Gearbox assembly
View Patent ↗A gearbox assembly includes a first gear and a second gear. The first gear includes a plurality of first gear teeth. The second gear includes a plurality of second gear teeth. The plurality of first gear teeth and the plurality of second gear teeth mesh with each other as the first gear and the second gear rotate. A profile shape of at least one first gear tooth of the first gear is characterized by a total profile modification between 66 micrometers and 120 micrometers.
1. A gearbox assembly comprising:
a first gear comprising a plurality of first gear teeth; and
a second gear comprising a plurality of second gear teeth, the plurality of first gear teeth and the plurality of second gear teeth meshing with each other as the first gear and the second gear rotate,
wherein a profile shape of at least one first gear tooth of the first gear is characterized by a total profile modification between 66 micrometers and 120 micrometers, wherein the total profile modification includes a profile tip relief and a helix relief of the at least one first gear tooth.
2. The gearbox assembly of claim 1 , wherein the total profile modification is between 68 micrometers and 90 micrometers.
3. The gearbox assembly of claim 1 , wherein the at least one first gear tooth extends from a root to a tip and includes a first end face and a second end face opposite the first end face, and a first axial face and a second axial face opposite the first axial face that extend from the first end face to the second end face, and wherein the total profile modification is zero at a radial center and a helix axial center of the first axial face of the at least one first gear tooth.
4. The gearbox assembly of claim 3 , wherein the total profile modification is a maximum at the root and the tip of the at least one first gear tooth, and at the first end face and the second end face of the at least one first gear tooth.
5. The gearbox assembly of claim 1 , wherein the gearbox assembly is coupled to a fan of a turbine engine, and the total profile modification is a function of a torque of the fan, a gear ratio of the gearbox assembly, a pitch diameter of the first gear, and a number of meshes of the first gear with the second gear.
6. The gearbox assembly of claim 5 , wherein the total profile modification is a function of a stiffness per unit length of the at least one first gear tooth, a mesh contact ratio of the first gear and the second gear, and a unit length of contact between the at least one first gear tooth and a respective second gear tooth.
7. The gearbox assembly of claim 6 , wherein the total profile modification is greater than or equal to
(
(
T
fan
Gear
ratio
)
Pitch
Diameter
Number
of
Meshes
)
(
3.2
K
max
εγ
X
0
)
wherein T fan is the torque of the fan, K max is the stiffness per unit length in Newtons per millimeters micrometers, εγ is the mesh contact ratio, and X 0 is the unit length of contact in millimeters.
8. The gearbox assembly of claim 7 , wherein K max is between 13 Newtons per millimeter micrometer and 19 Newtons per millimeter micrometer.
9. The gearbox assembly of claim 7 , wherein εγ is between 2.3 and 5.
10. The gearbox assembly of claim 7 , wherein X 0 is between 2.5 millimeters and 5.5 millimeters.
11. A turbine engine comprising:
a fan including a fan rotor;
an engine core including a shaft assembly; and
a gearbox assembly comprising:
a first gear coupled to the shaft assembly of the engine core, the first gear comprising a plurality of first gear teeth; and
a second gear coupled to the fan rotor of the fan, the second gear comprising a plurality of second gear teeth, the plurality of first gear teeth and the plurality of second gear teeth meshing with each other as the first gear and the second gear rotate,
wherein a profile shape of at least one first gear tooth of the first gear is characterized by a total profile modification between 66 micrometers and 120 micrometers, and wherein the total profile modification includes a profile tip relief and a helix relief of the at least one first gear tooth.
12. The turbine engine of claim 11 , wherein the total profile modification is between 68 micrometers and 90 micrometers.
13. The turbine engine of claim 11 , wherein the at least one first gear tooth extends from a root to a tip and includes a first end face and a second end face opposite the first end face, and a first axial face and a second axial face opposite the first axial face that extend from the first end face to the second end face, and wherein the total profile modification is zero at a radial center and a helix axial center of the first axial face of the at least one first gear tooth.
14. The turbine engine of claim 13 , wherein the total profile modification is a maximum at the root and the tip of the at least one first gear tooth, and at the first end face and the second end face of the at least one first gear tooth.
15. The turbine engine of claim 11 , wherein the total profile modification is a function of a torque of the fan, a gear ratio of the gearbox assembly, a pitch diameter of the first gear, and a number of meshes of the first gear with the second gear.
16. The turbine engine of claim 15 , wherein the total profile modification is a function of a stiffness per unit length of the at least one first gear tooth, a mesh contact ratio of the first gear and the second gear, and a unit length of contact between the at least one first gear tooth and a respective second gear tooth.
17. The turbine engine of claim 16 , wherein the total profile modification is greater than or equal to
(
(
T
fan
Gear
ratio
)
Pitch
Diameter
Number
of
Meshes
)
(
3.2
K
max
εγ
X
0
)
wherein T fan is the torque of the fan, K max is the stiffness per unit length in Newtons per millimeters micrometers, εγ is the mesh contact ratio, and X 0 is the unit length of contact in millimeters.
18. The turbine engine of claim 17 , wherein K max is between 13 Newtons per millimeter micrometer and 19 Newtons per millimeter micrometer.
19. The turbine engine of claim 17 , wherein εγ is between 2.3 and 5.
20. The turbine engine of claim 17 , wherein X 0 is between 2.5 millimeters and 5.5 millimeters.