Method of manufacturing steering shaft
AssigneeHitachi Astemo, Ltd.
InventorsTakateru SEKI, Norihiro KIMURA, Takeo OKABE
Life of this patent
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Abstract
A method of manufacturing a rack bar includes: a rolling die abutment step of bringing a pair of rolling dies into abutment against an intermediate portion of a workpiece; and a ball screw groove forming step of forming a ball screw groove in the workpiece by moving the workpiece relative to the pair of rolling dies so that a region of the workpiece against which the pair of rolling dies is brought into abutment is moved from the intermediate portion toward a first end portion of the workpiece.
Claims8
A method of manufacturing a steering shaft of a steering device, the steering shaft having a bar shape, and including a first end portion, a second end portion, and an intermediate portion formed between the first end portion and the second end portion,
- the method comprising:
- a rolling die abutment step of bringing a rolling die into abutment against a workpiece being a material for forming the steering shaft;
- and
- a ball screw groove forming step of forming a ball screw groove in the workpiece in a first state,
- wherein in the rolling die abutment step, the rolling die is brought into abutment against the intermediate portion of the workpiece in the first state, and
- wherein in the ball screw groove forming step, the workpiece is moved relative to the rolling die so that a region of the workpiece against which the rolling die is brought into abutment is moved from the intermediate portion toward the first end portion, thereby forming the ball screw groove in the workpiece and forming the workpiece in a second state.
A method of manufacturing a steering shaft of a steering device, the steering shaft having a bar shape, and including a first end portion, a second end portion, and an intermediate portion formed between the first end portion and the second end portion,
- the method comprising:
- a rolling die abutment step of bringing a rolling die into abutment against a workpiece being a material for forming the steering shaft;
- and
- a ball screw groove forming step of forming a ball screw groove in the workpiece in a first state,
- wherein in the rolling die abutment step, in a longitudinal direction of the steering shaft of the rolling die, entire regions of the parallel portions, which are portions other than a lead portion and a relief portion, are brought into abutment against the workpiece in the first state, and
- wherein in the ball screw groove forming step, the workpiece is moved relative to the rolling die so that a region of the workpiece against which the rolling die is brought into abutment is moved along the longitudinal direction of the steering shaft, thereby forming the ball screw groove in the workpiece and forming the workpiece in a second state.
Dependencies are inferred from the claim text.