SU756191A1 - Device for measuring deformation of bodies of revolution - Google Patents

Description

The invention relates to the field of measurement technology, namely, devices for measuring strain.

A device for measuring the deformations of products is known, which contains a light source, a diaphragm, a mechanical scanning device associated with the diaphragm and a light source, a photodetector and a recorder [11The disadvantage of this device is that it does not measure the deformations of rotating products, since this increases the error measurements.

The closest to the proposed technical solution is the device for measuring the deformations of bodies of revolution, comprising a cathode ray tube with screen with metallovolokonnym deflecting system ¹⁵ conductive, sawtooth current generator, whose output is connected to the deflection system, amplifier and recorder [2].

However, this device does not provide a measurement of _two radial runout rotating bodies, since movement of the bodies due to the beats, perpendicular screen cathode ray tube.

2

The purpose of the invention is the measurement of the radial beats of the bodies of revolution.

This goal is achieved by the fact that the device is equipped with a second electron beam tube with a metal fiber screen and with a deflecting system, a delay line connecting the sawtooth current generator to the deflecting system of the second tube, a rectangular pulse generator, with the first output of which is connected to the cathode of the first electron beam tube, the second delay line, connecting the cathode of the second tube to the second output of the rectangular pulse generator, calculator, switch, transducer of the amplitude of the pulses into the code, soy Inonii series with the first output of the amplifier, the pulse counter with the trigger sequentially connecting the computer and the second input of the amplifier and shaper connecting the second input of the pulse counter with the third output current of the sawtooth generator.

FIG. 1 shows a diagram of the device;

in fig. 2 - time diagrams of currents

sweep Gr and 1p, entering the deflecting system of the electron-beam tubes;

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in fig. 3 - timing diagrams of rectangular pulses with voltages and ' _p and υί! ; in fig. 4 - timing diagrams of the measured pulses with stresses and ₍ and and g; in Fig. 5 - the deformation scheme of the investigated body of rotation.

The device contains electron-tube 1 and 2, installed one against the other on both sides of the measured rotation body 3. CRT screens 1 and 2 are installed in parallel forming a rotation body 3 at a short distance, providing charge transfer from the CRT electrodes. 1 and 2 on the surface of the body of revolution. The sawtooth generator 4 is connected to the deflection system 5 of the CRT and through the delay line 6 is connected to the deflecting system 7 of the CRT 2. The output of the 8 rectangular pulse generator is connected to the cathode of the CRT 1 and through the second delay line 9 to the cathodes of the CRT 2. On the shaft of the body of rotation 3 installed current collector 10, which is grounded through a resistor 11 and connected to the amplifier 12. The output of the amplifier through the converter 13 amplitude pulses to the code and the switch 14 is connected to the input of the computer calculator 15. The second output of the amplifier 12 is connected to the pulse counter 17, connected nnym to the third input of the calculator 15 and through a shaper 18 - to the third output of the generator 4 sawtooth current.

The device works as follows.

