Gear and bearing indents to induce fluid film

Patent metadata

Field	Value
Publication number	US-11713716-B2
Application number	US-202117403046-A
Country	US
Kind code	B2
Filing date	Aug 16, 2021
Priority date	Aug 16, 2021
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

A fuel pump assembly for a gas turbine engine includes a shaft for transmitting motion, a gear connected to and coaxial with the shaft with the gear having a first wear surface, a first bearing coaxial with the shaft with the first bearing being configured to support the gear and having a second wear surface positioned to interact with the first wear surface, and a plurality of indents. The indents are distributed in the first wear surface or the second wear surface and at least two of the plurality of indents are partially aligned in a radial direction.

First claim

The invention claimed is:

1. A fuel pump assembly for a gas turbine engine, the fuel pump assembly comprising:
a shaft for transmitting motion;
a gear connected to and coaxial with the shaft, the gear having a first wear surface;
a first bearing coaxial with the shaft, the first bearing being configured to support the gear, wherein the first bearing has a second wear surface positioned to interact with the first wear surface; and
a plurality of indents, wherein each of the indents extends a respective depth into the first wear surface or the second wear surface, at least two of the plurality of indents are partially aligned in a radial direction, and a ratio of an absolute value of a surface area of one of the indents to an absolute value of the depth of the indent is between approximately 0.01 and 0.05.

2. The fuel pump assembly of claim 1 , wherein the first bearing is on a first axial side of the gear and the fuel pump assembly further comprises:
a third wear surface on the gear, wherein the third wear surface is on a second axial side of the gear that is opposite the first wear surface; and
a second bearing coaxial with the shaft, the second bearing being configured to support the gear, wherein the second bearing has a fourth wear surface positioned to interact with the third wear surface, wherein the indents are distributed in the third wear surface or the fourth wear surface.

3. The fuel pump assembly of claim 1 , wherein a total surface area of all the indents occupies between 15 percent and 25 percent of a total surface area of the first wear surface or the second wear surface.

4. The fuel pump assembly of claim 1 , wherein at least one of the indents has a cross-sectional shape selected from the group consisting of a rectangle, triangle, wedge, semicircle, and semi-ellipse.

5. The fuel pump assembly of claim 1 , wherein at least one of the indents has a surface shape selected from the group consisting of a rectangle, circle, triangle, ellipse, oval, and stadium.

6. The fuel pump assembly of claim 1 , wherein each of the indents has a surface shape midpoint in a circumferential direction, and the midpoints of at least two of the indents are aligned in a radial direction.

7. The fuel pump assembly of claim 1 , wherein each of the indents has a surface shape midpoint in a circumferential direction, and the midpoints of at least two of the indents are aligned in the circumferential direction.

8. The fuel pump assembly of claim 1 further comprising:
a fuel between the first wear surface and the second wear surface when the fuel pump assembly is in operation, wherein the indents at least partially control a film thickness of the fuel.

9. An assembly comprising:
a shaft for transmitting motion;
a gear connected to and coaxial with the shaft, the gear having a first wear surface;
a first bearing coaxial with the shaft, the first bearing being configured to support the gear, wherein the first bearing has a second wear surface that interacts with the first wear surface; and
a plurality of indents, wherein a total surface area of all the indents occupies between 15 percent and 25 percent of a total surface area on the first wear surface or the second wear surface, and wherein each of the indents a respective depth into the first wear surface or the second wear surface and a ratio of an absolute value of a surface area of one of the indents to an absolute value of the depth of the indent is between approximately 0.01 and 0.05.

10. The assembly of claim 9 , wherein the first bearing is on a first axial side of the gear and further comprises:
a third wear surface on the gear, wherein the third wear surface is on a second axial side of the gear that is opposite the first wear surface; and
a second bearing coaxial with the shaft, the second bearing being configured to support the gear, wherein the second bearing has a fourth wear surface positioned to interact with the third wear surface, wherein the indents are distributed in the third wear surface or the fourth wear surface.

11. The assembly of claim 9 , wherein at least one of the indents has a cross-sectional shape selected from the group consisting of a rectangle, triangle, wedge, semicircle, and semi-ellipse.

12. The assembly of claim 9 , wherein at least one of the indents has a surface shape selected from the group consisting of a rectangle, circle, triangle, ellipse, oval, and stadium.

13. A method of operating a gear and bearing assembly, the method comprising:
rotating a gear adjacent a bearing configured to support the gear, the gear having a first wear surface positioned to interact with a second wear surface of the bearing, wherein one of the first wear surface and the second wear surface includes a plurality of indents with at least two of the plurality of indents being partially aligned in a radial direction and wherein each of the indents extends a respective depth into one of the first wear surface and the second wear surface and a ratio of an absolute value of a surface area of one of the indents to an absolute value of the depth of the indent is between approximately 0.01 and 0.05; and
generating a fluid film thickness with a fluid between the first wear surface and the second wear surface, wherein during said gear rotation the plurality of indents creates a separation force on the fluid to produce the fluid film thickness.

14. The method of claim 13 , wherein the fluid is a fuel and the method further comprises:
pumping the fuel through the assembly by rotating the gear.

15. The method of claim 13 , wherein a total surface area of all the indents occupies between 15 percent and 25 percent of a total surface area of the first wear surface or the second wear surface.

16. The method of claim 13 , wherein at least one of the indents has a cross-sectional shape selected from the group consisting of a rectangle, triangle, wedge, semicircle, and semi-ellipse.

17. The method of claim 13 , wherein at least one of the indents has a surface shape selected from the group consisting of a rectangle, circle, triangle, ellipse, oval, and stadium.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Goy Edward W
• Ni Weishun William

Classifications

• F02C7/22 Primary

  Fuel supply systems · CPC title

• F04C2/06

  of other than internal-axis type (F04C2/063 takes precedence) · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F04C2/18 Primary

  with similar tooth forms (F04C2/16 takes precedence) · CPC title

• F04C2/084

  Toothed wheels · CPC title