SU1477870A1 - Arrangement for damping oscillations of fixed structure - Google Patents

Abstract

The invention relates to the protection of building structures from vibration and oscillations of technological equipment. The aim of the invention is to increase the efficiency of damping vibrations by providing an automatic adjustment of the device. This is ensured by the fact that the shaft 7 of the oscillation source is connected to the shaft 9 of the centrifugal tachometer sensor 10. The latter is connected by means of the lever 12 and the cables 13 to the movable supports 4 on which the beam 5 with the inertial mass 6 is fixed. supports 4 and, consequently, the change in stiffness of the beam 5, which provides an automatic setting of the damper. 1 h. P. f - ly, 4 Il.

Description

The invention relates to the construction, in particular to the protection of building structures and structures from vibration and vibrations.

The purpose of the invention is to increase the efficiency of quenching kolabeniy by providing automatic adjustment of the device.

Figure 1 shows the device, a general view; figure 2 - node I in figure 1; on fig.Z - section aa in figure 2; figure 4 - section bb in figure 2.

The harmonic oscillation source 1 is mounted on a vibration-proof structure 2. On the support platforms 3 there are movable supports 4 of a dynamic damper, including an elastic beam 5 with a concentrated mass 6. Shaft 7 of the excitation source is connected to the drive shaft of the variator 8, which is connected longitudinally and movably with the shaft 9 of the centrifugal tachometer sensor 10, the rotating coupling 11 of which is pivotally connected to the movable supports 4 by means of a two-arm lever 12 and non-expandable cables 13, thrown over the blocks 14. Movable support 4 elastic connections 15 are connected to support sites 3.

The spring stiffness of a centrifugal tachometer sensor is nonlinearly dependent on the angular velocity of the excitation source

,one

G -

where tp

(About Pyhg

BUT

- the mass of the load at the end of the lever of the centrifugal sensor; angular velocity of the shaft of a centrifugal tachometer sensor;

A is the coefficient depending on the ratio of the sizes of the links of the centrifugal sensor. On the other hand, the frequency of oscillations of the load of the damper oscillations non-linearly depends on the estimated length of the damper beam

EI - beam stiffness;

M - the reduced mass of the quencher

fluctuations;

1 is the calculated length of the quencher beam, which varies with the movements of the supports 4.

five

0

five

0

five

0

five

0

five

To ensure reliable damping of oscillations of the damped structure throughout the entire range of frequencies of the exciter of vibrations, it is necessary to ensure synchronism of frequencies of the exciter and damper, which is achieved at constant masses m and M by selecting a nonlinear spring with a rigid characteristic and the magnitude of the change of the length of the damper beam.

The end of the lever 12 is connected to the centrifugal sensor 10 with the possibility of its rotation and simultaneous reciprocating movement of the end of the lever 12. For this purpose, the end of the lever 12 is made in the form of a fork with a slot 16, the height of which is equal to the diameter of the axes 17 located diametrically to the sleeve 18. The slot length 16 is shifted asymmetrically to the end of the fork of the lever 12 so that when the lower (movable) links of the centrifugal sensor 10 move up and down at the point of contact of the fork with the axles of the sleeve 18, no jamming occurs. The second end of the slotted forks without play is adjacent to the axis of the sleeve 18 when the centrifugal sensor is in the neutral position. The sleeve 18 itself, which surrounds the coupling 19 between its protrusions 20 and is provided with axes 17, is made of two half-rings connected by bolts in the plane perpendicular to the axis 17. The sleeve 21 and the coupling-shaft of the centrifugal sensor are placed with a low coefficient of friction, for example, from fluoroplastic. The lower, as well as the upper, end of the shaft of the centrifugal regulator has a bearing support 22 and is connected to the end of the lever 12.

The device for damping vibrations operates as follows.

In the operating mode of the harmonic oscillation source 1, the rotation of the shaft 7 is transmitted through the axis of the variator 8, which is longitudinally and movably connected to the shaft 9, to the centrifugal tachometer sensor 10. At the same time, the shaft of the centrifugal sensor 9 is fixed by the support 17 from vertical movements.

The movement of the centrifugal tachometer sensor 10, caused by a change in the frequency of the excitation, is supplied to the movable supports 4 through the coupling 11, the lever 12 and the thrusts 13, thrown through the blocks 14. In the steady state operation, the position of the movable supports 4 is constant and determined by the magnitude of the excitation frequency. Its increase is accompanied by upward movement of the coupling 11, the end of the lever 12 connected to it, the mutual convergence of the movable supports 4, which increases the rigidity of the damper beam 5 and, consequently, the frequency of its oscillations. With a decrease in the frequency of excitation, an increase in the length of the beam 5 of the damper occurs (a decrease in the frequency of its oscillations) due to lowering the lever 12 together with the clutch 11 and the choice of loosening the tension of inextensible cables by the return springs 15.

Taking into account that the spring stiffness of a centrifugal tachometer sensor nonlinearly depends on the angular excitation rate of the oscillation, and the oscillation frequency of the damper also nonlinearly depends on the change in the length of the damper beam, the synchronism of the oscillation frequency of the damper and the exciter is achieved by selecting a non-linear spring with a hard characteristic of the centrifugal tachometer sensor, lever, characteristics of the elastic beam and the mass of the damper,

In this case, a damper will be exerted on the damper side by a force equal to the disturbing and out of phase in any operating mode of the excitation source, since the stiffness (oscillation frequency) of the damper changes in the following mode due to a change in the excitation frequency.

Adjusting the stiffness (oscillation frequency) of the damper allows the

in comparison with the known solution, in the automatic mode there is an optimal tuning of the damper to the frequency of the source of harmonic oscillations in a wide range of its variation, which expands the scope of dampers. Tracking the natural frequency of the quencher for the excitation frequency, due to the proper selection of the device parameters, provides complete damping of the oscillations of the damped structure.

Claims (2)

1. A device for damping vibrations of a building structure from the vibration of technological equipment, including a beam with inertial mass and movable supports of the beam, mounted on supporting platforms, characterized in that, in order to increase the efficiency of damping vibrations by providing automatic adjustment of the device, it is equipped with a centrifugal tachometer - a cage sensor mounted on the shaft connected to the technological equipment shaft by one end and made with a movable coupling on the other, blocks attached to the supporting platforms, elastic elements connecting the movable supports with the supporting platforms, two levers with arms and cables, the latter being attached to the movable supports and one shoulder two shoulders of the lever, the other shoulder of which is made with a hinge attached to it by a sleeve, put on the shaft coupling. 2. The device according to p. Is distinguished by the fact that the tachometer sensor is made with a nonlinear spring with a rigid characteristic. Aa Fi, g.Z. 12 18 FSh.1