Flexible coupling for geared turbine engine
First Claim
Patent Images
1. A gas turbine engine comprising:
- a fan shaft arranged along an engine central axis;
a frame supporting the fan shaft, the frame defining a frame lateral stiffness;
a gear system rotatably coupled to the fan shaft, the gear system having a gear reduction ratio that is greater than 2.3; and
a first, non-rotatable flexible coupling and a second, rotatable flexible coupling supporting the gear system, the first flexible coupling and the second flexible coupling being subject to, with respect to the engine central axis, parallel offset guided end motion,the second flexible coupling having a stiffness (D) that is torsional stiffness under the parallel offset guided end motion, and the second flexible coupling has a ratio of the frame lateral stiffness to the torsional stiffness that is in a range of 2 to 100.
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Abstract
A gas turbine engine includes a fan shaft arranged along an engine central axis, a frame supporting the fan shaft, a gear system rotatably coupled with the fan shaft, and a flexible coupling at least partially supporting the gear system. The flexible coupling defines, with respect to the engine central axis, a torsional stiffness TS and a lateral stiffness LS such that a ratio of TS/LS is greater than or equal to about 2.0 to reduce loads on the gear system from misalignment of the gear system with respect to the engine central axis.
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Citations
26 Claims
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1. A gas turbine engine comprising:
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a fan shaft arranged along an engine central axis; a frame supporting the fan shaft, the frame defining a frame lateral stiffness; a gear system rotatably coupled to the fan shaft, the gear system having a gear reduction ratio that is greater than 2.3; and a first, non-rotatable flexible coupling and a second, rotatable flexible coupling supporting the gear system, the first flexible coupling and the second flexible coupling being subject to, with respect to the engine central axis, parallel offset guided end motion, the second flexible coupling having a stiffness (D) that is torsional stiffness under the parallel offset guided end motion, and the second flexible coupling has a ratio of the frame lateral stiffness to the torsional stiffness that is in a range of 2 to 100. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A gas turbine engine comprising:
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a fan; a fan shaft coupled with the fan and arranged along an engine central axis; an input shaft; a high pressure turbine and a low pressure turbine, the low pressure turbine having a pressure ratio of greater than 5; a frame supporting the fan shaft, the frame defining a frame lateral stiffness; a gear system rotatably coupled with the fan shaft and also rotatably coupled with the low pressure turbine through the input shaft; and a first, non-rotatable flexible coupling and a second, rotatable flexible coupling supporting the gear system, the first flexible coupling and the second flexible coupling being subject to, with respect to the engine central axis, parallel offset guided end motion, the second flexible coupling having a stiffness (D) that is torsional stiffness under the parallel offset guided end motion, and the second flexible coupling has a ratio of the frame lateral stiffness to the torsional stiffness that is in a range of 2 to 100. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A gas turbine engine comprising:
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a fan shaft arranged along an engine central axis; a frame supporting the fan shaft, the frame defining a frame lateral stiffness; a gear system rotatably coupled to the fan shaft, the gear system including a sun gear in meshed engagement with multiple intermediate gears that are rotatably mounted on bearings in a non-rotatable carrier, each intermediate gear in meshed engagement with a rotatable ring gear, and the sun gear rotatably coupled to the fan shaft; and a first, non-rotatable flexible coupling and a second, rotatable flexible coupling supporting the gear system, the first flexible coupling and the second flexible coupling being subject to, with respect to the engine central axis, parallel offset guided end motion, the second flexible coupling having a stiffness (D) that is torsional stiffness under the parallel offset guided end motion, and the second flexible coupling has a ratio of the frame lateral stiffness to the torsional stiffness that is in a range of 2 to 100. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A gas turbine engine comprising:
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a fan shaft arranged along an engine central axis; a frame supporting the fan shaft, the frame defining a frame lateral stiffness; a gear system rotatably coupled to the fan shaft, the gear system including a sun gear in meshed engagement with multiple intermediate gears that are rotatably mounted on bearings in a rotatable carrier, each intermediate gear in meshed engagement with a non-rotatable ring gear, and the sun gear rotatably coupled to the fan shaft; and a first, non-rotatable flexible coupling and a second, rotatable flexible coupling supporting the gear system, the first flexible coupling and the second flexible coupling being subject to, with respect to the engine central axis, parallel offset guided end motion, the second flexible coupling having a stiffness (D) that is torsional stiffness under the parallel offset guided end motion, and the second flexible coupling has a ratio of the frame lateral stiffness to the torsional stiffness that is in a range of 2 to 100. - View Dependent Claims (22, 23, 24, 25, 26)
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Specification