RU2107271C1 - Method of measuring of twisting angle of shaft twisted by torque action with use of nonius scale and with shaft rotating continuously - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: method uses rectangular, electric, count, and nonius pulses the number of which differs by one pulse for one full turn of shaft because of difference in number of teeth of count and nonius gears. This forms electric Nonius scale. When teeth of count and nonius gears cross geometrical axes of pulse pickups the axes of which are positioned in plane passing through geometrical axis of shaft being twisted, initial pulses are formed which are converted to count and nonius pulses by means of formers. Pickups and gears, respectively, are positioned over the length of twisted shaft. If shaft twisting angle equals zero, zero tooth of count gear coincides with nonius gear tooth in profile. Count and nonius pulses are formed simultaneously, and coincidence of pulses occurs on this ordinal number of count gear tooth taken for zero one during assembly. When shaft twisting angle increases pulses coincide on other ordinal number of count gear tooth. Measuring pulses are formed by multiplying the pulse repetition frequency of count pickup and summed up for shaft turn period beginning with zero count pulse till next count pulse coincides with nonius pulse. In this case sum of measuring pulses is in direct proportion to shaft twisting angle, and it does not depend on shaft rotary speed. EFFECT: higher measurement results. 6 dwg

Description

 The invention relates to measuring equipment and can be used to measure or control the torque in installations with significant available and consumed powers, for example, on sea vessels for measuring torque on the shafts of propellers, on the shafts of rolling metallurgical mills, on the shafts of the rotor of the helicopter, on the shaft of the gas pumping unit, on the shaft of the gearbox of a turbo-propeller aircraft engine, etc.

 The methods for measuring torque described in the technical literature are reduced to measuring the phase shift of two voltages generated by two generators.

 In known devices (regardless of the use of induction or capacitive sensors), two voltages that are phase shifted in phase are formed, which is measured as the phase shift of two voltages proportional to the actual torque.

 The invention is among the pioneering ones, since it first describes a method for measuring torque in a purely digital form, starting from sensors of generated signals in digital form (in digital form) and ending with the type of output information in the form of a single code. For the first time, the use of the properties of Nonius scales on rotating shafts (parts) is described, which makes it possible to transform without loss a small measurable angle of twist of the shaft into a significant angle at which the pulses coincide, which is measured digitally by the sum of the number of pulses.

The purpose of the invention is to provide increased accuracy of the measurement of torque (M _cr ), and therefore in increased accuracy of measuring the mechanical power transmitted by the shaft from the power source to the consumer with an instrument error of no worse than 0.25% of the maximum measured value, in addition, the invention aims to provide the product control system with digital information about the current value of the torque level M _cr , for example, in the form of a single code.

 The invention provides the possibility of conducting an end-to-end check of the technical condition of the whole system without the use of external control systems, and also when debugging a torque meter, it provides an instrument way to correct technological inaccuracies and tolerances for manufacturing parts and assembling the product in order to eliminate these inaccuracies at the final stage assembly.

In FIG. 1 shows the interrelated elements that provide the sequence and conditions for the action of the method of measuring the angle of rotation of the shaft, where 1 is the power source, 2 is the power consumer, 3 is the measuring shaft (O ₁ - O ₂ ), 4 is the counting gear, 5 is the vernier gear, 6 - counting sensor (D _sc ), 7 - nonius sensor (D _non ), 8 - zero pulse sensor (D ₀ ), 9 - control inductor (disk), 10 - calculator of the nonius digital torque meter.

A speed sensor with a disk inductor 9 is installed on the shaft from the side of the power source. The inductor disk has one cavity, which provides one initial impulse And ₀ for one revolution of the shaft. This impulse And ₀ permits the beginning of measurement actions in one every completed revolution of the shaft, it also resets (resets) the calculator circuit 10 upon completion of a full revolution of the shaft. The depression on the inductor disk is shifted ahead of the shaft in the angular direction of rotation of the shaft relative to the “zero” tooth of the sensor D _cf , taking into account the direction of rotation of the shaft in the direction of arrow n, for example, by 1/8 ± 20% of the pitch of the gear tooth counting sensor D _cf ( Fig. 3).

