1. Mark bodies with marks formed at approximately equal pitches in the circumferential direction are provided at a plurality of different positions in the axial direction of the power transmission shaft, and a large number of mark detection bodies are arranged around each mark body to face the marks. The output of each mark detection object is introduced into a phase difference calculator, and the output of each randomly selected mark detection object at an arbitrary position on a different mark object is made into a pair, and the phase difference sum value of the output of each pair is calculated. A torque measuring device designed to calculate .