Semitopping shaper cutters Bianco Gianfranco（Semitopping牛头刨床刀比安科詹弗兰科）.pdfVIP

Semi-topping shaper cutters Semi-topping shaper cutter are used during gear cutting to generate chamfers on the tooth tip. The fig.N°1 show clearly the part of the cutter that generate the chamfer. Shaper cutter Semitopping area of cutter Chamfer of the gear Fig. N°1 Not only is it difficult to design and produce these cutters, but it is even more difficult to ensure that the gear chamfer remains constant throughout the life of the shaper cutter. It is impossible to guarantee the constancy of the chamfer on the finished gear not only because of the production tolerances of the teeth (chordal thickness and outside diameter) and the shaper cutter itself, but also because of the profile grinding system. It is well known that the profile is ground according to the angle αR . There are two recognized grinding systems: a)- by fixed grinding wheel (nowadays not often used) b)- by translating grinding wheel. We will now briefly examine the basic features of these two methods. a)- By fixed grinding wheel As can be presumed b the name itself, the wheel axis is maintained immobile in relation to the shaper cutter and therefore the wheel will generate a tooth root whose profile will reflect the curve of the wheel’s outside diameter (see fig. N°2). Fig. N°2 It is obvious that in these cases the gear chamfer will vary greatly, depending on whether the cutter is at the beginning (position 1), at the middle (position 2) or at the end of its life (position 3). From figure N°2 we can see clearly that at beginning of cutter life the chamfer will be large, at the middle of cutter life the chamfer will be small and at the end o