Potentials of Vitrified and Elastic Bonded Fine Grinding Worms in Continuous Generating Gear Grinding

Maximilian Schrank,Jens Brimmers,Thomas Bergs

doi:10.3390/jmmp5010004

Abstract

Continuous generating gear grinding with vitrified grinding worms is an established process for the hard finishing of gears for high-performance transmissions. Due to the increasing requirements for gears in terms of power density, the required surface roughness is continuously decreasing. In order to meet the required tooth flank roughness, common manufacturing processes are polish grinding with elastic bonded grinding tools and fine grinding with vitrified grinding tools. The process behavior and potential of the different bonds for producing super fine surfaces in generating gear grinding have not been sufficiently scientifically investigated yet. Therefore, the objective of this report is to evaluate these potentials. Part of the investigations are the generating gear grinding process with elastic bonded, as well as vitrified grinding worms with comparable grit sizes. The potential of the different tool specifications is empirically investigated independent of the grain size, focusing on the influence of the bond. One result of the investigations was that the tooth flank roughness could be reduced to nearly the same values with the polish and the fine grinding tool. Furthermore, a dependence of the roughness on the selected grinding parameters could not be determined. However, it was found out that the profile line after polish grinding is significantly dependent on the process strategy used.

Highlights

Due to the continuous increase in required power density, hard fine machining of gears is mandatory in many cases in order to correct deviations from soft machining and heat treatment [1,2]
Continuous generating gear grinding is the dominant process for hard fine machining, for gears with a normal module of up to mn ≤ 8 mm and a number of teeth of z > 20 [5,6,7]
After pre-grinding, grindingtooth investigations were with a vitrified with values of the mean roughness depth of. For both of the grinding tools, grinding worm and polish grinding investigations with a polyurethane bonded grinding it is noted that the right flank has a higher roughness than the left flank

Summary

Introduction

Due to the continuous increase in required power density, hard fine machining of gears is mandatory in many cases in order to correct deviations from soft machining and heat treatment [1,2]. Hard fine machining with undefined cutting edge is an established type of process for achieving high and repeatable gear qualities [5]. Continuous generating gear grinding is the dominant process for hard fine machining, for gears with a normal module of up to mn ≤ 8 mm and a number of teeth of z > 20 [5,6,7]. For gear grinding, vitrified bonding systems are widely used, due to their good profileability and high dimensional stability. Vitrified grinding tools have a high hardness, which is defined as the strength with which the abrasive grain is held by the bond [8]. Metal bonds are available, which are characterized by a high hardness [9].

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Discussion

Conclusion