Method of fixing blades to axial-flow turbine rotors - by distributing stresses evenly, damping axial vibration, making removal easier

摘要

The rotor (2) has around its periphery axial slots shaped to accept the "fir-tree" (9) blade roots (5), with some clearance. After insertion, the blade root shoulders are peened at each corner (7) to lock them against the rotor (6) and adjacent roots, using a suitably shaped tool (e.g. a pyramid-point punch). This ensures even loading of the blade anchorage and, by the friction between adjacent blade roots, helps to damp out axial blade vibrations. If the rotor rim corners are chamfered before inserting the blades, the locking part of the blade roots shoulders can be machined to facilitate removal.