Electro-chemical hardening of bearing raceways

Patent metadata

Field	Value
Publication number	US-10480581-B2
Application number	US-201815953025-A
Country	US
Kind code	B2
Filing date	Apr 13, 2018
Priority date	Jun 6, 2017
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A method of making bearings includes treating a metallic surface of a bearing raceway with a pulsed electrochemical processing nozzle to transform the amorphous oxide into a crystalline structure on the metallic surface electro-chemically and convert the metallic surface into a ceramic like hardness surface. Treating the metallic surface can include forming a gradient in material composition transitioning from a purely metallic material at a cross-sectional position within the bearing raceway to a purely crystalline structure material at the ceramic like hardness surface of the bearing raceway.

First claim

What is claimed is:

1. A method of making bearings comprising a bearing raceway rotatably housing a plurality of ceramic rolling elements, the method comprising:
treating a metallic surface of the bearing raceway with a pulsed electrochemical processing nozzle to transform amorphous oxide into a crystalline structure on the metallic surface electro-chemically and convert the metallic surface into a ceramic like hardness crystalline structure surface.

2. The method as recited in claim 1 , wherein treating the metallic surface includes forming a gradient in material composition transitioning from a purely metallic material at a cross-sectional position within the bearing raceway to a purely ceramic like hardness crystalline structure material at the surface of the bearing raceway.

3. The method as recited in claim 2 , wherein a gradient depth is defined from the cross-sectional position where the gradient in material composition is a purely metallic material, to the purely ceramic like hardness crystalline structure surface, wherein the gradient depth is within a range up to 300 microns.

4. The method as recited in claim 1 , wherein treating the metallic surface of the bearing raceway includes treating a radially outward facing metallic surface of an inner raceway, and leaving a radially inward facing metallic surface of the inner raceway metallic.

5. The method as recited in claim 1 , wherein treating the metallic surface of the bearing raceway includes treating a radially inward facing metallic surface of an outer raceway, and leaving a radially outward facing metallic surface of the inner raceway metallic.

6. The method as recited in claim 1 , wherein the bearing raceway is an inner bearing raceway, wherein treating the metallic surface of the bearing raceway includes treating a radially outward facing metallic surface of the inner raceway, and leaving a radially inward facing metallic surface of the inner raceway metallic, and further comprising:
treating a metallic surface of an outer bearing raceway with an electro-chemical processing nozzle to transform amorphous oxide into a crystalline structure on the metallic surface of the outer bearing raceway electro-chemically to convert the metallic surface into a ceramic like hardness crystalline structure surface, wherein treating the metallic surface of the outer bearing raceway includes treating a radially inward facing metallic surface of the outer raceway, and leaving a radially outward facing metallic surface of the inner raceway metallic; and
assembling the inner and outer bearing raceways together with a plurality of ceramic rolling elements therebetween.

7. The method as recited in claim 1 , wherein converting the metallic surface into a ceramic like hardness crystalline structure surface includes hardening the metallic surface into a ceramic like hardness crystalline structure surface with a hardness greater than or equal to a hardness of 80 on the Rockwell hardness scale.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Hansen Bruce D
• Fallon Jr William P

Classifications

• F16C33/303

  of hybrid bearings, e.g. rolling bearings with steel races and ceramic rolling elements · CPC title

• F16C2223/10

  Hardening, e.g. carburizing, carbo-nitriding · CPC title

• F16C2361/65

  Gear shifting, change speed gear, gear box · CPC title

• F16C33/64

  Special methods of manufacture · CPC title

• F16C19/06

  with a single row or balls · CPC title