Patent ID: 7364165

Claim:
A shaft seal mechanism forming a leaf seal in an annular space between a rotor and a stator, comprising: a plurality of thin plates lapped on one another in layers in a circumferential direction of the rotor and arranged in the annular space between the rotor and the stator so as to form a thin plate assembly of an annular shape; and a pair of thin plate retaining rings between which an outer circumferential proximal end side of each of said thin plates is pinched so as to be retained by said retaining rings, wherein said outer circumferential proximal end side of each of said thin plates is supported on a stator side and an inner circumferential distal end side of each of said thin plates is non-fixed to an outer circumferential surface of said rotor so that said thin plate assembly of annular shape divides the annular space into a higher pressure side area and a lower pressure side area; a deviation preventing member arranged between said outer circumferential proximal end side of said thin plates and said thin plate retaining rings so as to regulate motion of each of said thin plates relative to said thin plate retaining rings, wherein said pair of thin plate retaining rings each have an approximate C-shape as seen in a cross-section taken along an axis of rotation and together form concave portions in which said outer circumferential proximal end side of each of said thin plates and said deviation preventing member are fitted so that said thin plate assembly is pressed on its outer circumferential side; wherein said thin plate assembly has side edges on the higher pressure side and the lower pressure side respectively, said side edges being formed with respective annular recesses; side plates provided on the higher pressure side and lower pressure side, respectively, of said thin plate assembly, each of said side plates having a side surface formed with a stepped portion that is engaged with a respective one of said annular recesses on the higher pressure side and the lower pressure side; wherein said side plates on the higher pressure side and the lower pressure side abut said thin plate assembly in the axial direction of said rotor; and said thin plate assembly is pinched together with said side plates between said pair of thin plate retaining rings.