Cage and rolling bearing
AssigneeNtn Corporation
InventorsMitsuo Kawamura, Eiichiro Shimazu, Yasutake Hayakawa, Takahiro Okuno, Junichi Ooshimo, Ryuichi Sakamoto
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Abstract
A cage is made of a magnesium alloy such as AZ91D, and is molded by means of injection molding. In this cage, a confluence region is brought away to outside the cage during the injection molding. The confluence region is a region including a void formed by merging of flows of the magnesium alloy. When observing a cross sectional surface of the cage, a ratio of an α phase having a grain size of 20 μm or greater is less than 15% in the magnesium alloy constituting the cage.
Claims19
A cage holding a rolling element in a rolling bearing, comprising:
- the cage being made of a magnesium alloy,
- the cage being molded by injection molding,
- the cage not having a confluence region including a void formed by merging of flows of said magnesium alloy in a completely molten state,
- wherein in a cross sectional surface of the cage, an area ratio of an α phase having a grain size of 20 μm or greater being less than 15% in said magnesium alloy,
- wherein a ratio of tensile strength in a weld portion of the cage to tensile strength in a portion other than said weld portion is 0.8 or greater, said weld portion being formed at a region at which the flows of said magnesium alloy are merged during said injection molding.
A cage holding a rolling element in a rolling bearing, comprising:
- the cage being made of a magnesium alloy,
- the cage being molded by injection molding,
- the cage not having a confluence region including a void formed by merging of flows of said magnesium alloy including a liquid phase,
- wherein in a cross sectional surface of the cage, an area ratio of an α phase having a grain size of 20 μm or greater being less than 15% in said magnesium alloy, and
- wherein the cage has a surface provided with an anodized layer having a thickness of 15 μm or smaller.
Dependencies are inferred from the claim text.