Geared gas turbine engine
First Claim
1. A gas turbine engine comprising a gearbox, the gearbox comprising:
- a sun gear, an annulus gear, a plurality of planet gears, and a carrier,each planet gear being rotatably mounted in the carrier by at least one bearing,the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear,each of the sun gear, the planet gears, and the annulus gear comprising helical gear teeth, the helical gear teeth having a pressure angle and a helix angle,the annulus gear being secured to a surrounding structure by a radially extending member, a face of the radially extending member nearest a middle of the annulus gear being axially spaced from the middle of the annulus gear by a first distance, a reference diameter of the annulus gear being radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance, wherein
the first distance=(the second distance×
sin(the helix angle of the helical gear teeth))/tan (the pressure angle of the helical gear teeth).
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Accused Products
Abstract
A gas turbine engine comprises a gearbox comprising a sun gear, an annulus gear, a plurality of planet gears and a carrier. Each planet gear is rotatably mounted in the carrier by a bearing. The sun gear meshes with the planet gears and the planet gears mesh with the annulus gear. The sun gear, the planet gears and the annulus gear comprise helical gear teeth. The annulus gear is secured to a surrounding structure by a radially extending member. A face of the flange nearest the middle of the annulus gear is axially spaced from the middle of the annulus gear by a first distance. The reference diameter of the annulus gear is radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance. The ratio of first distance to second distance is between and including 0.5 and 1.2 such that misalignment between the annulus gear and the planet gears is reduced to minimise vibrations, noise, stress and wear of the gearbox.
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Citations
20 Claims
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1. A gas turbine engine comprising a gearbox, the gearbox comprising:
a sun gear, an annulus gear, a plurality of planet gears, and a carrier, each planet gear being rotatably mounted in the carrier by at least one bearing, the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear, each of the sun gear, the planet gears, and the annulus gear comprising helical gear teeth, the helical gear teeth having a pressure angle and a helix angle, the annulus gear being secured to a surrounding structure by a radially extending member, a face of the radially extending member nearest a middle of the annulus gear being axially spaced from the middle of the annulus gear by a first distance, a reference diameter of the annulus gear being radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance, wherein
the first distance=(the second distance×
sin(the helix angle of the helical gear teeth))/tan (the pressure angle of the helical gear teeth).- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A gearbox comprising:
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a sun gear, an annulus gear, a plurality of planet gears, and a carrier, each planet gear being rotatably mounted in the carrier by at least one bearing, the sun gear meshing with the planet gears and the planet gears meshing with the annulus gear, each of the sun gear, the planet gears, and the annulus gear comprising helical gear teeth, the annulus gear being secured to a surrounding structure by a radially extending member, a face of the radially extending member nearest a middle of the annulus gear being axially spaced from the middle of the annulus gear by a first distance, a reference diameter of the annulus gear being radially spaced from a point at which the radially extending member is secured to the surrounding structure by a second distance, wherein
the first distance=(the second distance×
sin(helix angle of the helical gear teeth))/tan (pressure angle of the helical gear teeth), anda ratio of the first distance to the second distance is between and including 0.5 and 1.2.
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Specification