Influence of the number of replaceable gears on setup errors in gear-milling machines

Abstract

In gear production, machining of the teeth is an important stage. In this context, we may note the introduction of new toothmachining technologies, constant improvement in machinetool design, and the use of more productive cutting tools. Reduction in the time for machinetool preparation and adjustment is of particular importance in order to permit complete automation of gear production. A promising approach here is the use of numerically controlled tooth� machining systems with continuous regulation. Most machine tools at Russian enterprise incorpo� rate complex kinematic groups and only permit step� wise regulation. Adjustment of the burnishing and split� ting systems and the differential relies on kinematic mechanisms in the form of replaceableear frames. Adjustment error may result in incompatible motion of the working components and interfere with the tool's trajectory relative to the blank. The outcome in that case would be distortion of the machined surface. Besides these deficiencies associated with adjustment errors, such machine tools have certain benefits—nota� bly, simple design and operational reliability. The selection of the replaceable gears involves determining the number of gear teeth so as to ensure the required gear ratio. Each frame in the machine tool is equipped with a particular set of replaceable gears. The number of gears in the set and the numbers of teeth in the gears will be different. They depend on the possible range of gear ratios (in machinetool operation) and the precision of gearratio selection. In operation, some of the replaceable gears may mal� function or may be used in other frames within the dif� ferential. Therefore, some of the selected gears may be unavailable. The basic set of gears supplied with the machine tool may be supplemented with new gears characterized by different numbers of teeth; this reduces the adjustment error.