Impeller for a rotor of a turbomachine, and rotor and turbomachine having an impeller of said type
View Patent ↗An impeller for a rotor of a turbomachine includes: a wheel disc mounted on the rotor, the wheel disc having plural grooves arranged along a circumference of the wheel disc and extending in the thickness direction of the wheel disc. A toothed profile is formed on two sides of each groove. A plurality of impeller blades each have one root with two sides on each of which one toothed profile is formed. Each blade is inserted into a groove so as to form a blade-groove combination with the toothed profiles of the root and of the groove in engagement. Each combination having a fixing device that fixes the blade in the groove in the thickness direction and in the radial direction of the wheel disc. Each fixing device has a recess movably received in the groove base.
1. An impeller ( 20 ) for a rotor ( 10 ) of a turbomachine ( 1 ), the impeller ( 20 ) comprising:
a wheel disc ( 30 ), arranged on a rotor shaft of the rotor ( 10 ) and having a plurality of grooves ( 32 ), the grooves ( 32 ) being arranged so as to be distributed along an outer circumference ( 31 ) of the wheel disc ( 30 ), each of the grooves ( 32 ) having a groove base ( 32 a ), and each of the grooves extending in a thickness direction of the wheel disc ( 30 ) running axially of the rotor shaft, wherein a groove side tooth profile ( 33 ) is formed on two groove sides of each groove ( 32 ) located opposite one another and running parallel to the thickness direction; and
a plurality of moving blades ( 40 ), each having a blade root ( 41 ) with two blade root sides running parallel to the thickness direction and facing away from one another, on each of which a blade root tooth profile ( 43 ) is formed,
wherein each of the moving blades ( 40 ) is configured to form a moving blade-groove combination when inserted with its blade root ( 41 ) into a respective one of the grooves ( 32 ), so that the blade root tooth profiles ( 43 ) of the blade root sides are in engagement with the groove side tooth profiles ( 33 ) of the groove sides,
wherein each moving blade-groove combination comprises a fixing device ( 50 ) configured to fix the moving blade ( 40 ) against movement in the groove ( 32 ) both in the thickness direction as well as in a radial direction (RR) of the wheel disc ( 30 ), and
wherein each fixing device ( 50 ) comprises a recess ( 51 ) closed on both sides at least in the thickness direction in an underside ( 44 ) of the moving blade ( 40 ) facing the groove base ( 32 a ), and a bar ( 52 ) is moveably received in the groove base ( 32 a ) so that the bar ( 52 ) is adjustable in the radial direction (RR) in a controlled manner between an unlocking position, in which the bar ( 52 ) does not engage in the recess ( 51 ) of the moving blade ( 40 ) and a locking position, in which the bar ( 52 ) radially engages in the recess ( 51 ) of the moving blade ( 40 ), so that the bar presses the moving blade ( 40 ) radially to the outside with a predetermined force
wherein each fixing device ( 50 ) in the wheel disc ( 30 ) comprises a first passage ( 53 ) running in the radial direction (RR), which first passage ( 53 ) opens into the groove ( 32 ) on a first longitudinal end ( 53 a ) of said first passage ( 53 ) and into which the bar ( 52 ) is fitted,
wherein each fixing device ( 50 ) comprises an actuating device ( 60 ), arranged on a second longitudinal end ( 53 b ) of the first passage ( 53 ) for the controlled adjusting of the bar ( 52 ), and wherein the actuating device ( 60 ) is configured to be activatable from a side ( 30 a ) of the wheel disc ( 30 ) facing in thickness direction for adjusting the bar ( 52 ),
wherein the actuating device ( 60 ) comprises a second passage ( 61 ), configured in the thickness direction of the wheel disc ( 30 ) running in an internal thread, so that the first passage ( 53 ) with its second longitudinal end ( 53 b ) opens into the second passage ( 61 ) and a first longitudinal end ( 61 a ) of the second passage ( 61 ) opens in the lateral side ( 30 a ) of the wheel disc ( 30 ), and a screw element ( 62 ), which is screwed into the second passage ( 61 ) from the lateral side ( 30 a ) of the wheel disc ( 30 ) and which is operationally connected with a radially innermost end ( 52 b ) of the bar ( 52 ) so that a displacement of the screw element ( 62 ) in thickness direction of the wheel disc ( 30 ) brings about a displacement of the bar ( 52 ) in radial direction, and
wherein a longitudinal end ( 62 a ) of the screw element ( 62 ) provided for the contact with the bar ( 52 ) has a first cone shape and wherein the radially innermost end ( 52 b ) of the bar ( 52 ) has a second cone shape, so that between the respective outer surfaces of the first and of the second cone shape line contact is realized.
2. The impeller ( 20 ) according to claim 1 , wherein the recess ( 51 ) is a depression in the underside ( 44 ) of the moving blade ( 40 ) that is enclosed on all sides by material of the moving blade ( 40 ), and wherein the bar ( 52 ) has a radially outermost end ( 52 a ) configured to engage in the recess ( 51 ) complementarily to the recess ( 51 ).
3. The impeller ( 20 ) according to claim 2 , wherein the recess ( 51 ) is negative to the outer contour of a spherical dome, and wherein the radially outermost end ( 52 a ) of the bar ( 52 ) has a shape corresponding to the outer contour of the spherical dome.
4. The impeller ( 20 ) according to claim 1 , wherein the first cone shape has a cone angle (α) of substantially 20 degrees.
5. A rotor ( 10 ) for a turbomachine ( 1 ), wherein the rotor ( 10 ) comprises at least one impeller ( 20 ) according to claim 1 .
6. A turbomachine ( 1 ) with a rotor ( 10 ), which comprises at least one impeller ( 20 ) according to claim 1 .