Spline gear reciprocating lapping machie

Abstract

An apparatus is presented which will automatically lap involute and strai internal or external gear splines. Lapping force is applied alternatively to the left and right side of each tooth flank. Automatic indexing to new radial positions about the circumference of a gear after any preselected number of lapping cycles accomplishes the application of equal lapping forces to each tooth. The apparatus comprises a bed or support frame upon which is mounted a headstock assembly and a tailstock assembly. Mating workpieces, e.g., mating involute or straight internal or external gear splines, are fastened through collets to the mechanisms of the headstock and tailstock assemblies. The tailstock assembly includes a mainshaft attached to the collet holding its workpiece. The mainshaft is driven by a pneumatic piston to reciprocate along the axis of the workpiece causing the workpieces to lap one another. Equal lapping force to each tooth flank is maintained during lapping cycles by a clutch mechanism which transfers a torque along the mainshaft to the workpiece held by the mainshaft as it laps against its mating workpiece held by the headstock assembly. The headstock assembly consists of a transmission which is connected to an indexing mechanism which, between each separate lapping operation, will rotate the workpiece held by the headstock collet an angular distance equal to one tooth spacing. Rotation through increments of one tooth spacing occur automatically after each individual lapping operation until the mating gears have been lapped against one another in all possible orientations between their respective teeth positions. The apparatus produces smooth and consistent gear tooth finishes in a rapid time since the lapping machine maintains proper centerline alignment between mating spline parts throughout all phases of the lapping operations.