Turbine shaft balancing

Claim 2

In a gas turbine engine having multi-drive shafts including an inner shaft having one end thereof directed exteriorly of the front of the engine to be coupled to a load and an aft end covered by a bearing sump cover and an inner exhaust cone, the improvement comprising: a tubular extension on the inner shaft having an open end thereon for providing access into the interior of the tubular extension, a turbine wheel including a hub located inboard of the bearing sump cover, first bearing means for rotatably supporting said hub so as to support one end of said tubular extension for rotation about its longitudinal axis, second bearing means for rotatably supporting the opposite end of said tubular extension for rotation about said longitudinal axis, said first bearing means including an access opening from the aft end of the engine when the inner exhaust cone and bearing sump cover are removed, a balance tube located interiorly of said tubular extension and being removable through said access opening, a plurality of axially spaced index surfaces formed circumferentially around said balance tube, a balance weight mounted on each of said index surfaces including an outer peripheral surface thereon engageable with the inner surface of said tubular extension to locate said balance tube radially inwardly of the inner surface of said tubular extension concentrically of the longitudinal axis thereof and coacting means on one end of said balance tube and said hub for securing said balance tube axially within said inner shaft and against relative rotation therebetween whereby said inner shaft and balance tube are concurrently driven by said turbine wheel about the longitudinal axis of said shaft, said weights being arcuately adjusted with respect to said balance tube to produce a multi-plane, in-situ balance of the rotating mass of said inner shaft and said turbine wheel coupled in driving relationship therewith.

Claim 3

In a gas turbine engine, the combination of a free turbine shaft having one end adapted to be connected to a load, turbine rotor means connected to the opposite end of said shaft, the opposite end of said shaft being formed as a tubular portion having a first access opening at the aft end thereof, said turbine means including a rotor wheel having an annular hub thereon located in axially spaced relationship to said first access opening, first bearing means for rotatably supporting said rotor hub, second bearing means for rotatably supporting said one end of said shaft whereby said free turbine shaft and said turbine means are rotatably supported with respect to the longitudinal axis of said shaft, said rotor hub defining a second access opening into the tubular portion of said free shaft from the aft end thereof, a balance tube removably supported within said tubular portion of said inner shaft and being removable through said first and second access openings therefrom, said balance tube having a radially outwardly flanged outboard end thereon, means for axially securing said outboard end with respect to said turbine hub to secure said balance tube axially within said free turbine shaft for rotation therewith, said balance tube having a plurality of axially spaced splines formed thereon, each of said axially spaced splines being formed circumferentially around the outer periphery of said balance tube, annular balance weights supported on each of said splines against rotation with respect to said balance tube, each of said weights including an outer peripheral surface thereon engageable with the inner surface of said tubular portion for concentrically aligning said balance tube with respect to the longitudinal axis of said free turbine shaft in radially inwardly spaced relationship to the inner surface of said tubular portion, one of said weights being located at one end of said tubular portion, another of said weights being located at the flanged end of said balance tube and having the outer periphery thereof engageable with said rotor hub, an intermediate balance weight located between said tubular portion and said balance tube for concentrically locating the balance tube intermediate the ends thereof with respect to the longitudinal axis of said free turbine shaft, said weights being configured to produce a multi-plane in-situ balance of dynamic imbalance in said free turbine shaft and said turbine means connected thereto.

