Anti-rotation feature for air turbine starter

An air turbine starter comprising:

• a turbine rotor connected to drive a turbine shaft;
• bearings positioned radially outwardly of said turbine shaft;
• a bearing sleeve positioned radially outwardly of said bearings, and supporting said bearings, said bearing sleeve extending along an axial length defined by a rotational axis of said shaft, and said bearing sleeve having a turbine rotor end adjacent to said turbine rotor, and a remote end;
• a radially outwardly extending flange on said bearing sleeve extending radially outwardly of a support portion of said bearing sleeve and at said turbine rotor end, and said flange having a nominal outer diameter, and including a slot for receiving an anti-rotation tab over a limited circumferential extent;
• a gear cage radially outwardly of said bearing sleeve, and including an anti-rotation tab extending into said slot to resist rotation of said bearing sleeve relative to said gear cage;
• and
• said gear cage is formed of an outer aluminum member having an inner bore, and a steel liner force fit into said inner bore, said tab being part of said steel liner.

A gear cage comprising:

• an outer aluminum member having a cylindrical inner bore;
• a steel liner force fit into said inner bore, a tab being formed as part of said steel liner, and said tab and said outer aluminum member extending along an axial dimension more forwardly than a nominal face of said liner and said outer aluminum member, and over a limited circumferential extent;
• wherein said steel liner has the tab formed in an axially forward end that is to be spaced more toward a turbine rotor than a remote end, and there being an outer diameter of said steel liner, and a ratio of an inner diameter of said forward end to said outer diameter is between 0.92 and 0.98;
• and
• a ratio of said inner diameter of said forward end to an axial length of the entire steel liner is between 12.5 and 4.5.

A bearing sleeve comprising:

• a support portion extending along a central axis, and having a flange at a turbine end extending radially outwardly;
• said flange having a nominal outer radius, and a slot for receiving an anti-rotation lock over a limited circumferential extent, said slot extending over an angle of between 4° and 12° to define said limited circumferential extent;
• and
• said slot extends for a distance along said flat surface between two sides, and a ratio of the distance between said two sides to said nominal radius is between 0.09 and 0.22.

A method of assembling an air turbine starter comprising the steps of:

• inserting a turbine rotor and shaft, and bearings supporting said shaft into a bearing sleeve to form a turbine balance assembly, and said bearing sleeve having a slot to receive an anti-rotation structure at an end of said bearing sleeve positioned toward said turbine rotor;
• moving said turbine balance assembly into a gear cage, said gear cage having an anti-rotation tab and said tab being moved into said slot;
• and
• said gear cage is formed of an outer member having inner bore, and a liner force fit into said inner bore, with said liner providing the tab.