US Patent 6994514 Turbine blade and gas turbine

Holes 38 and 39 have upstream opening portions 38b and 39b and downstream opening portions 38a and 39a which have a larger cross-sectional area than upstream opening portions 38b and 39b, and are formed at top portion TP of each moving blade. Holes 38 and 39 have tapered shapes T1 and T2 or step portions, and preferably, downstream opening portions 38a and 39a are eccentrically formed toward the moving direction. When tip squealer 37 is formed, hole 38 is formed so that its opening portion is provided at the side surface of tip squealer 37. Without covering the holes for cooling which are formed at the top portion of the turbine blade due to rubbing or the like, the turbine blade is accurately cooled and stably driven.