The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 30, 1996
Filed:
Oct. 11, 1994
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In an axial-flow turbine, at least one of front and rear side contact surfaces of shrouds (3a or 3b) of blades (1a or 1b) with respect to the turbine rotational direction is formed at certain angle with respect to a radial line connecting the rotor center and the contact surface. The shroud (3a) of the blade (1a) of a first kind is formed in a trapezoidal shape converging radially outward in cross section taken in a plane perpendicular to the turbine axial direction, and the shroud (3b) of the blade (1b) of a second kind is formed in an inverted trapezoidal shape converging radially inward in the cross section. Further, half of an angle (2.alpha.) between the front and rear side contact surfaces of the shrouds (3a or 3b) is made smaller than a static frictional angle of the contact surface. Since the shroud contact surfaces of two adjacent blades can be kept in pressure contact with each other under all operating conditions, a large dynamic stress reduction and superior damping properties can be obtained without producing excessive initial stresses at the blade airfoil and blade dovetail attachment portion.