Research On Influence Of Friction Between Hammers And Hammer Pivots On Vibration Of Hammer Mill's Rotor

Because of high productivity, low price and good applicability, hammer mill is widely used in many industries, such as grain and foodstuff processing industries, pharmacy industry etc. However, as a difficult problem, vibration and noise haunt the factories which use hammer mills all the time. Violent vibration makes more mechanical failures, shortens nature life of equipment, increases largely the energy waste during running, and brings drastic deterioration to the working circumstance.Vibration of rotor system without active parts has been researched intensively in engineering sector. But, hammers, the main part of the hammer mill's rotor, are rotatable relative to the rotor. The traditional method which paying no attention on active parts on rotor makes it's impossible to uncover entirely the vibration mechanism of hammer mill.The vibration mechanism of hammer mill's rotor during rotating with high speed has been investigated from the point of view of the characteristics of symmetrical crank-pendulum groups and friction between hammers and hammers pivots. The dissertation can be divided into two parts, that is, theory analysis and experimentation testifing. Through both of them, the dissertation intends to uncover the unusual regulation behind the phenomenon of vibration of hammer mill. The conclusion of the dissertation could serve as reference to designing, manufacture and application of hammer mill, in expectation to decreasing energy waste, improving efficiency, and ameliorating working circumstance.In the part of theory analysis, the followings are studied.The discrete model of rotor structure is established on the basis of the elementary discrete unit of crank-pendulum mechanism.Based on the analysis of forces and motion of single hammer, the influence of friction between hammer and hammer pivot on status of hammer in running is testified. The concept of steady angle of deflection is brought forward. The formula of steady critical angle of deflection is introduced.Through the investigation of the departure of centroid of rotor's hammers group, the conclusion that the vibration magnitudes in steady rotating period at different start-up will...