The sensor D _midrange 6 generates count pulses And _midrange as the teeth pass the gears of the sensor D _midrange . Gear vernier 5 A _non sensor 7 installed at the output end of the shaft by the power of the consumer, the sensor generates a vernier A _non pulses and their _non angularly delay in the rotational direction of the shaft proportional to the twist of the shaft.

 The zero teeth of both gears (they are also the last ones, for example, 0/68 /, 0/69) in the angular direction are aligned according to the conditions of their assembly along the shaft.

At idle shaft speeds in the absence of torque (at M _cr = 0), both zero pulses of the count sensor and the count sensor and the vernier sensor are combined. The remaining pulses, formed as the shaft rotates by other teeth during the passage of the axes of its sensors, do not provide coincidence in the angle of rotation of the shaft. In this case, in the calculator, the coincidence pattern of pulses belonging respectively to the zero teeth of the sensors D _sc , D _non , records the coincidence of pulses and, as a result, the absence of a twist of the shaft with a measurement result of zero is recorded.

 The sequence of actions of the above-described interconnected elements is as follows.

When the shaft rotates, the generated initial impulse - And ₀ resets the circuit and allows access of the pulse count - And _cf to the coincidence circuit in the calculator.

The pulses of the nonius sensor D _non are also fed to this coincidence circuit. With further rotation of the shaft, the matching circuit of the calculator fixes the angle of rotation of the shaft at which the coincidence of I _sc and I _{non occurs} (coincidence angle φ _coincides ), forming a coincidence pulse And _coinc . The coincidence impulse And _coincide stops the counting of the measuring impulses, it also serves as a resolution (command) for issuing the measured number of impulses from the counter to the digital indicator of the calculator. With the next formation of the initial pulse AND _{0 of the} sensor, the calculator circuit is reset, and the next cycle of the shaft is repeated again.

 The cause-and-effect relationship of the means known prior to the priority date (gears, pulse sensors, shaft, electronic devices) is caused by the cause, as such, by the difference in the number of teeth of counting gears and the vernier one tooth. Changing the angle of twist of the shaft changes the serial number of the tooth of the counting gear, and therefore the number of the counting pulse, at which the counting and vernier pulses coincide. In this case, the sum of the measuring pulses from the beginning of the count (from the zero counting pulse) when the shaft is turned to the angle of coincidence is directly proportional to the measured angle. Electronic nodes look for a zero tooth, form the pulse duration, record the coincidence of the pulses, summarize the measuring pulses and, as a technical result, indicate a number directly proportional to the desired angle.

The zero-pulse sensor D ₀ in the angle of rotation of the first forms its own pulse And ₀ , compared with the pulses of the sensors And _non . This impulse And ₀ resets the circuit, entering the control circuit, the control circuit of the sensor of the useful signal of the ATP, the control circuit of the CXX idle counter, and the ten-day indicator circuit.

The following sequence of the angle of rotation of the shaft is carried out by the formation of the pulse of the counting sensor D _SCH . This pulse is converted, formed in FF, FD, acquiring the parameters And _cf. Counting pulses and _cq (first come after AND ₀₎ is input to coincidence circuit CC and CS control circuit. Control circuit according to the first (row) pulse count and _MF, allows access to the input of the measuring pulses CXX idling counter. When the predetermined (technological) capacity of the CXX counter is overflowed, which is set by the external keys K ₁ , K ₂ - K _n during the debugging of the Vernier digital torque meter, the measuring pulses arrive at the input of the counter of the useful signal of the SPS until the coincidence circuit generates a coincidence pulse And _coincides . This impulse And _{coincident with} the control circuit of the control system, is held as a valid signal until the end of the shaft revolution, where the zero impulse And _{0 is} again formed.

The converted impulse And _{non of the} sensor D _non , the zero gear tooth at M _cr > 0, is shifted with a lag in the angle of rotation of the shaft from the impulse And _{cf in} proportion to the angle of rotation of the shaft. Due to the presence of a twist of the shaft θ, the pulses And _c and And _non will be combined (coincide) at a larger angle of rotation of the shaft. This combination (coincidence) is fixed by the coincidence circuit of the SS, with the formation of an impulse And _coinc . The impulse And _coincides , as mentioned above, by the control circuit is converted into a signal and the level of which is held until the end of the revolution by the shaft until the arrival of the next impulse And ₀ .

