SLOW OSCILLATIONS IN DRIVES OF MACHINE ASSEMBLIES

Machine assembly with additional degrees of freedom is considered. The method of direct separation of motions was used for research. It was shown that the braking vibration moment occurring by the reason of resonance effects in the driven object can lead to excitation of rotor oscillations of the assembly with a occurrence of slow oscillations of the vibration exciter rotor is demonstrated. frequency lower than the rotation frequency. Slow rotor oscillations represent a transient process to the stationary motion mode, which is established when an additional load torque occurs. Moreover, the maximum oscillation amplitudes will be relatively large. By the example of a vibration machine with an inertial drive, the occurrence of slow oscillations of the vibration exciter rotor is demonstrated.

BIDIRECTIONAL CONTROLLED MULTIPLE SYNCHRONIZATION OF UNBALANCED ROTORS AND ITS EXPERIMENTAL EVALUATION

In the paper the problem of multiple controlled synchronization of a pair of unbalanced rotors is considered. A new bidirectional control law is proposed for multiple synchronization of rotors. A linear analysis of the dynamics of a simplified system model is presented, demonstrating the control system robustness with respect to the parameters of the vibration machine and controller. The main part of the paper is devoted to the description of the experimental results obtained at the Multiresonance Mechatronic Laboratory Setup, demonstrating the efficiency of the proposed approach and revealing its application scope.

Determiantion of energy characteristics of material destruction in the crushing chamber of the vibration crusher

The crushing equipment is characterized by a significant energy-consuming system during the crushing workflow. The current trend in the development of such processes puts forward requirements for the development of new or improvement of existing energy-saving equipment. The essence of the solution to the problem in this work is determined by using resonant modes, which are inherently the most effective. The practical implementation of the resonance mode has been achieved taking into account the conditions for the interaction of the resonant vibration crusher with the material at the stages of its destruction. The degree of the stress-strain state of the material is taken into account, which was a prerequisite for identifying the potential for the development of a vibration load. Composed equations of motion based on a substantiated discrete-continuous model of a vibration crusher and processing material. An approach is applied to determine the stepwise destruction of the material with the determination of the required degree of energy. This methodological approach made it possible to reveal the nature of the process of material destruction, where energy costs at the stages of crack formation, their development and final destruction are taken into account. It was revealed that the greatest energy consumption during the operation of crushers goes into the kinetic energy of the crushing plates and the potential energy of deformation of the springs. The proposed model is common for any design of a vibration machine and its operating modes. The stable resonance mode has made it possible to significantly reduce the energy consumption for the course of the technological process of material grinding. The results obtained are used to improve the calculation methods for vibratory jaw and cone crushers that implement the corresponding energy-saving stable zones of the working process.

Wood pellets transport with vibrating conveyor: experimental for DEM simulations analysis

This work presents a comprehensive overview of the mechanical-physical parameters of the transport material affecting the vibratory transport. For this purpose, spruce pellets of different lengths, oak rods and spruce crush were tested. The determined parameters were particle size distribution and shape, internal friction, static and dynamic angle of repose. The samples were transported by a patented validation vibrating conveyor. Various settings were used. The results show that by changing the shape, it is possible to reduce friction or resistance as well as energy intensity during transport. It was observed that perfect shapes and lighter particles have lower friction, but a more pronounced bounce. Therefore, it does not form a typical pattern during transport, as in the case of an imperfectly shaped one. There is also included a simulation of the discrete element method. The study shows the possibility of the vibration machine where the material can be conveyed either directionally or sorted.

THE SYSTEM OF FORMING THE CONTROL MODE OF THE ELECTRIC DRIVE DURING THE START-UP OF THE VIBRATION MACHINE

The above resonance vibration machines are widely used in various industries, but have a number of shortcomings associated with increasing of the oscillations amplitude when passing the resonance zone during start-up. It is noted that to reduce the oscillations amplitude and quickly pass the resonance zone, it is advisable to use a frequency-controlled electric drive with the formation of additional control effects. Features of frequency start of the electric drive of the vibration machines are noted. The structure of the electric drive control system during passing the resonance zone in the process of starting the above resonance vibration machine in the form of a block-scheme is proposed. The algorithm of operation of the control system is given.

Low frequency vibratory cleaning of paint and rust contaminants from machines parts

This work investigates the effect of low frequency vibratory processing for cleaning and washing various machine components parts from rusts and old paints deposits. The experimental investigation was carried out with special prepared samples that were weighted and exposed to paints and rust contaminants. These samples were treated in universal horizontal vibration machine UVHM 4 × 10 with different combination of instrumental processing medium, process fluid, machine amplitude and frequency of oscillations. They were periodically reweighted after processing and compared to etalon with control of quantity of dust that have been removed, sample cleanliness and also other functional parameters. Statistical analysis has been used to characterize ongoing process and full factorial analysis to establish experimental parameters dependency. The result is showing the complex dependence of samples cleanliness to each processing parameters like processing time, amplitude of oscillations, frequency of oscillations, process fluid parameters, instrumental medium, etc. Between this parameters although the most important successively the amplitude of oscillations, the frequency of oscillations the processing medium and the processing fluid depending to his considered composition, the optimal processing time can be reach only by complex combination of all this parameters every of them carry an amplify coefficient. Low frequency oscillations can be used to monitor and optimize washing and cleaning operations of paints and rusts contaminations. That guarantees process automation, its effectiveness for a large industrial application.

Modelling of Equivalent Mass and Rigidity of Continual Segment of the Inter-Resonance Vibration Machine

The article deals with a continual segment of an inter-resonance vibration machine. In the form of a solid with distributed parameters this segment combines two defining parameters, namely: the inertial parameter of reactive: masses and appropriate rigidity of elastic coupling. These operation factors are revealed only in dynamic processes and are clearly not included in the parameters of the continual segment. Analytical dependences are developed for modeling of defining parameters of an inter-resonance system, namely: reactive mass and appropriate rigidity of elastic: coupling. Parameters of the reference point of the continual segment passing through its center of velocity are studied. The inertial parameter of the reactive mass and the rigidity of elastic coupling were modeled by the Rayleigh-Ritz method. The reliability of the results of theoretical research was confirmed experimentally and the parameters of the partial frequency of the continual segment were determined.

RESEARCH OF THE IMPACT ON PRODUCTIVITY OF PARAMETERS AND OPERATING MODES OF THE VIBRATION MACHINE DRIVE FOR CLEANING AND WASHING CONTAMINATIONS BY SUBMERGTD STREAM JET WITH SOLID PARTICLES

Analyzed the methods of cleaning and washing, the design of machines with a vibration drive. The choice of a specific method of cleaning and washing is determined depending on the type and properties of contaminants, on the requirements for the cleanliness of products, and the type of production. The scheme of operation of a vibrating machine for cleaning and washing machine parts in a pulsating flow of liquid with solid particles is considered and parameters that affect its performance are determined. The results of studies of physical phenomena during the formation of a pulsating submerged jet are presented, and the influence of design parameters and modes of the drive robots on the maximum jet pressure is determined. An analytical dependence of the maximum instantaneous pressure of the jet has been obtained experimentally, which makes it possible to determine the optimal ratios of parameters when designing a vibration machine for cleaning and washing contaminants.