Roller bearing
AssigneeNsk Ltd.
InventorsYuuji Shimomura, Shinichi Natsumeda
Life of this patent
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Abstract
When a crowning is subjected to a roller or on a rolling surface using a combination of two arcs, a crowning profile is specified in such a manner that each crowning quantity at two points where distances x in a bus extending direction from the center line of the roller are respectively situated at positions of 0.425 and 0.5 times an effective contact length Le, are respectively present between the value of a well-known logarithmic crowning when a bearing load P is 0.4 times a basic load rating C and the value of the logarithmic crowning when the bearing load P is 0.6 times the basic load rating C.
Claims17
A roller bearing comprising:
- a first race having a first raceway;
- a second race having a second raceway;
- and
- a rolling element provided rotatably between the first raceway and the second raceway,
- wherein the sum δ of a crowning quantity of said rolling element and at least a crowning quantity of a first raceway surface of the first raceway, at a first point X1 and a second point X2, wherein said first point X1 is positioned apart from a center of said rolling element or the first raceway in a bus extending direction of a bus of said rolling element by 0.425 Le, and said second point X2 is positioned apart from the center in the bus extending direction by 0.5 Le, where Le denotes an effective contact length in the bus extending direction between the first raceway surface of said first raceway and the rolling surface of the rolling element, satisfies follow equations (1) and (2):
- at the first point X1 - 3.264 C π · L e · E ′ · Z · cos α In ( 0.2775 + 1.583 × R · C π · E ′ · L e 3 · Z · cos α ) ≤ δ ≤ - 4.896 C π · L e · E ′ · Z · cos α In ( 0.2775 + 1.939 × R · C π · E ′ · L e 3 · Z · cos α ) ( 1 )
- and, at the second point X2 - 3.264 C π · L e · E ′ · Z · cos α In ( 2.192 × R · C π · E ′ · L e 3 · Z · cos α ) ≤ δ ≤ - 4.896 C π · L e · E ′ · Z · cos α In ( 2.684 × R · C π · E ′ · L e 3 · Z · cos α ) ( 2 )
- where,
- E′:
- equivalent modulus of elasticity;
- 2/E′=(1−ν12)/E1+(1−ν12)/E2
- E1, E2:
- Young's modulus of the rolling element and the first race,
- ν1, ν2:
- Poisson's ratios of the rolling element and the first race;
- R:
- equivalent radius
- R=r1·r2/(r1+r2)
- r1:
- average of radius of the rolling element or average radius of the rolling element
- r2:
- radius of the first raceway at a center point with a center of the rolling element;
- C:
- basic load rating;
- Z:
- number of rolling elements;
- α:
- contact angle between the first race and the rolling element.
Dependencies are inferred from the claim text.