The energetic load smoothing along the rack tool cutting edge in toothing process

Abstract

Abstract. The method of generating the gear tooth with a rack tool is applied on MAAG machine tools. Their specific cutting scheme leads to an irregular energetic loading of the tool cutting edge, during the rolling process. In this paper, we present a new method for analyzing the energetic load along the cutting edges of the rack shaped cutter, based on graphical modelling of the cutting process performed in CATIA. The energetic load smoothing is proposed to be obtained by finding an appropriate variation law for the circular feed communicated to the workpiece by toothing machine kinematical chain, during the rolling motion that permanently respects the rolling condition established between the centrodes attached to both tool and workpiece. A numerical solution in a concrete case of analysis is also included.

Detached chip smoothing during involute gear slotting in relation to generated tooth features

“…The area of the chip detached at each active stroke of the rack shaped cutter can be found by graphical modelling the toothing process in CATIA. The method dedicated to this purpose, presented in [5], has been comparatively applied in three different cases of gears, having the same module, m = 10 mm, teeth number being z 1 = 30, z 2 = 45 and z 3 = 60, hence the corresponding rolling radii R r were 150, 225 and 300 mm, respectively. The variation law of detached chip area, if machining with constant feed speed, has been found at first, in all three cases.…”

“…The results are sampled, in numerical form, in Table 1 (detached chip areas for first 10 double strokes) and completely presented, in graphical form, in Figure 3. After that, the algorithm for cutting process smoothing [5] has been applied, in all three cases also, and the variation laws of the nonuniform circular feed (which always remains strictly correlated, according to condition (1), with rack shaped tool linear feed,) results as depicted in Figure 4. The maximum circular…”

“…The problem of finding the variation law for the energetic load of the rack shaped cutter when generating, by rolling method, the straight teeth of gears with involute profile has already been addressed in two different approaches concerning the toothing process smoothing by modifying the detached chip area. The first approach lies on changing the constructive shape of the rack-tool [4], while the second grounds on varying the rolling motion speed, according to an appropriate law, which enables to obtain a quasiconstant area of the detached chip [5]. The aspects of the problem defined and developed by [5] in the case of a mono-tooth rack shaped tool, which generates in a single pass the entire space between the flanks of two successive teeth, should be extended for gears having diverse numbers of teeth and, at the same time, to the situation when generating involute gears by multiple, successive passes.…”

“…The first approach lies on changing the constructive shape of the rack-tool [4], while the second grounds on varying the rolling motion speed, according to an appropriate law, which enables to obtain a quasiconstant area of the detached chip [5]. The aspects of the problem defined and developed by [5] in the case of a mono-tooth rack shaped tool, which generates in a single pass the entire space between the flanks of two successive teeth, should be extended for gears having diverse numbers of teeth and, at the same time, to the situation when generating involute gears by multiple, successive passes. This can be done by appealing to the principles of generating surfaces by enwrapping [6][7][8], but also by taking advantage from the facilities of the graphical design environments, such as CATIA.…”