Geared turbofan with overspeed protection

1. A gas turbine engine comprises:

a fan drive turbine driving a gear reduction, said gear reduction, in turn, driving a fan rotor, said fan rotor delivering air into a bypass duct as bypass air and into a compressor section as core flow;

a forward bearing positioned between said gear reduction and said fan rotor and supporting said gear reduction, and a second bearing positioned aft of said gear reduction and supporting said gear reduction, and said second bearing being a thrust bearing; and

a fan drive turbine drive shaft driving said gear reduction, and said fan drive turbine drive shaft having a weakened link which is aft of said second bearing such that said fan drive turbine drive shaft will tend to fail at said weakened link, and at a location aft of said second bearing.

2. The gas turbine engine as set forth in claim 1 , wherein said compressor section includes a low pressure compressor and a high pressure compressor and said low pressure compressor also being driven by said gear reduction to rotate with said fan.

3. The gas turbine engine as set forth in claim 1 , wherein said compressor section including a low pressure compressor and a high pressure compressor and said low pressure compressor being driven at a common speed by said fan drive turbine drive shaft.

4. The gas turbine engine as set forth in claim 1 , wherein said compressor section including a low pressure compressor and a high pressure compressor and said second bearing being positioned intermediate said low pressure compressor and said high pressure compressor.

5. The gas turbine engine as set forth in claim 1 , wherein a catcher is provided between said gear reduction and said fan rotor to resist movement of said gear reduction and said fan rotor in an outer direction in the event of a failure of a fan rotor bearing.

6. The gas turbine engine as set forth in claim 5 , wherein said gear reduction is an epicyclic gear reduction.

7. The gas turbine engine as set forth in claim 6 , wherein said epicyclic gear reduction includes a sun gear driving intermediate gears, a static ring gear, and a carrier rotating when driven by said sun gear, said carrier being attached to a fan drive shaft to drive said fan rotor, and said catcher includes a member attached to a static structure and having a radially inner end forward of a flange on said fan drive shaft, and said catcher being contacted by said flange should said gear reduction move in a forward direction, to resist movement of said gear reduction.

8. The gas turbine engine as set forth in claim 6 , wherein said epicyclic gear reduction includes a sun gear, intermediate gears driven by said sun gear, and a ring gear driven by said intermediate gears, with a static carrier, and said ring gear driving said fan drive shaft, said catcher including a member having a radially outer location positioned forwardly of a radially inwardly extending flange which rotates with said fan drive shaft, said catcher being contacted by said radially inwardly extending flange should said gear reduction move in a forward direction, said catcher to resist movement of said gear reduction.

9. The gas turbine engine as set forth in claim 8 , wherein said catcher is formed of two parts with an intermediate gap.

10. The gas turbine engine as set forth in claim 1 , wherein said gear reduction is an epicyclic gear reduction.

11. A gas turbine engine comprises:

a fan drive turbine driving a gear reduction, said gear reduction, in turn, driving a fan rotor, said fan rotor delivering air into a bypass duct as bypass air and into a compressor section as core flow;

a forward bearing positioned between said gear reduction and said fan rotor and supporting said gear reduction, and a second bearing positioned aft of said gear reduction and supporting said gear reduction, and said second bearing being a thrust bearing;

a fan drive turbine drive shaft driving said gear reduction;

a catcher provided to resist movement of said gear reduction and said fan rotor in an outer direction in the event of a failure of said second bearing said catcher being between said gear reduction and said fan rotor;

said gear reduction is an epicyclic gear reduction; and

wherein said catcher is formed of two parts with an intermediate gap.

12. The gas turbine engine as set forth in claim 11 , wherein said epicyclic gear reduction includes a sun gear driving intermediate gears, a static ring gear, and a carrier rotating when driven by said sun gear, said carrier being attached to a fan drive shaft to drive said fan rotor.

13. The gas turbine engine as set forth in claim 12 , wherein said catcher includes a member having a radially inner location positioned forwardly of a radially outwardly extending flange which rotates with said fan drive shaft, said catcher being contacted by said radially outwardly extending flange should said gear reduction move in a forward direction, said catcher to resist movement of said gear reduction.

14. The gas turbine engine as set forth in claim 11 , wherein said compressor section includes a low pressure compressor and a high pressure compressor and said low pressure compressor also being driven by said gear reduction to rotate with said fan.

15. The gas turbine engine as set forth in claim 14 , wherein said second bearing being positioned intermediate said low pressure compressor and said high pressure compressor.

16. The gas turbine engine as set forth in claim 11 , wherein said compressor section including a low pressure compressor and a high pressure compressor and said low pressure compressor being driven at a common speed by said fan drive turbine drive shaft.

17. The gas turbine engine as set forth in claim 11 , wherein said compressor section including a low pressure compressor and a high pressure compressor and said second bearing being positioned intermediate said low pressure compressor and said high pressure compressor.