US4687556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preventing stress corrosion cracking of bearings
Assignee: Boeing North American Inc
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Filing: 1985-12-19
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Granted: 1987-08-18
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Expires: 2005-12-19
Abstract
Abstract A method of inhibiting stress corrosion cracking of a bearing 10 of the type installed on a shaft with an interference fit. The surface of the inner ring 16 is shot peened at least at and near the junctures 28,30 of the endwalls 22,24 with cylindrical inner surface 26. The shot peening is performed with sufficient intensity to produce residual compressive stress which offsets at least a portion of the tensile stress resulting from the installation interference fit. The shot peened surface is then coated with a thin metallic material. Finally, the inner bearing ring 16 is baked to remove hydrogen resulting from the coating.
Inventors
- 👤 Robert F. Sutton
- 👤 Kathleen E. Kirkham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:10
CPC Classifications
F; F16; F16C; F16C33/00; F16C33/30; C; C25; C25D; C25D5/00; C25D5/34; C25D5/36; F16C35/00; F16C35/04; F16C35/06; F16C35/063
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
123 words
A method of inhibiting stress corrosion cracking of a bearing of the type installed on a shaft with an interference fit said bearing including an inner ring having a substantially cylindrical inner surface terminating at opposite ends and having radially extending endwalls, comprising the sequential steps of: (a) shot peening the surface of the inner ring at least at and near the junctures of the endwalls with said cylindrical inner surface, said shot peening being performed with sufficient intensity to produce residual compressive stress which offsets at least a portion of the tensile stress resulting from installation interference fit; (b) coating the shot peened surface with a thin metallic material; and (c) baking the inner ring to remove hydrogen resulting from said coating.
Claim 2
Independent Claim
123 words
A method of inhibiting stress corrosion cracking of a bearing of the type installed on a shaft with an interference fit said bearing including an inner ring having a substantially cylindrical inner surface terminating at opposite ends and having radially extending endwalls, comprising the sequential steps of: (a) shot peening the surface of the inner ring at least at and near the junctures of the endwalls with said cylindrical inner surface, said shot peening being performed with sufficient intensity to produce residual compressive stress which offsets at least a portion of the tensile stress resulting from installation interference fit; (b) coating the shot peened surface with a thin metallic material; and (c) baking the inner ring to remove hydrogen resulting from said coating.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein the shot peening is performed at an Almen intensity within the range of 0.009N to 0.014 A.
Claim 4
Dependent Claim
25 words
The method of claim 2 wherein the residual compressive stress produced extends to a depth of 0.002 to 0.007 inches below the shot peened surface.
Claim 5
Dependent Claim
24 words
The method of claim 1 wherein said coating step has the effect of producing a metallic material with a minimum thickness of 0.0002 inches.
Claim 6
Dependent Claim
12 words
The method of claim 4 wherein the metallic material is electrodeposited nickel.
Claim 7
Dependent Claim
17 words
The method of claim 1 wherein the inner ring is formed of a hardened martensitic stainless steel.
Claim 8
Dependent Claim
17 words
The method of claim 6 wherein the inner ring is formed of AISI type 440C stainless steel.
Claim 9
Dependent Claim
33 words
The method of claim 1 wherein the shot peening medium is steel shot with a hardness in excess of R c 60 and wherein any residual steel shot remaining is removed by passivation.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein the shot peening medium is glass beads.
Claim 11
Dependent Claim
13 words
The method of claim 1 wherein the shot peening medium is ceramic beads.
Claim 12
Dependent Claim
24 words
The method of claim 1 wherein the inner ring is baked at between 250° F. and 300° F. for between six and ten hours.
Claim 13
Dependent Claim
16 words
The method of claim 1 wherein the shot peened surface includes the entirety of said endwalls.
Claim 14
Dependent Claim
17 words
The method of claim 1 wherein the shot peened surface includes the entirety of said inner surface.
Claim 15
Dependent Claim
20 words
The method of claim 1 wherein the shot peened surface includes the entirety of said endwalls and said inner surface.
References Cited (Backward Citations)
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Cited
US3642519A
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US3754976A
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US3844846A
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US4034585A
Cited
US4470184A
Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-17 | 1991-02-16 | 1991-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-17 | 1995-02-16 | 1995-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-17 | 1999-02-16 | 1999-08-18 | $7700.00 | Window Closed / Lapsed |