Manufacturing apparatus and manufacturing method for stretch-formed product
View Patent ↗There is provided a manufacturing apparatus and a manufacturing method for a stretch-formed product which can improve the yield of material in the stretch forming performed while clamping the blank by the lock beads. The manufacturing apparatus for a stretch-formed product includes a die and a blank holder which have clamping surfaces facing each other, a punch that, in a state where a margin of a blank of a sheet material is clamped by the clamping surfaces of the die and the blank holder, relatively presses a forming region of the blank into the die and thereby performs stretch forming on the forming region of the blank, and lock beads that are provided on the clamping surfaces of the die and the blank holder in mutually similar shapes and have first surfaces, second surfaces that intersect with the first surfaces, and third surfaces that intersect with the second surfaces from outer edges toward the centers of the die and the blank holder, the first surfaces each having a plurality of depression-protrusion parts.
1. A manufacturing apparatus for a stretch-formed product, the manufacturing apparatus comprising:
a die and a blank holder which have clamping surfaces facing each other;
a punch that, in a state where a margin of a blank of a sheet material is clamped by the clamping surfaces of the die and the blank holder, relatively presses a forming region of the blank into the die and thereby performs stretch forming on the forming region of the blank; and
lock beads that are provided on the clamping surfaces of the die and the blank holder in mutually similar shapes and have first surfaces, second surfaces that intersect with the first surfaces, and third surfaces that intersect with the second surfaces from outer edges toward centers of the die and the blank holder, the first surfaces each having a plurality of depression-protrusion parts, wherein
the plurality of depression-protrusion parts each have a fourth surface and a sixth surface facing each other and a fifth surface that intersects with the fourth surface and the sixth surface,
the fourth surface, the fifth surface and the sixth surface intersect with the second surface, and
when the plurality of depression-protrusion parts are viewed from the outer edge toward the center of the blank holder, the plurality of depression-protrusion parts have a trapezoidal shape, a rectangular shape or a combined shape thereof.
2. The manufacturing apparatus for a stretch-formed product according to claim 1 , wherein
in a case where the plurality of depression-protrusion parts each have the trapezoidal shape or the rectangular shape, a pitch interval of the plurality of depression-protrusion parts when a set of a protruded shape and a depressed shape is defined as one pitch is within a range of 5 to 50 mm and a height of the depression-protrusion part is within a range of 1.0 to 10.0 mm.
3. A manufacturing method for a stretch-formed product, the manufacturing method comprising the steps of:
placing a blank of a sheet material between a die and a blank holder which include, on clamping surfaces facing each other, lock beads that have first surfaces, second surfaces that intersect with the first surfaces and third surfaces that intersect with the second surfaces from outer edges toward centers, the first surfaces each having a plurality of depression-protrusion parts, and the lock beads being provided in mutually similar shapes;
clamping a margin of the blank by the die and the blank holder; and
stretch-forming the blank by relatively pressing a forming region of the blank into the die by a punch in a state of clamping the margin of the blank, wherein
the plurality of depression-protrusion parts each have a fourth surface and a sixth surface facing each other and a fifth surface that intersects with the fourth surface and the sixth surface,
the fourth surface, the fifth surface and the sixth surface intersect with the second surface, and
when the plurality of depression-protrusion parts are viewed from the outer edge toward the center of the blank holder, the plurality of depression-protrusion parts have a trapezoidal shape, a rectangular shape or a combined shape thereof.