# US 2019/0316629 A1 · Air bearing with surface layer

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- Number: US 2019/0316629 A1
- Document ID: US20190316629A1
- Status: Published application
- Kind: A1
- Application number: 15/952,730
- Filed: 2018-04-13
- Published: 2019-10-17
- Earliest claimed: 2018-04-13
- Assignees: Hamilton Sundstrand Corporation
- Applicants: Hamilton Sundstrand Corporation
- Inventors: Steven Poteet; Blair A. Smith; Kevin M. Rankin; William R. Fiske
- Web page: https://patentgrep.com/patent/US20190316629A1

## CPC

- F16C 17/024: {with flexible leaves to create hydrodynamic wedge, e.g. radial foil bearings}
- F16C 17/042: {with flexible leaves to create hydrodynamic wedge, e.g. axial foil bearings}
- F16C 33/1095: {with solids as lubricant, e.g. dry coatings, powder}
- F16C 2206/82: based on tungsten carbide [WC]
- F16C 2223/60: by vapour deposition, e.g. PVD, CVD
- F16C 2360/23: Gas turbine engines
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

An example embodiment of an air bearing assembly includes at least a first member and a shaft with a flange configured to rotate with respect to the first member. The first member has a coating on at least one surface facing at least one of the shaft and the flange. The coating includes tungsten carbide, a nonpolymeric self-lubricating coating, or a combination thereof.

## Claims

### Claim 1

An air bearing assembly, comprising:
a first member; and
a shaft with a flange configured to rotate with respect to the first member;
wherein the first member has a coating on at least one first surface facing at least one second surface of the shaft and the flange, the coating comprising tungsten carbide, a nonpolymeric self-lubricating coating, or a combination thereof.

### Claim 2 (depends on 1)

The air bearing assembly of claim 1, wherein the first member is one of a stationary journal and a stationary foil bearing.

### Claim 3 (depends on 1)

The air bearing assembly of claim 1, wherein the coating can withstand an operating temperature above 550° F. (about 288° C.).

### Claim 4 (depends on 1)

The air bearing assembly of claim 1, wherein the coating can withstand an operating temperature above 750° F. (about 400° C.).

### Claim 5 (depends on 1)

The air bearing assembly of claim 1, wherein the coating is greater than about 0.00004 inch (1 micron) thick.

### Claim 6 (depends on 5)

The air bearing assembly of claim 5, wherein the coating is less than 0.002 inch (50 microns) thick.

### Claim 7 (depends on 1)

The air bearing assembly of claim 1, wherein the coating is free of fluorinated compounds.

### Claim 8 (depends on 1)

The air bearing assembly of claim 1, wherein the self-lubricating coating is selected from a group consisting of: diamond-like carbon (DLC), WS2, WSi2, AgO, Ag, BN, MoS2, and combinations thereof.

### Claim 9 (depends on 1)

The air bearing assembly of claim 1, further comprising:
a second member disposed on a side of the flange opposite the first stationary member, wherein the second member has a coating on a surface facing the flange, the coating comprising tungsten carbide, a nonpolymeric self-lubricating coating, or a combination thereof.

### Claim 10

A foil bearing for an air bearing assembly, the foil bearing comprising:
a plurality of convex foils arranged generally about a rotational axis, the foil bearing having a first side, a second opposing side, and an opening centered therethrough; and
a coating on at least one surface including at least the first side or the second side, the coating comprising tungsten carbide, a nonpolymeric self-lubricating coating, or a combination thereof.

### Claim 11 (depends on 10)

The foil bearing of claim 10, wherein the coating can withstand an operating temperature above 550° F. (about 288° C.).

### Claim 12 (depends on 10)

The foil bearing of claim 10, wherein the coating can withstand an operating temperature above 750° F. (about 400° C.).

### Claim 13 (depends on 10)

The foil bearing of claim 10, wherein the coating is free of fluorinated compounds.

### Claim 14 (depends on 10)

The foil bearing of claim 10, wherein the self-lubricating coating is selected from a group consisting of: diamond-like carbon (DLC), WS2, WSi2, AgO, Ag, BN, MoS2, and combinations thereof.

### Claim 15

A method of making a foil bearing for an air bearing assembly, comprising:
arranging a plurality of convex foils generally about a rotational axis to form a foil bearing, the foil bearing having a first side, a second opposing side, and an opening centered therethrough, about the rotational axis; and
applying a coating comprising tungsten carbide, a nonpolymeric self-lubricating coating, or a combination thereof to at least one of the first face and the second face by one of plasma spraying, chemical vapor deposition, and physical vapor deposition.

### Claim 16 (depends on 15)

The method of claim 15, wherein the self-lubricating coating is selected from a group consisting of: diamond-like carbon (DLC), WS2, WSi2, AgO, Ag, BN, MoS2, and combinations thereof.

### Claim 17 (depends on 15)

The method of claim 15, wherein the coating is greater than about 0.00004 inch (1 micron) thick and less than 0.002 inch (50 microns) thick.

### Claim 18 (depends on 15)

The method of claim 15, wherein the coating is free of fluorinated compounds.