Method for manufacturing a ball bearing, notably for a butterfly valve in an aeronautical environment

Patent metadata

Field	Value
Publication number	US-10119569-B2
Application number	US-201314650573-A
Country	US
Kind code	B2
Filing date	Dec 18, 2013
Priority date	Dec 21, 2012
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

The manufacturing method notably includes a step (110) for sintering steel powder (10), the chemical composition of which includes, in mass percent, 2.3% of carbon, 4.2% of chromium, 7% of molybdenum, 6.5% of tungsten, 10.5% of cobalt and 6.5% of vanadium, so as to obtain a sintered steel (12) and shaping of the sintered steel (12), for forming a bearing ring (18).

First claim

The invention claimed is:

1. A method for manufacturing a ball bearing of a butterfly valve for an aeronautical application, comprising:
sintering a steel powder, the chemical composition of which includes in mass percent, 2.3% of carbon, 4.2% of chromium, 7% of molybdenum, 6.5% of tungsten, 10.5% of cobalt and 6.5% of vanadium, so as to obtain a sintered steel;
shaping the sintered steel, to form a bearing ring of the butterfly valve of an aeronautical application, comprising:
rolling the sintered steel, to form a steel bar;
cutting the steel bar, to form a steel washer;
and machining the steel washer, to form the bearing ring, so as to give it an annular general shape having an inner surface and an outer surface;

and assembling the ball bearing, the ball bearing comprising said bearing ring and a plurality of balls.

2. The manufacturing method according to claim 1 , comprising, subsequent to said machining, heat treatment of the bearing ring.

3. The manufacturing method according to claim 2 , comprising, subsequent to said heat treatment, rectification of the inner and outer surfaces of the bearing ring, so as to give it a predetermined shape and predetermined final dimensions.

4. A method for manufacturing a butterfly valve for an aeronautical application, comprising
manufacturing a ball bearing, comprising:
sintering a steel powder, the chemical composition of which includes in mass percent, 2.3%/of carbon, 4.2%/of chromium, 7%/of molybdenum, 6.5%/of tungsten, 10.5%/of cobalt and 6.5%/of vanadium, so as to obtain a sintered steel;
shaping of the sintered steel, for forming a bearing ring of the butterfly valve of an aeronautical application, comprising:
rolling the sintered steel to form a steel bar;
cutting the steel bar to form a steel washer;
and machining the steel washer to form the bearing ring, so as to give it an annular general shape having an inner surface and an outer surface;

and assembling the ball bearing in the butterfly valve, the ball bearing comprising the bearing ring and a plurality of balls.

5. The manufacturing method according to claim 4 , comprising, subsequent to said machining, heat treatment of the bearing ring.

6. The manufacturing method according to claim 5 , comprising, subsequent to said heat treatment, rectification of the inner and outer surfaces of the bearing ring, so as to give it a predetermined shape and predetermined final dimensions.

7. A method for manufacturing a ball bearing of a butterfly valve for an aeronautical application, comprising:
sintering a steel powder, the chemical composition of which includes in mass percent, 2.3% of carbon, 4.2% of chromium, 7% of molybdenum, 6.5% of tungsten, 10.5% of cobalt and 6.5% of vanadium, so as to obtain a sintered steel;
shaping the sintered steel, to form a bearing ring of the butterfly valve of an aeronautical application having satisfactory hardness and corrosion resistance at temperatures on the order of 500 degrees C., comprising:
rolling the sintered steel, to form a steel bar;
cutting the steel bar, to form a steel washer;
machining the steel washer, to form the bearing ring, so as to give it an annular general shape having an inner surface and an outer surface;
and heat treatment of the bearing ring, comprising:
mild annealing for approximately three hours in a protected atmosphere at a temperature between 850 degrees C. and 900 degrees C.;
slow cooling of approximately 10 degrees C. per hour in open air, to a temperature of approximately 700 degrees C.;
detensioning annealing for approximately two hours at a temperature between 600 degrees C. and 700 degrees C.; slow cooling down to a temperature of approximately 500 degrees C.;
quenching in a protected atmosphere with pre-heating in two stages, namely, a first stage at a temperature between 450 degrees C. and 500 degrees C., and a second stage at a temperature between 850 degrees C. and 900 degrees C.;
austenization at a temperature based on a desired hardness; cooling down to a temperature between 40 degrees C. and 50 degrees C.; annealing of at least one hour at a temperature of approximately 560 degrees C.; and cooling down to room temperature;

and assembling the ball bearing, the ball bearing comprising said bearing ring and a plurality of balls.

8. The manufacturing method according to claim 7 , comprising, subsequent to said heat treatment, rectification of the inner and outer surfaces of the bearing ring, so as to give it a predetermined shape and predetermined final dimensions.

Assignees

• Skf Aerospace France
• Liebherr Aerospace Toulouse Sas

Inventors

• Le Jeune Gwénolé
• Maheo Yves
• Rocchi Jérôme

Classifications

• B22F2003/247

  Removing material: carving, cleaning, grinding, hobbing, honing, lapping, polishing, milling, shaving, skiving, turning the surface · CPC title

• F16K1/224

  Details of bearings for the axis of rotation · CPC title

• C22C38/24

  with vanadium · CPC title

• B22F3/10

  Sintering only · CPC title

• C22C38/36

  with more than 1.7% by weight of carbon · CPC title