SU112371A1 - Torsiography method - Google Patents

Description

The subject of the invention is a method for studying torsional vibrations (torsiography), based on measuring the thermal electromotive force in the friction zone of two contacting surfaces.

The peculiarity of the proposed method is that the annular track is ground on the shaft to be examined or a smooth metal ring is put on the shaft in contact with the tip of the metal rod pressed against the outer surface of the ring, which together with the metal forms the most thermally electromotive force in the friction zone. Based on the indications of a magnetoelectric oscilloscope, the electrical circuit of the vibrator of which includes conductors from both rubbing parts, and the experimental graph "thermal electromotive force - speed of relative displacement of rubbing parts are determined by calculation using the formulas for the sought amplitude of torsional vibrations.

The drawing shows a diagram illustrating the proposed method of torsiography.

The technique of the method is that an annular track is ground on the test shaft or a smooth metal ring is put on the shaft. On the smooth surface of the ring track or metal ring, the metal bar 2 is pressed against the part 2. The material of the rubbed bunker is selected based on the conditions for achieving the maximum thermoelectromotive force (nanometer, constantan iron).

A shaft-rod is connected to an oscilloscope, while one of the wires of the vibrator 3 is brought to the rod, the other through a sliding contact to a rotating shaft. The oscilloscope records the change in the velocity of the relative movement of the shaft and the rod during torsional vibrations.

The frequency of torsional vibrations is determined directly from the waveform taking into account the scale of the time coordinate. Amplitude

№ 112371

torsional vibrations are as follows. The change in thermoelectromotive force expresses the change in speed relative to the movement of the rubbing pair; therefore, the oscillation curve can be expressed by the equation:

(t) where:

/ - time, V - speed.

The time traveled - the path (where / is the oscillation frequency) is the amplitude of oscillation a and can be expressed by the equation:

If the equation v (S} (t) is graphically represented by sinusoids, then the amplitude value can be expressed by the equation:

U.Kote - U a

The magnitudes of the maximum velocity (v, aKc) and average velocity (y) are determined from the experimentally obtained plot of the thermoelectromotive force — the speed of the relative movement of the rubbing parts.

Subject invention

The method of torsiography, characterized in that, in order to study torsional vibrations according to the measurement of thermal electromotive force in the area of the two contacting parts, a circular track is polished on the shaft under test or a shaft is put on the shaft in contact with the tip of the rod metal, providing, together with the ring metal, the formation of the greatest thermal electromotive force in the friction zone, and, according to the readings of the magnetoelectric oscillator The scanner, in the electric circuit of the vibrator of which the conductors from both sliding parts are included, and the experimental graph "thermal electromotive force - the speed of relative movement of the sliding parts are determined by calculation using the formulas for the sought amplitude of torsional vibrations.

(t) dt.

2g.-f