A method for press forming an automotive outer panel includes: providing an elastic body to a punch such that the elastic body abuts against a metal sheet away from a portion corresponding to a character line in the metal sheet; abutting a contact surface portion of the protruding elastic body against the metal sheet; and forming the character line with the ridgeline and the valley line by relatively moving the die toward the punch while abutting the contact surface portion against the metal sheet to deform the elastic body such that the elastic body becomes flush with the punch-side forming surface portion at a bottom dead center of forming. A protrusion amount of the elastic body from the punch-side forming surface portion is set such that the elastic body contacts the metal sheet before the ridgeline contacts the metal sheet to cause the metal sheet to become plastically deformed.

A press bolster adaptor for accommodating different die binders with the same press bolster and fixed pin pattern is provided. The bolster adaptor comprises a base plate, a top plate, and a float plate surrounded by side walls of the base plate. A plurality of lower cushion pins are disposed on the press bolster and move the float plate toward the die binder. A plurality of upper cushion pins are disposed on the float plate and extend through pin holes of the top plate for engaging the die binder in the appropriate locations when the float plate is driven by the lower cushion pins. The upper cushion pins can be rearranged in the pin holes to accommodate new die binders having different designs. Alternatively, the top plate can be replaced with a top plate having a different pin pattern to accommodate a different die binder.

A press bolster adaptor for accommodating different die binders with the same press bolster and fixed pin pattern is provided. The bolster adaptor comprises a base plate, a top plate, and a float plate surrounded by side walls of the base plate. A plurality of lower cushion pins are disposed on the press bolster and move the float plate toward the die binder. A plurality of upper cushion pins are disposed on the float plate and extend through pin holes of the top plate for engaging the die binder in the appropriate locations when the float plate is driven by the lower cushion pins. The upper cushion pins can be rearranged in the pin holes to accommodate new die binders having different designs. Alternatively, the top plate can be replaced with a top plate having a different pin pattern to accommodate a different die binder.

To provide a die cushion device which is inexpensive, functional, and capable of locking completely (at or below the slide bottom dead center). The die cushion device includes a cushion pad, a hydraulic cylinder that moves the cushion pad up and down, and a hydraulic closed circuit connected to a die cushion pressure generation chamber of the hydraulic cylinder. The hydraulic closed circuit includes a cushion pad lowering pressure generation line and a second system pressure line in addition to a die cushion pressure generation line and a first system pressure line. When the cushion pad is locked at the bottom dead center, the cushion pad lowering pressure generation chamber is connected to the first system pressure line, and the die cushion pressure generation chamber is connected to the second system pressure line such that the cushion pad is held at or below the slide bottom dead center.

To provide a die cushion device which is inexpensive, functional, and capable of locking completely (at or below the slide bottom dead center). The die cushion device includes a cushion pad, a hydraulic cylinder that moves the cushion pad up and down, and a hydraulic closed circuit connected to a die cushion pressure generation chamber of the hydraulic cylinder. The hydraulic closed circuit includes a cushion pad lowering pressure generation line and a second system pressure line in addition to a die cushion pressure generation line and a first system pressure line. When the cushion pad is locked at the bottom dead center, the cushion pad lowering pressure generation chamber is connected to the first system pressure line, and the die cushion pressure generation chamber is connected to the second system pressure line such that the cushion pad is held at or below the slide bottom dead center.

A member has a wave inhibitor adapted to control the effects of a wave of longitudinally displaced material positioned ahead of an expansion mandrel used to expand the member. The wave inhibitor has a decreasing transverse cross-sectional area to diminish the effects attributable to the wave, such as workpiece distortions, material upset of the workpiece, lengthening of the member, and excessively high strains in the workpiece. The wave inhibitor can also induce radially compressive stresses in the workpiece and produce an interference fit.

A member has a wave inhibitor adapted to control the effects of a wave of longitudinally displaced material positioned ahead of an expansion mandrel used to expand the member. The wave inhibitor has a decreasing transverse cross-sectional area to diminish the effects attributable to the wave, such as workpiece distortions, material upset of the workpiece, lengthening of the member, and excessively high strains in the workpiece. The wave inhibitor can also induce radially compressive stresses in the workpiece and produce an interference fit.

A fixed die and a punch, which moves toward and away from the die, are provided. A series of bulges is formed in sheet metal between depressions and projections of the die and projections and depressions of the punch. In forming, the punch moves toward the die such that the sheet metal is pressed between first convex sections and second and third convex sections of the die and the punch, and subsequently the sheet metal is pressed between fourth convex sections.

A fixed die and a punch, which moves toward and away from the die, are provided. A series of bulges is formed in sheet metal between depressions and projections of the die and projections and depressions of the punch. In forming, the punch moves toward the die such that the sheet metal is pressed between first convex sections and second and third convex sections of the die and the punch, and subsequently the sheet metal is pressed between fourth convex sections.

A sliding frictional force generation mechanism includes a metal hole member having a hole, a metal shaft member fitted in the hole of the hole member in an axially slidable manner, and a lubrication mechanism configured to supply lubricating oil serving as a cooling medium between the holed ember and the shaft member. The shaft member is fitted in the hole in an interference fit state.