Patent ID: 7481625

Claim:
A radial-flow turbine wheel for a gas turbine, the radial-flow turbine wheel comprising: a hub having a generally cylindrical front end, an intermediate portion with an outer radius generally increasing from the front end to a rear end, the rear end of the hub having an enlarged outer periphery; a plurality of turbine blades formed around the hub at constant intervals, the turbine blades rotating the radial-flow turbine wheel powered by expansion of an operating fluid of high temperature and high pressure; and a plurality of elongate narrow slots, each of the elongate slots formed in a generally radial direction at a central and radially outmost edge of the enlarged outer periphery of the hub between two adjacent ones of the turbine blades for suppressing creation and propagation of cracks in the hub due to thermal stress by operation of the turbine wheel, the elongate slots formed in the enlarged outer periphery of the hub without reinforcing the outer periphery of the hub with an expanded outer rim, each of the elongate slots having a predetermined depth of at least 3 mm from the central and radially outmost edge of the enlarged outer periphery of the hub, an inner end of each of the elongate slots having an enlarged opening.