SU1733224A1 - Electromagnetic resonance pulse machine - Google Patents

Abstract

This invention relates to pulsed machines. It is intended to excite resonant oscillations in objects of influence, for example, to destroy oversized blocks of rock. The purpose of the invention is to increase the efficiency of the machine by reducing energy consumption, material intensity and noise level. The goal is achieved by excitation in a working tool of 2 natural oscillations that are tuned to resonance with the natural vibrations of the destroyed block 6. To do this, first in a working tool made of an elasto-elastic electrostrictive material,

Description

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l through the electrodes 5 excite forced mechanical oscillations that adjust the frequency to resonance with the natural frequency of the block 6 to be destroyed. Then, by means of a constant electric field supplied by the electrodes 4, the natural frequency of the instrument 2 and the forced frequency of the electric field oscillate electrodes 5.

The invention relates to mechanical engineering, namely, pulsed devices, and is intended to excite resonant oscillations in objects of limited size, for example, in oversized pieces of rock, with the aim of destroying them, the foundations of buildings being demolished and separate separate structures, can also be used to excite them. resonance oscillations in the walls of bunkers, bodies of dump trucks and railway cars in order to clean them from adhering and frozen foreign materials.

A known electromagnetic percussion machine designed to destroy materials, which includes a housing, a working tool, an actuator comprising a power stroke coil with a magnetic conductor, a firing pin, and a striker return device.

The electromagnetic percussion machine has a drawback that is common to all known electromagnetic pulsed devices that use a drive with working and idling coils, and for the destruction of materials - pits: vortex currents occur in the striker, working tool and other ferromagnetic elements, resulting in energy losses; the device is cumbersome and material-intensive, and the movements of the working tool and striker are accompanied by noise.

The purpose of the invention is to increase the efficiency of the machine by reducing energy consumption, material consumption and noise level.

FIG. 1 shows a diagram of a resonant electric machine of a pulsed action; figure 2 - section aa in figure 1.

The machine includes a housing 1, a working tool 2, made of an elastic-elastic, electrostrictive material capable of deforming under the action of an external electric field, a clamping device 3 connected to the housing to hold the working tool 2 cylinders. To change the rigidity of the working tool by smoothly changing the potential difference across the electrodes. 4. The onset of resonance is judged by an increase in the amplitude of oscillations. After a complete resonant tuning, the working tool is applied to the free surface of block 6 and held in this state until the block is completely destroyed. 2 Il.

shape in a given position under different disturbances, a drive comprising two pairs of electrode plates 4 and 5, made in the form of conductive elastic-elastic strip coatings located along the working tool and connected respectively to controlled sources of constant and alternating voltage (not shown).

A resonant electric pulse machine operates as follows.

First, prepare the machine for operation. Manually or using known devices (hand truck, self-propelled chassis, car lift, etc.), the machine is brought in and applied by the free (loose) end of the working tool 2 to the object of influence, for example, on the surface of an oversized piece of rock 6. By switching on a source of alternating electrical voltage, an alternating electric field is applied through the electrodes-plates 5 to the working tool 2, as a result of which forced mechanical vibrations are excited in the electrostriction material of the tool 2. Since the source of alternating electrical voltage is adapted to control the frequency of oscillations of this voltage, then, by changing the frequency of oscillations of the applied electrical

the field and the forced frequency of mechanical oscillations of the working tool caused by it reach resonance of the forced frequency of mechanical oscillations of the working tool 2 and the natural frequency of oscillations of the oversized piece 6 of the rock. The resonance is determined visually by the maximum value of the amplitude of oscillations of the surface of the piece 6. Preparation for the operation of the machine is completed by resonant adjustment, i.e.

natural frequency of oscillation of the working tool and forced frequency

fluctuations of the applied alternating electric field, for which the stiffness of the elastic-elastic electrostriction material of the working tool 2 is changed by applying to the material a constant electric field through the electrodes-plates 4 connected to a constant electric voltage source. At the same time, the free end of the working tool, oscillating under the action of an alternating electric field supplied through the electrodes 5, is detached from

the surface of the piece 2. A smooth change in the potential difference on the electrodes 4 entails a smooth change in the rigidity of the working tool 2 and the natural frequency of its oscillations. This resembles a change in the natural frequency of a string due to a change in its tension. As in the first stage of machine preparation for operation, the onset of resonance is judged visually by the maximum value of the amplitude of oscillations of the free end of the working tool, in which an integer number of hundred waves is excited. Only odd harmonics of natural oscillations with a node in the place of fixing the tool in the clamping device and an antinode with a maximum amplitude of oscillations at its free end are suitable for operation.

After the preparation of the machine for work is completed, the working tool 2 is pressed again with its free end to the surface of the oversized piece of rock 6 and is now held in the pressed state until the piece is completely destroyed. The destruction of the rock occurs from the inside due to the resonant absorption of the energy of the wave field and its concentration on the cracks inside the piece. In solid (monolithic) pieces, resonant oscillations are characterized by a rapid increase in the amplitude of the oscillations of the piece and its destruction due to extreme stresses in the material to be destroyed. The reduction of energy consumption in a resonant electric machine of a pulsed action is achieved by reducing the hysteresis 0

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losses due to internal friction E of the working tool material, since it oscillates at its own frequency, v improves the conditions for the transfer of the input energy to the rock block to be destroyed. The reduction in the material consumption of the machine is ensured by the compactness of the drive, since the functions of the working tool and the drive are combined in one element. The noise is reduced due to the unaccented interaction of the free end of the working tool with the interaction object, since the surface of the tool end is in contact with the surface of the rock block to be destroyed all the time, and the contact points move at the same speed (relative motion is absent). In addition to all this, in the process of operation, the machines excite the odd harmonics of the natural oscillations of the working tool with a stationary unit on the clamping device and an antinode (maximum amplitude of oscillations) at the free end of the tool. This provides vibration protection of the machine body from vibrations excited in the working tool, since, as is known, no vibrations are transmitted to the body through the nodal points.

Claims (1)

An inventive resonant electric machine of pulsed action, comprising a housing, a working tool, a drive, an adjustable source of alternating voltage, characterized in that, in order to increase efficiency by reducing energy consumption, material intensity and noise level, the working tool is made of an elastically elastic electrostrictive material, - the drive is made in the form of two pairs of electrode plates located along the working tool, equipped with a controlled source of constant voltage and connected to pusom clamping device, one pair of electrodes connected with an adjustable source of alternating voltage, other - with an adjustable source of DC voltage, and the working tool is secured in the clamping device. 2