Device for fastening a moving blade to the rotor of a turbomachine

Abstract

A device for fastening a moving blade ( 3 ) to a rotor ( 2 ) of a thermal turbomachine is described. The moving blade ( 3 ) has a blade root ( 36 ), a blade leaf ( 32 ) and a platform ( 31 ) arranged between the blade root ( 36 ) and the blade leaf ( 32 ) and having at least two side flanks ( 33, 34 ). The idea, on which the invention is based, of avoiding axial forces occurring on the rotor ( 2 ) on account of bearing faces set obliquely to the rotor axis ( 4 ) between two adjacent moving blades ( 3 ) is that adjacent moving blades ( 3 ) meet solely at axially oriented bearing faces ( 52 ).

1 . A device for fastening moving blades ( 3 ) along a circumferential groove ( 1 ) running within a rotor ( 2 ) of a thermal turbomachine, in which 
 the moving blades ( 3 ) have a blade root ( 36 ), a blade leaf ( 32 ) and a platform ( 31 ) arranged between the blade root ( 36 ) and the blade leaf ( 32 ) and having at least two side flanks ( 33 ,  34 ),    the circumferential contour ( 1 ) provides an inner contour designed for receiving the blade roots ( 36 ), and    the side flanks ( 33 ,  34 ) of the platform ( 31 ) of the moving blades ( 3 ) located in the circumferential groove are inclined obliquely to the rotor axis ( 4 ), characterized in that,    in the region of the blade root ( 36 ) extending into the circumferential groove ( 1 ), bearing faces ( 52 ) are provided which are actively connected to said blade root and are oriented parallel to the rotor axis ( 4 ), and    adjacently inserted moving blades ( 3 ) come into a loose force-exposed connection directly or indirectly with one another, in each case within the circumferential groove ( 1 ), via the bearing faces ( 52 ) oriented parallel to the rotor axis ( 4 ).    
     
     
         2 . The device as claimed in  claim 1 , characterized in that an intermediate gap ( 7 ), in which is introduced a shim ( 5 ) having the bearing faces ( 52 ), is provided radially within the circumferential groove ( 1 ) between the blade root ( 36 ) and the rotor ( 2 ), the shim ( 5 ) extending beyond the two side flanks ( 33 ,  34 ) in the circumferential direction.  
     
     
         3 . The device as claimed in  claim 2 , characterized in that the shim ( 5 ) has a connection means ( 6 ) by which the shim ( 5 ) is capable of being connected releasably firmly to the blade root ( 36 ).  
     
     
         4 . The device as claimed in  claim 3 , characterized in that the connection means ( 6 ) is a force-exposed bolt ( 61 ) which engages from the sides of the shim ( 5 ) into a recess ( 64 ) provided correspondingly within the blade root ( 36 ).  
     
     
         5 . The device as claimed in  claim 2 , characterized in that the shim ( 5 ) is joined firmly to the blade root ( 36 ) or is connected in one piece to the blade root ( 36 ).  
     
     
         6 . The device as claimed in one of  claims 2  to  5 , characterized in that the shim ( 5 ) is designed in the manner of an “H”, the connecting limb ( 51 ) of which is oriented essentially parallel to the side flanks ( 33 ,  34 ) of the platform ( 31 ) and has four bearing faces ( 52 ) oriented parallel to the rotor axis ( 4 ).  
     
     
         7 . The device as claimed in one of  claims 1  to  6 , characterized in that, in the state in which the moving blade ( 3 ) is joined to the rotor ( 2 ), that surface of the platform ( 31 ) which is directed radially to the blade leaf ( 32 ) is flush with said rotor.  
     
     
         8 . The device as claimed in one of  claims 1  to  7 , characterized in that an intermediate piece which is flush with the rotor ( 2 ) is inserted between two adjacent moving blades ( 3 ) into the circumferential groove ( 1 ) and fits snugly, essentially free of force, against the side flanks ( 33 ,  34 ) of the platform ( 31 ) of the two adjacent moving blades ( 3 ).  
     
     
         9 . The device as claimed in one of  claims 1  to  8 , characterized in that the platform ( 31 ) has a rhombically designed shape in which the side flanks ( 33 ,  34 ) extend along the width of the blade leaf ( 32 ).  
     
     
         10 . The device as claimed in one of  claims 1  to  9 , characterized in that at least one intermediate piece is inserted between two adjacent moving blades ( 3 ) within the circumferential groove ( 1 ) and has a blade root ( 36 ) and also a platform ( 31 ) which is flush with the rotor ( 2 ) and with the platforms ( 31 ) of two adjacent moving blades ( 3 ).