OPTIMIZING THE TECHNOLOGY OF RECONDITIONING LARGE HIGH PRECISION GEAR RIMS

Abstract

The subject matter of the research is issues related to the optimization of the technology for reconditioning large-size high precision gear rims of the drives of mining complexes, mine lifting equipment, heavy vehicles; these issues are a perspective trend for reducing the cost of reconditioning and operation of expensive unique equipment. The goal is to ensure intensifying production processes, increasing workloads and speeds, reducing the deterioration of high precision gear rims. The objective is to develop a new technology to optimize reconditioning large high precision gear rims. To achieve this, the following method is suggested – to machine gear rims after they have been surfaced by pre-milling with special hob cutters with a prominence and by final machining the teeth with special cutters equipped with hardmetal inserts that process teeth along the line of engagement, which does not require making full-length cutting teeth and increases the quality of machining, the durability of hardmetal milling cutters. The process of reconditioning of large high precision gear rims is a resource-saving technology, as compared with manufacturing new parts, this technology considerably reduces the cost of materials for manufacturing, decreases a number of process steps, reduces the cost of machining equipment, tools, cutting and measuring instruments. The smooth operation of a gear train can be ensured only at a constant gear ratio but due to manufacturing and operational errors, the gear ratio is not constant at every time, which intensify the deterioration of large high precision gear rims. The following results are obtained. The possibility and practicability of using hob cutters with a prominence (m = 20-28 mm) while rough cutting the worn and reconditioned large gear rims was proved. To obtain the necessary durability of rough milling cutters, it is recommended that the prominence angle be set within 8-10°. The use of hardmetal hob cutters for finishing makes it possible to increase the performance rate by 2 to 3 times as compared to high-speed cutters of other designs and to obtain the necessary quality and precision of manufacturing worn and reconditioned large gear rims. Conclusions. The technology for the optimization of reconditioning large high precision gear rims with the use of special and universal hardmetal single- and double-flute cutters that have both re-sharpened cutting elements and disposable rotary tools was developed and introduced.