Cage and rolling bearing

摘要

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.

主权项

1. 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.