Method for manufacturing motor vehicle door hinge
AssigneesHiroshi Ogawa, Kazuya Ogawa
InventorsHiroshi Ogawa, Kazuya Ogawa, Michihiro Yokoyama
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Abstract
A method for manufacturing a high-strength motor vehicle door hinge from a steel plate blank includes a cold heading step of forming a cylindrical bulging portion at one end of the blank in the width direction, a shaft hole forming step of forming a shaft hole in the cylindrical bulging portion, and a shaft hole finishing step. In the shaft hole forming step, a shaft hole is formed using a first punch having a top end with a shape of a cone and a first die having an inner wall with a gap volume relative to the outer circumferential surface of the cylindrical bulging portion of the blank.
Claims11
A method for manufacturing a motor vehicle door hinge from a steel plate blank having predetermined thickness, width, and height using processes including cold heading and punching, the method comprising:
- a cold heading step of forming, at one end of the blank in the width direction, a cylindrical bulging portion having a bulged cylindrical shape bulging in the thickness direction so as to have a horizontal cross section of a circular shape or an elliptical shape and extending in the height direction by cold heading;
- a shaft hole forming step of forming a shaft hole that passes through the cylindrical bulging portion along the shaft axis using a first punch and a first die, the shaft hole allowing a hinge pin to pass therethrough;
- and
- a shaft hole finishing step of punching the shaft hole formed in the shaft hole forming step from the end at which machining of the first punch ends using a second punch and a second die;
- wherein a height of the cylindrical bulging portion of the shaft hole formed in the shaft hole forming step is twice or more a diameter of the shaft hole, and
- wherein the first punch used in the shaft hole forming step has a top end having a shape of a cone with a cone angle in the range from 70° to 120°, and
- wherein the first die has an inner wall having a gap relative to an outer circumferential surface of the cylindrical bulging portion of the blank, and the size of a gap volume formed by the outer circumferential surface of the cylindrical bulging portion and the inner wall is set so that when the first punch punches the cylindrical bulging portion of the blank, a hole portion formed from the end at which machining of the first punch starts to a predetermined length position does not produce a punched slug and the cylindrical bulging portion bulges outward and a hole portion from the predetermined length position to the end at which the machining of the first punch ends produces a punched slug to be ejected, and
- wherein the second die has a shape substantially the same as the shape of the first die, and
- wherein the second punch has a top end having a shape of a truncated cone or a cone with a cone angle in the range from 70° to 120° and a largest diameter that is larger than that of the first punch by 0.1 mm to 0.3 mm.
A method for manufacturing a motor vehicle door hinge from a steel plate blank having predetermined thickness, width, and height using processes including cold heading and punching, the method comprising:
- a cold heading step of forming, at one end of the blank in the width direction, a protrusion attached cylindrical bulging portion having a protrusion attached cylindrical bulging shape that bulges in the thickness direction so as to have a horizontal cross section of a circular shape or an elliptical shape and that extends in the height direction and having a protrusion on the top end of the circular shape or the elliptical shape by cold heading, the protrusion serving as a door stopper;
- a shaft hole forming step of forming a shaft hole that passes through the protrusion attached cylindrical bulging portion along the shaft axis using a first punch and a first die, the shaft hole allowing a hinge pin to pass therethrough;
- and
- a shaft hole finishing step of punching the shaft hole formed in the shaft hole forming step from the end at which machining of the first punch ends using a second punch and a second die;
- wherein the first punch used in the shaft hole forming step has a top end having a shape of a cone with a cone angle in the range from 70° to 120°, and
- wherein a height of the protrusion attached cylindrical bulging portion of the shaft hole formed in the shaft hole forming step is twice or more a diameter of the shaft hole, and
- wherein the first die has an inner wall having a gap relative to an outer circumferential surface of the protrusion attached cylindrical bulging portion of the blank, and wherein the size of a gap volume formed by the outer circumferential surface of the protrusion attached cylindrical bulging portion and the inner wall is set so that when the first punch punches the protrusion attached cylindrical bulging portion of the blank, a hole portion formed from an end at which machining of the first punch starts to a predetermined length position does not produce a punched slug and the protrusion attached cylindrical bulging portion bulges outward and a hole portion from the predetermined length position to the end at which the machining of the first punch ends produces a punched slug to be ejected, and
- wherein the second die has a shape substantially the same as the shape of the first die, and
- wherein the second punch has a top end having a shape of a truncated cone or a cone with a cone angle in the range from 70° to 120° and a largest diameter that is larger than that of the first punch by 0.1 mm to 0.3 mm.
Dependencies are inferred from the claim text.