Abstract
Purpose is substantiating ways to enhance durability and bearing capacity of open gears of ore-pulverizing drum mills as well as efficiency of engineering solutions concerning the increase in their unit power at the expense of drive improvement. Methods. Results of continual experiments and theoretical studies have been generalized as for the abrasion of working surfaces of open gear teeth of drum mills and factors influencing load distribution in terms of a tooth rim width. Findings. Comparative analysis between domestic mills and the best world-class products has been carried out. Ways of solving problems to design large-capacity mills with a gearbox drive have been demonstrated. Influence of hardness of working teeth surfaces on their durability has been evaluated quantitatively. The factors, governing load distribution in terms of tooth rim width, have been analyzed. Use of self-adjusting gear drives for open gears has been evaluated. Originality. Functional relation between stress-strain properties of working surface of teeth; the number of running-in modes, determined by operational conditions; and durability of open gear has been identified. The factors, influencing load distribution in terms of tooth rim width, have been considered. Practical implications. It has been shown that use of such open gears, where hardness of working surface of gear teeth is (500-600) H1B1 and that of a tooth rim one is (260-300) H2B2, makes it possible to provide almost wear-free operation. Moreover, it is the required condition for the performance of a tooth rim with two drive gears.
Highlights
MethodsResults of continual experiments and theoretical studies have been generalized as for the abrasion of working surfaces of open gear teeth of drum mills and factors influencing load distribution in terms of a tooth rim width
It has been shown that use of such open gears, where hardness of working surface of gear teeth is (500-600) H1B1 and that of a tooth rim one is (260-300) H2B2, makes it possible to provide almost wear-free operation
Open gears, having relatively low hardness of working surfaces, i.e. (260-300) H1B1 and (180-200) H2B2, are subject to abrasion advancing in proportion to wear of the open gear
Summary
The methods to calculate open gears as for their wear durability rely upon the experiments carried out using representative line of self-adjusting ball ore-grinding mills, and ore-pebble ones in terms of Inhuletskyi MPP, Novokryvorizkyi MPP, Lebedynskyi MPP as well as in terms of crashing mills of Prydniprovska TPP. Analysis of the experimental data has helped determine that an open gear wear process has three distinctive periods: running-in period, stable period, and catastrophic one The latter results from 3.5-4.0 mm wear of tooth working surface. Relying upon the experimental data and Expression (2), both analysis and evaluation of the average velocity of working teeth surface wear in terms of a stable operation will be performed using the formula: U1(2)0 = 60 1(2)Kn1(2)v2L1(2) , mm/h,. K – a design parameter involving geometrical and kinematic parameters of gear pair [37]; n1(2) – is rotation of gear wheel; v2 – the number of gears operating with a tooth rim; L1(2) – a coefficients involving dissimilarity of abrasion influence of environment, physicomechanical properties of material, and teeth loading conditions for the controlling case from those ones in terms of which Ф1(2) parameter was identified.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