The coincidence pulse And _coincides (and its signal) in the _control system stops access of the measuring pulses And _ism to the input of the CXX and then to the input of the ATP.

The sum of the measuring pulses And _ism in the counter of the useful signal of the ATP is actually the result of the measurement. The same pulse And _{coincides the ten-} day circuit of the IND indicator into the display mode until the shaft completes the turn, where the newly generated pulse And ₀ will zero the circuit and give permission to the next measurement cycle.

When turning on and off the measuring pulses AND _ISM for summing in SHX, ATP, due to the mismatch of the switching commands in the control system, one or two counting pulses may be lost. In order to reduce the “weight” of the lost pulses and it would be insignificant, specially prepared pulses are summed up (considered) by the frequency multiplier of the measuring pulses of the UCHII.

The angular duration of pulses And _cf , And _non is set by the formers of the angular duration FD ₁ , FD ₂ , using a fixed number of pulses after the multiplier of the pulse repetition rate of the step frequency multiplier - UCHSHI, converting short-term initial pulses And _counting , And _non-starting to angular duration actions δ _у

This method of forming the angular duration δ _for pulses And _cf , And _non allows you to avoid the measurement error in a wide range of shaft speed. The key KP in the pressed position at idle (M _cr = 0) allows you to measure the technological inaccuracy of the installation of the gears of both sensors D _SCH , D _non , arising from the _non -alignment of zero gear teeth and the installation of speed sensors. This measured technological inaccuracy in the process of debugging a vernier digital torque meter in the form of the number of pulses is entered into the CXX idle counter by external keys K ₁ , K ₂ - K _n , and in the operating mode of measurement at M _cr > 0 it does not enter the useful signal counter of the ATP . The key KP during the operation of the product (when M _cr > 0) allows for an end-to-end check of the system’s performance. The difference in the indicator readings at both positions of the key KP corresponds to the dialed value on the keys K ₁ - K _n with technological
debugging a vernier digital torque meter.

An output to the product controller system is provided in the form of a single code by sending series of pulses And _ism each perfect measurement cycle (i.e., every perfect revolution of the shaft), as well as And ₀ pulses.

 To confirm the possibility of carrying out the invention, an example of a method for measuring the angle of rotation of a shaft twisted by the action of torque using the Nonius scale with a continuously rotating shaft on an aircraft engine is given.

 1. The initial data for the calculation.

 Shaft speed (engine speed).

n _min = 4000 rpm; n _max = 9000 rpm

Nominal twist of the shaft with a torque θ = 2 ^° (with a shaft length l = 350 mm).

The required accuracy of measuring torque is not worse than 0.25% of the nominal value of M _cr .

1.1. RPM Sensors
Selected taking into account the characteristics and design features, serially mastered in production, sensors ДЧВ-2500 (2500 Hz - upper range according to T.U.).

 1.2. Pathogens of sensors.

For structural and technological reasons, sensor exciters are involute gears with the number of teeth:
counting gear Z ₁ = 68 teeth
nonius gear Z ₂ = Z ₁ + 1 = 69 teeth.

The causative agent of the zero-pulse sensor is adopted in the form of a disk with one cavity Z ₀ = 1. Note. If necessary, grind the outer diameter of the gears Z ₁ and Z ₂ by two radii along the pitch circles of the gears.

 2. The angular pitch of the gears.

.

.

 3. The angular difference in the step of the pathogens (discrete angle).

.

.

4. The diagram of the angular arrangement of the impulses of the sensors D _MF , D _non (Fig. 4) (when M _cr = 0 by rotation of the shaft in one revolution)
Counting pulses and _MF and _non vernier And when M _cr = 0 are the same (and are aligned) the leading edges of the start and end of each turn.

.The duration of the pulses δ _y (angular) And _mid , And _non equal

.

