CS199473B1 - Shock absorber of rotary vibration exciter with slide along matter - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a shock absorber of a rotary vibration exciter with a mass of material.

In the prior art mass transfer vibration exciters, the so-called blasting exciters, the moment of eccentric masses changes to a lower value when a certain rotational frequency is reached. This change in the moment of the eccentric masses is caused by the spontaneous adjustment of the exciter mass by the centrifugal force. The exciters are suitable if the torque change range of the eccentric masses is relatively small and the sliding mass is relatively large. They are used mainly for treads of vibratory rollers, which are driven only in oscillating motion and are not equipped with traction drive. The drum treads, in which the vibration exciter also has a hydrostatic drive and brake, require that the vibration exciter and hence the sliding masses are small. If the range of change in eccentric mass moment is to be maintained or increased, the displacement of the transfer mass must be increased. However, this will increase the velocity of the transfer mass at the moment of impact on the rotor and create adverse shocks to the load-bearing parts of the machine, and in particular expensive roller bearings in which the rotor is mounted.

These drawbacks are overcome by the shock absorber according to the invention, which consists of two stops which are fixed in plates of the transfer mass and two inserts with spring elements fixed in a constant eccentric mass. The individual stops are located opposite the inserts with damping elements, the damping elements being ring springs, pneumatic or hydraulic dampers.

In the arrangement, the shock absorbers of the invention absorb 70% of the impact energy by friction of the annular springs; this reduces the stress on the machine's supporting parts, especially the bearings. The annular springs do not lose the ability to return the transfer masses to the desired position.

In the accompanying drawing, one embodiment of a shock absorber according to the invention is shown schematically in longitudinal section of an exciter with a displacement mass passing through the exciter axis and the guide bar.

The vibration exciter with a transfer mass and a shock absorber consists of a constant eccentric mass 1 supported in bearings 2, 2 'and a transfer mass consisting of plates X, fa', four connecting rods 12 and stops fa, fa. The transfer mass plates X, f and f are still connected by two guide rods A and the entire transfer mass is slidably mounted in a constant eccentric mass χ by means of the guide bushes f through which the guide rods 8 pass. Between the plate fa 'and the constant eccentric mass X, springs fa are mounted on the connecting rods 12. The plates X, fa 'are provided with stops f a, f a, which in the extreme positions abut the inserts 10 mounted in a constant eccentric mass X. An annular spring 11 is inserted between the inserts fa, 10 in the biased state.

The constant eccentric mass χ rotates in the bearings 2, 2 'and the displacement mass is held in the initial position χ by the springs fa. If a certain number of revolutions of the entire system, i.e. the constant eccentric mass X and the displaceable masses, are exceeded, the centrifugal force of the displaceable mass of the spring bias fits, and the displaceable mass is moved from the starting position X to position II. Damping of the displacement mass to the constant eccentric mass X when moved to position II is attenuated by a stop fa which, before reaching position II, strikes the insert fa, which compresses the annular spring χχ. Compressing the annular spring 11 converts the impact energy into deformation work and heat. Displaceable material then assumes the position II _S in which is supported by the eccentric mass constant χ. When the system speed decreases, the centrifugal force of the transfer mass decreases, which is then overcome by the force of the compressed springs fa. As a result of this force, the transfer mass is moved back from position II to the starting position χ. The recoil of the transfer mass to the constant eccentric mass 1 is damped by means of a stop 6. Before reaching the starting position X, the stop 6 hits the insert 10 which compresses the annular spring XX. After the impact energy has been converted into deformation work and heat, the annular spring 11 returns the transfer mass to the initial position χ.

The shock absorber according to the invention can be used in tandem vibratory rollers and in contact vibrators provided with a vibration exciter with a displacement mass.

Claims (2)

A shock absorber of a rotary vibration exciter with a displacement mass, characterized in that it is formed by stops (7,8) mounted in the displacement mass plates (3, 3 ') and inserts (9,10) mounted in a constant eccentric mass (10). 1), in which the damping element (11) is located, the stops (7,8) being positioned against the inserts (9, 10). Shock absorber according to claim 1, characterized in that the damping element (11) is a biased spring, a hydraulic damper or a pneumatic damper.