The deflection system 5 of the CRT from the generator 4 sawtooth current is fed by a sweep current 1'p (Fig. 2a), and rectangular pulses with a voltage u ' _n (Fig. 3a) are sent to the cathode of the ELTZ 1 from generator 8. The electron beam of a CRT 1 scans the electrodes of a metal fiber screen, the width of which exceeds the length of the measured rotation body 3. When the beam hits the screen electrodes as a result of a potential difference between the latter and the object of rotation, a breakdown of the air gap occurs, which results in a transfer charge from the electrodes to the side surface of the body of rotation 3. Transferred charge in the form of a current flows along the circuit: body of rotation 3, current collector 10, resistor 11. On the latter, a form the impulse with voltage and ι and the duration tffig. 4 a) proportional to the distance between the screen electrode and the surface of the object of rotation 3. The voltage removed from the resistor 11 at each point, the distance between which is equal to the electrode placement step, will depend on the gap between the CRT electrode with MVE 1 and the surface of the body of revolution, i.e. will show the change in the radius of the body of rotation 3 and the position of its axis of rotation, that is, its beating. On the deflecting system of the CRT 2 from the sawtooth generator 4 through the first delay line 6, a sweep current 1p is emitted with a delay of x from the sweep current I p of the deflecting system 5 of the CRT 1 (Fig. 2b), and to the cathode of the CRT 2 from the generator 8 through The second delay line U receives rectangular pulses Όίί, also shifted by time ί (Fig. 3 b). The shift of the scanning current Gy and rectangular pulses ύπ is necessary so that the signals received from CRT 1 and 2 are separated in time from each other and make it possible to measure at the same level the generatrix of the body of revolution. Since time is negligible, practically the measurement is made along two diametrically located lines. The electron beam of a CRT 2, like the CRT 1, scans through the electrodes of a metal fiber screen. When the beam hits the screen electrodes as a result of the potential difference between the electrodes and the body of rotation, a breakdown of the air gap occurs, the screen of the CRT 1-forming object of time 3, which also results in charge transfer from the electrodes to the side surface of the body of rotation. The transferred charge flows along the circuit: measured body 3, current collector 10, resistor 11. The latter forms a pulse with voltage and g and duration τ, (fig. 4 b) proportional to the distance between the electrode and the surface of rotation 3. The beam of the CRT 2 scans along the length measured body 3, traces the generator of the latter with a delay of time g. The voltage taken from resistor 11, as in the case of a CRT with MVE 1, will show the change in the radius of the body of rotation 3 and the position of its axis of rotation.

The scanning speed of a beam on CRT screens with MVE 1 and 2 significantly exceeds the linear velocity of the body of rotation 3, so we can assume that the probing signal passes instantly, that is, the scan is along the generatrix of the body of rotation. From resistor 11, the pulses taken with amplitudes u and _i (Fig. 4c) are amplified in amplifier 12. From the first output of the last amplified pulses enter amplitude converter 13 into the code and through switch 14 enter the input of computer 15. From the second output of amplifier 12, producing an amplitude limiting and, and, and signals _g (Fig. 4 g), through the trigger 16 pulses are fed to one of the inputs of the pulse counter 17, indicating the number of measured points. From the third output of the sawtooth generator, the incoming signal is converted into the current collector 10, and is fed to the second input of the pulse counter 17, controlling the setting to the zero state of the latter. The calculator 15 determines the deformation and the beats of the rotating body 3 according to the following formulas:

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6

five

a ₌ _ε ^ ο & οο_τ and ___ ι,

t "'υ _β ίΰφ'

* - - &> · ^{δ £ = δ} " ^tl, "'

where l is the radial deformation of the body of revolution;

x is the displacement of the body of rotation with beats;

Δ £ is the axial deformation of the body of revolution; Δη is the difference of the number of pulses that passed to the input of the counter 18 in the dynamic and static modes;

T - the period of the pulses of the generator 8;

Od - the speed of scanning the beam along the generatrix of the body of rotation;

6 ₀ - absolute dielectric constant;

δ is the dielectric constant of air;

5 - the area of the charging spot formed on the surface of rotation; θο is the potential between CRT with MVE and

rotation body;

g is the resistance value of the resistor 11;

Έ —time of discharge development; and o is the amplitude of the pulses when the body is stationary 3;

and ₍ - the amplitude of the pulses arising from the discharge from the screen of a CRT 1 during the rotation of the body 3;

and _{2 — the} amplitude of the pulses that occur when discharging from a CRT screen 2

when the body rotates 3.

The device allows to obtain divided information about the deformations and beats of the bodies of revolution.

Claims (1)

Claim A device for measuring deformations of rotation bodies, containing a cathode-ray tube with a metal fiber screen and with a deflecting system, a sawtooth current generator whose output is connected to a deflecting system, an amplifier and a recorder, characterized in that it also provides for measuring radial beats of rotation bodies the second electron-beam tube with a metal-fiber screen and with a deflecting system, a delay line connecting the sawtooth current generator with the deflecting system of the second tube, a generator straight coal pulses, with the first output of which is connected to the cathode of the first cathode-ray tube, a second delay line connecting the cathode of the second tube to the second output of the rectangular pulse generator, calculator, switch, pulse amplitude-to-code converter connected in series with the first output of the amplifier, pulse counter with trigger, sequentially connecting the calculator and the second output of the amplifier, and the driver connecting the second input of the pulse counter with the third output of the sawtooth generator current.