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US 6,289,710 B1Granted
Method of manufacturing a hollow rack bar
AssigneeTRW Automotive Japan Co., Ltd.
InventorKeita Ozeki
Life of this patent
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Abstract
A method for manufacturing a hollow rack bar having a flat portion thick enough, which prevents difficulty in pulling out a core after press working. The flat portion is formed by inserting the core having an approximately central depression in the longitudinal direction into a steel pipe and pressing the steel pipe from the outside by an upper and a lower dies. Subsequent to the formation of the flat portion, rack teeth are formed by placing the steel pipe in a tooth profile forming die and forcibly inserting a mandrel into the steel pipe.
Claims3
A method of manufacturing a hollow rack bar comprising the steps of:
- providing a hollow steel pipe;
- inserting a core having a surface defining a central depression in the longitudinal direction into said steel pipe;
- pressing said steel pipe from the outside using metal dies to form a flat portion on said steel pipe and a gap between said surface defining a central depression and said flat portion;
- removing said core from said steel pipe;
- and
- forming rack teeth on said flat portion.
3 more elements
Dependencies are inferred from the claim text.