5. The coincidence of the pulses And _cf , And _non at θ> 0 and M _cr > 0.

In the previous diagram, when M _cr = 0, zero pulses coincide. As the increment θ, the sequence of coincidence of pulses for each increment of θ by the angle Δ _y is performed sequentially on the first pair of pulses And _cf1 , And _non1 , on the second pair, etc.

Thus, the angle φ _c coincidence pulse of each pair of teeth proportional to the angle of twist of the shaft.

угловая разность шага шестерен Δ_у укладывается Z₁ раз.Into the pitch angle of the vernier gear

the angular difference of the pitch of the gears Δ _y fits Z ₁ time.

,
т.е. угол Δ_у= 0,0767^° кратно укладывается в шаг Ш_нон = 5,2174^o.

,
those. the angle Δ _y = 0.0767 ^° fits into the step W _non = 5.2174 ^o .

.Since the required measuring range of the twist of the shaft is θ = 2 ^{°, the} number of a pair of combined pulses N _psi (corresponding to the angle of twist of the shaft) is defined as

.

In this case, the leading edges of the pulses And _cf and I _non did not coincide, but these pulses with an angular duration δ _{y were} combined to form a pulse (and signal) of coincidence And _coincided (Fig. 5).

.Verification What weighs 0.0685 “teeth” in angular units?

.

The mismatch of the leading edges of the pulses And _c and And _non on X = 0,00526 ^o less than δ _y = 0,03835 ^° , which should be done with a digital (discrete) method of processing information.

6. The angle of coincidence φ _c , at which the summation of the count pulses stops.

.

.

.When the shaft is twisted by θ = 2 ^{°, the} angular transmission coefficient K _{ps of the} method will be

.

 7. The error of the method.

.The relative error related to the nominal value θ = 2 ^° will be

.

8. The formation of a constant value of the angular pulse duration And _MF , And _non when changing the speed of the shaft.

In FIG. 2 is a block diagram that provides for the use as a pulse generator of pulse-converted pulses And _ref sensor D _sc , the repetition rate of which tracks the shaft speed.

Therefore, the duration δ of _the pulses And _cf , And _non should be monitored by the revolutions of the shaft in the same dependence (proportion). For this purpose, the circuit provides formers of duration ФД ₁ , (ФД ₂ ) in the same circuit design.

Below is a diagram of pulses And _counting , And _sc , And _learning , δ _τ , And ₀ , on the sensor channel D _sc . Duration And _counting over time forms PD _1/2 /.

Angle δ duration _at a pulse is generated and _MF and the front edge of the pulse and ends _sch.nach the accumulation (predetermined) pulse and _uchshi arriving after frequency multiplier of step pulses of 32 pulses.

Step pulses And _students are formed after the signal frequency multiplier D _cf , the signal of which, due to the adopted number of gear teeth of the counting gear Z ₁ = 68, is close to the harmonic shape and allows performing the multiplication action.

.We take the coefficient of the pulse multiplier And _{with the} frequency multiplier of the step pulses equal to K = 2 ¹² = 4096, then (Fig. 6, diagram) the number of pulses ∑ U _{taking into account the} formed angular duration will be:

.

.In order to schematically solve the shaper ФД ₁ (ФД ₂ ), we take the number уч _U = = 2 ⁵ = 32. This simplification will introduce an additional error into the measurement. Given this additional (introduced) error, the measurement error will be

.

 9. The sum of the measuring pulses (the capacity of the counter of the useful signal of the ATP and the idle counter SHX).

The nominal angle of coincidence φ _c at θ = 2 ^° is 136 ^{o of} rotation of the shaft (p. 6) and corresponds to a coincidence on 26 pairs of teeth of the gears of the sensors D _sc , D _non .

To reduce the "weight" of the lost impulse AND _ism when the commands generated by the control system of the control system do not coincide, a frequency multiplier of the measuring pulses is applied. Based on this, at φ _c = 136 ^° (the 26th pair of teeth coincides), the UCHI coefficient is taken equal
K _meas = 2 ⁷ = 128.

.If the received value K _MOD shaft for rotation through an angle equal to W _MF = 5,2941 ^o 128 pulses formed and _edited, and the moment of coincidence pulses and _MF and _non And on the 26th pair of teeth (φ _c = 136 ^°) amount gears measuring pulses will be

.