Claim 4

In a gas turbine engine, the combination of a free turbine shaft having one end adapted to be connected to a load, turbine rotor means connected to the opposite end of said shaft, the opposite end of said shaft being formed as a tubular portion having a first access opening at the aft end thereof, said turbine means including a rotor wheel having an annular hub thereon located in axially spaced relationship to said first access opening, first bearing means for rotatably supporting said rotor hub, second bearing means for rotatably supporting said one end of said shaft whereby said free turbine shaft and said turbine means are rotatably supported with respect to the longitudinal axis of said shaft, said rotor hub defining a second access opening into the tubular portion of said free shaft from the aft end thereof, a balance tube removably supported within said tubular portion of said inner shaft and being removable through said first and second access openings therefrom, said balance tube having a radially outwardly flanged outboard end thereon, means for axially securing said outboard end with respect to said turbine hub to secure said balance tube axially within said free turbine shaft for rotation therewith, said balance tube having a plurality of axially spaced splines formed thereon, each of said axially spaced splines being formed circumferentially around the outer periphery of said balance tube, annular balance weights supported on each of said splines against rotation with respect to said balance tube, each of said weights including an outer peripheral surface thereon engageable with the inner surface of said tubular portion for concentrically aligning said balance tube with respect to the longitudinal axis of said free turbine shaft in radially inwardly spaced relationship to the inner surface of said tubular portion, one of said weights being located at one end of said tubular portion, another of said weights being located at the flanged end of said balance tube and having the outer periphery thereof engageable with said rotor hub, an intermediate balance weight located between said tubular portion and said balance tube for concentrically locating the balance tube intermediate the ends thereof with respect to the longitudinal axis of said free turbine shaft, said weights being configured to produce a multi-plane in-situ balance of dynamic imbalance in said free turbine shaft and said turbine means connected thereto.

Claim 5

A turbine drive assembly comprising a turbine wheel having a ring of vanes for reaction with exhaust flow from a gas turbine engine, a free turbine shaft having a tubular extension thereon, means for rotatably supporting one end of said tubular extension, said means including means adapted to be connected to a load, means coupling the opposite end of said tubular extension to said turbine wheel, said turbine wheel having a hub portion thereon defining a central bore therethrough to provide access into the interior of said tubular extension, said hub having an outer peripheral bearing surface thereon, bearing means on said surface for rotatably supporting said rotor hub and the opposite end of said tubular shaft extension for rotation about the longitudinal axis of said shaft, means for balancing said shaft and wheel including an elongated balance tube removably supported within said tubular extension through said central bore, said balance tube having a radially outwardly directed flange on one end thereof, means for securing said flange to said hub against axial movement with respect thereto when the balance tube is in place within said tubular extension, said balance tube member having a plurality of axially spaced lands thereon located radially inwardly from the inner surface of said tubular extension, an annular balance weight removably secured on each of said lands including peripheral wall means thereon in engagement with said shaft to maintain said tube concentrically within said shaft, means for arcuately adjusting each of said weights to said tube member to produce a multi-plane in-situ balance of said shaft and turbine wheel.

Claim 6

A turbine drive assembly comprising a turbine wheel having a ring of vanes for reaction with exhaust flow from a gas turbine engine, a free turbine shaft having a tubular extension thereon, means for rotatably supporting one end of said tubular extension, said means including means adapted to be connected to a load, means coupling the opposite end of said tubular extension to said turbine wheel, said turbine wheel having a hub portion thereon defining a central bore therethrough to provide access into the interior of said tubular extension, said hub having an outer peripheral bearing surface thereon, bearing means on said surface for rotatably supporting said rotor hub and the opposite end of said tubular shaft extension for rotation about the longitudinal axis of said shaft, means for balancing said shaft and wheel including an elongated balance tube removably supported within said tubular extension through said central bore, said balance tube having a radially outwardly directed flange on one end thereof, means for securing said flange to said hub against axial movement with respect thereto when the balance tube is in place within said tubular extension, said balance tube member having a plurality of axially spaced lands thereon located radially inwardly from the inner surface of said tubular extension, an annular balance weight removably secured on each of said lands including peripheral wall means thereon in engagement with said shaft to maintain said tube concentrically within said shaft, means for arcuately adjusting each of said weights to said tube member to produce a multi-plane in-situ balance of said shaft and turbine wheel.

