There is provided an apparatus for manufacturing a thin uneven member. The apparatus includes a lower die fixed to a press bed, an upper die fixed to a ram and disposed opposed to the lower die, and a pressure-drive unit which presses the ram using a servo motor as a power source, the servo motor being fixed to a first support member. The pressure-drive unit includes a motion converting mechanism which converts a rotation of the servo motor to a linear motion of a lifting member, and a cylinder block connected and fixed to the first support member and including first and second pistons arranged in series vertically, wherein the first piston is connected to the lifting member through a second support member, and the second piston, larger in diameter than the first piston, presses the ram.

A plate-shaped workpiece forming method of post-machining a pocket (3) on a curved inner surface of a plate-shaped workpiece (2) in a state where the plate-shaped workpiece (2) curved by a curving machine (10) is spread flat. The method includes a curving step (A) of setting a net curve radius (R.sub.0) obtained by adding a curve radius contraction amount (R.sub.1) due to spring-in to a finished curve radius (R) of a plate-shaped workpiece (2), taking into account an amount of contraction of the curve radius of the plate-shaped workpiece (2) between before and after machining of a pocket (3) due to spring-in, and curving the plate-shaped workpiece (2) so as to achieve the net curve radius (R.sub.0); and a pocket machining step of post-machining the pocket (3) by flatly spreading the curved plate-shaped workpiece (2).

A plate-shaped workpiece forming method of post-machining a pocket (3) on a curved inner surface of a plate-shaped workpiece (2) in a state where the plate-shaped workpiece (2) curved by a curving machine (10) is spread flat. The method includes a curving step (A) of setting a net curve radius (R.sub.0) obtained by adding a curve radius contraction amount (R.sub.1) due to spring-in to a finished curve radius (R) of a plate-shaped workpiece (2), taking into account an amount of contraction of the curve radius of the plate-shaped workpiece (2) between before and after machining of a pocket (3) due to spring-in, and curving the plate-shaped workpiece (2) so as to achieve the net curve radius (R.sub.0); and a pocket machining step of post-machining the pocket (3) by flatly spreading the curved plate-shaped workpiece (2).

A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon from outside to inside, whereby the end of the rectangular tube is radially reduced.

A method of manufacturing a rectangular tube having a stepped portion includes: forming V-shaped grooves on a rectangular tube at surfaces of an end thereof in a direction parallel to a longitudinal direction thereof; and pressing each of the surfaces having the V-shaped grooves formed thereon from outside to inside, whereby the end of the rectangular tube is radially reduced.

Disclosed is a battery cell with improved weldability and an apparatus for processing the same, and more particularly to a battery cell including an electrode assembly received in a cell case; and a pair of electrode leads constituted by a negative electrode lead and a positive electrode lead protruding outwards from the cell case, wherein: the negative electrode lead is made of a nickel material and is provided with one or more embossed portions, and the positive electrode lead is made of an aluminum material and is provided with no embossed portion.

Disclosed is a battery cell with improved weldability and an apparatus for processing the same, and more particularly to a battery cell including an electrode assembly received in a cell case; and a pair of electrode leads constituted by a negative electrode lead and a positive electrode lead protruding outwards from the cell case, wherein: the negative electrode lead is made of a nickel material and is provided with one or more embossed portions, and the positive electrode lead is made of an aluminum material and is provided with no embossed portion.

An inner diameter of a first end of a tubular component, positioned in relation to a first die, is reduced through relative movement between the tubular component and the first die such as to produce a first conical area between first and second ends of the tubular component. The first conical area is then formed through relative movement of a second die to create in a longitudinal section of the first conical area an outer circumferential embossment and an inner bead having an inner diameter smaller than the inner diameter of the first end. The first end is widened through insertion of an inner tool, while the tubular component is supported on an outside in a mold cavity of an outer tool. An inner contour with an internal stop is formed as an outer surface of the first end of the tubular component rests flatly in the mold cavity.

A clutch hub which is engaged with the clutch plates in an outer circumference is a press-molding article made from one steel sheet. In its inner circumferential surface, plural oil grooves for cooling the clutch plates, which are extended to a shaft direction and have a space in a circumferential direction. Each of dams as a press-molding portion extending to radial inward is formed at an end portion of each of the oil groove. The dams include an upright front surface and a back surface, and the bottom surfaces and both side surfaces of the oil grooves are integrated with the dams at the front surface side and the back surface side.

A clutch hub which is engaged with the clutch plates in an outer circumference is a press-molding article made from one steel sheet. In its inner circumferential surface, plural oil grooves for cooling the clutch plates, which are extended to a shaft direction and have a space in a circumferential direction. Each of dams as a press-molding portion extending to radial inward is formed at an end portion of each of the oil groove. The dams include an upright front surface and a back surface, and the bottom surfaces and both side surfaces of the oil grooves are integrated with the dams at the front surface side and the back surface side.