.The price of the "lost" impulse And the _change in percent will be

.

полезного сигнала счетчика полезного сигнала СПС принимается с резервом

.10. Total counter capacity

useful signal counter useful signal SPS is taken with a reserve

.

холостого хода - СХХ принимается равной емкости СПС.11. Total counter capacity

idle - SHX is taken equal to the capacity of the ATP.

 12. The error.

The total measurement error at the accepted and given values of Z ₁ , Z ₂ , θ will be during arithmetic calculation by the method of summing the components and impulse loss And _ism due to the mismatch of the commands of the control system.

.

.

13. The angular duration δ _y (p. 8) of pulses And _cf , And _non is formed by 32 pulses And _after - a frequency multiplier of step pulses.

The time duration δ _{τ of the} initial pulses And _{counting is} taken equal to half the time required to complete the rotation of the shaft at an angle δ _y (Fig. 6).

.The period of rotation of the shaft at n _max = 9000 rpm

.

,
временная длительность δ_τ на этих оборотах вала будет

.The period of rotation of the shaft at n _min = 4000 rpm

,
time duration δ _τ at these shaft revolutions will be

.

.In order to simplify the scheme of FF ₁ (FF ₂ , FF ₃ ), the duration of the initial pulses And ₀ ; And _sch.nach ; And _{non.nach the} same

.

14. The equation of the method of the vernier digital meter M _cr .

.In paragraph 5 of the calculation, it is shown that in the pitch angle of the vernier gear Ш _non , the difference Δ _{between the} steps of the counting and vernier gears fits multiple times Z ₁ time (68 times)
Taking into account that the increment of the angle of rotation of the shaft θ by Δ _{y is} proportional to the sum of the number of measuring pulses ∑ U _ISM , is equivalent to the multiplication factor of the measuring pulses K _ISM (item 9), it follows that the sum of the measuring pulses from the beginning of the measurement to the number of teeth gears N _psi , on which the combination of impulses And _cf , And _non , providing the formation of a coincidence pulse And _coincide . expressed as:

.

.In the specific case of the calculation at Z ₁ = 68, Z ₂ = 69 and K _rev = 128

.

Using the characteristic of the elastic twist of the shaft from the applied torsion moment obtained under static calibration conditions (i.e., θ = f / M _cr (based on the number ∑ U _ism , the effective torque during operation of the product is determined).

The results of the calculation of the specific application of this method show:
1. The measurement error of the torque at the nominal mode of the product is provided no worse than 0.25% (According to the calculation of 0.1% p. 12).

 2. This method provides output information for the product control system in the form of a single code (Fig. 2).

 3. The method provides the ability to conduct end-to-end verification of the technical condition of the meter during operation of the product without the use of external control systems (Fig. 2).

 4. During debugging with a nonius digital digital torque meter, it is possible using the instrument method to correct technological inaccuracies and tolerances for the manufacture and assembly of meter assemblies that take these inaccuracies into account by dialing the position of external electrical keys (Fig. 2).

Claims (1)

 1. The method of measuring the angle of rotation of the shaft, twisted by the action of torque using the Nonius scale with a continuously rotating shaft, characterized in that the zero-pulse sensor, a control inductor with a slot, offset in advance in the angular direction of rotation of the shaft relative to the zero tooth gear counting sensor, and a pulse shaper forms rectangular zero pulses with a given duration of time, a counting sensor with frequency multipliers, respectively, measuring and step pulses The corresponding short-time rectangular measuring and step pulses are continuously formed, the counting sensor with a counting gear and the vernier sensor with a vernier gear with the corresponding pulse shapers, as well as the angular duration shapers, form rectangular counting pulses and nonius pulses, the duration of which is limited by the number of periods of the repetition rate of the step pulses , with the coincidence of the counting and vernier pulses along the angle of rotation of the shaft, pulses of coincidence are formed by the coincidence circuit eniya coincidence signals and the control circuit, the alarm coincidence stop filling rectangular measuring pulse counters idle and useful signal and reset pulses for the measuring light to the angular position of the shaft at which the zero pulse sensor and the control inductor of rectangular shape zero pulses.

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