Claim 7

A balanced turbine drive assembly comprising: a hollow free turbine shaft, a turbine wheel connected to one end of said shaft having a central opening therethrough to define an outboard access interiorly of said shaft, means for supporting said rotor wheel for rotation about the longitudinal axis of said shaft, means for rotatably supporting the other end of said free turbine shaft, a plurality of axially spaced reference surfaces on the interior of said hollow shaft, a balance tube located within said hollow shaft removable exteriorly thereof through said central opening in said turbine wheel, and a plurality of annular balance weights secured to said tube each including an outer peripheral surface thereon engageable with said spaced reference surfaces to position said balance tube concentrically within said hollow free turbine shaft with the longitudinal axis of said balance tube being colinear with the longitudinal axis of said free turbine shaft, and coacting means for arcuately adjusting each of said annular balance weights on said balance tube to maintain a multi-plane in-situ balance of said free turbine shaft and said turbine wheel that can be adjusted by withdrawing said balance tube and arcuately adjusting said balance weights thereon.

Claim 8

A balanced turbine drive assembly comprising: a hollow free turbine shaft, a turbine wheel connected to one end of said shaft having a central opening therethrough to define an outboard access interiorly of said shaft, means for supporting said rotor wheel for rotation about the longitudinal axis of said shaft, means for rotatably supporting the other end of said free turbine shaft, a plurality of axially spaced reference surfaces on the interior of said hollow shaft, a balance tube located within said hollow shaft removable exteriorly thereof through said central opening in said turbine wheel, and a plurality of annular balance weights secured to said tube each including an outer peripheral surface thereon engageable with said spaced reference surfaces to position said balance tube concentrically within said hollow free turbine shaft with the longitudinal axis of said balance tube being colinear with the longitudinal axis of said free turbine shaft, and coacting means for arcuately adjusting each of said annular balance weights on said balance tube to maintain a multi-plane in-situ balance of said free turbine shaft and said turbine wheel that can be adjusted by withdrawing said balance tube and arcuately adjusting said balance weights thereon.

Claim 9

A balanced turbine drive assembly comprising: a hollow free turbine shaft, a turbine wheel connected to one end of said shaft having a central opening therethrough to define an outboard access interiorly of said shaft, means for supporting said rotor wheel for rotation about the longitudinal axis of said shaft, means for rotatably supporting the other end of said free turbine shaft, a plurality of axially spaced reference surfaces on the interior of said hollow shaft, a balance tube located within said hollow shaft removable exteriorly thereof through said central opening in said turbine wheel, means engageable with said spaced reference surfaces to position said balance tube concentrically within said hollow free turbine shaft with the longitudinal axis of said balance tube being colinear with the longitudinal axis of said free turbine shaft, a plurality of annular balance weights on said tube, and coacting means on said tube and said weights for arcuately adjusting each of said annular balance weights on said balance tube to maintain a multi-plane in-situ balance of said free turbine shaft and said turbine wheel that can be adjusted by withdrawing said balance tube and arcuately adjusting said balance weights thereon.

Claim 10

A balanced turbine drive assembly comprising: a hollow free turbine shaft, a turbine wheel connected to one end of said shaft having a central opening therethrough to define an outboard access interiorly of said shaft, means for supporting said rotor wheel for rotation about the longitudinal axis of said shaft, means for rotatably supporting the other end of said free turbine shaft, a plurality of axially spaced reference surfaces on the interior of said hollow shaft, a balance tube located within said hollow shaft removable exteriorly thereof through said central opening in said turbine wheel, means engageable with said spaced reference surfaces to position said balance tube concentrically within said hollow free turbine shaft with the longitudinal axis of said balance tube being colinear with the longitudinal axis of said free turbine shaft, a plurality of annular balance weights on said tube, and coacting means on said tube and said weights for arcuately adjusting each of said annular balance weights on said balance tube to maintain a multi-plane in-situ balance of said free turbine shaft and said turbine wheel that can be adjusted by withdrawing said balance tube and arcuately adjusting said balance weights thereon.