According to the die cushion apparatus of a press machine and the die cushion controlling method of the present invention, in holding the cushion pad on standby at a desired standby position, it is possible to hold the cushion pad on standby in parallel with the lower faces of the dies mounted to the slide, and if the lower faces of the dies are inclined, it is possible to hold the cushion pad on standby in the state of being inclined. Through this configuration, it is possible to easily allow the material to come into contact with the lower faces of the dies from the beginning of the die cushion force control (beginning of the collision), and also possible to smoothen the die cushion action in the plane, thereby enhancing the formability.

According to the die cushion apparatus of a press machine and the die cushion controlling method of the present invention, in holding the cushion pad on standby at a desired standby position, it is possible to hold the cushion pad on standby in parallel with the lower faces of the dies mounted to the slide, and if the lower faces of the dies are inclined, it is possible to hold the cushion pad on standby in the state of being inclined. Through this configuration, it is possible to easily allow the material to come into contact with the lower faces of the dies from the beginning of the die cushion force control (beginning of the collision), and also possible to smoothen the die cushion action in the plane, thereby enhancing the formability.

Provided is a press apparatus which ensures high production efficiency and has less chances of breakdown. Specifically, the press apparatus has a base placed on a floor, and a platform arranged over the base to face the base and move up and down. A lower die, on which a steel plate is to be placed, is fixed to the base. An upper die is fixed to the platform to press the plate against the lower die and turn it into an initially formed product through a downward movement of the platform, and to pressure-hold the initially formed product with the lower die. A machining die is supported on the platform to move up and down to machine the initially formed product and form a final product by moving down while pressure-holding the initially formed product.

Provided is a press apparatus which ensures high production efficiency and has less chances of breakdown. Specifically, the press apparatus has a base placed on a floor, and a platform arranged over the base to face the base and move up and down. A lower die, on which a steel plate is to be placed, is fixed to the base. An upper die is fixed to the platform to press the plate against the lower die and turn it into an initially formed product through a downward movement of the platform, and to pressure-hold the initially formed product with the lower die. A machining die is supported on the platform to move up and down to machine the initially formed product and form a final product by moving down while pressure-holding the initially formed product.

A cushion pin device for a press having a cushion pad in which a blank holder is seated on the top thereof outside a lower mold, and locks a blank holder to an upper mold while pressurizing an edge of a molded panel, includes: a cushion support disposed below the cushion pad, a cushion cylinder connected with a lower part of the cushion pad to move up or down the cushion pad from the cushion support, a linear scale mounted between the cushion pad and the cushion support to measure the position of the cushion pad, a main pressure control unit that keeps internal pressure of each cushion cylinder similarly, and a sub pressure control unit that is interconnected with the main pressure control unit so as to control the locking position of the cushion pad when each cushion cylinder operates.

A cushion pin device for a press having a cushion pad in which a blank holder is seated on the top thereof outside a lower mold, and locks a blank holder to an upper mold while pressurizing an edge of a molded panel, includes: a cushion support disposed below the cushion pad, a cushion cylinder connected with a lower part of the cushion pad to move up or down the cushion pad from the cushion support, a linear scale mounted between the cushion pad and the cushion support to measure the position of the cushion pad, a main pressure control unit that keeps internal pressure of each cushion cylinder similarly, and a sub pressure control unit that is interconnected with the main pressure control unit so as to control the locking position of the cushion pad when each cushion cylinder operates.

An actuator assembly for a redraw sleeve that operates independently of the ram drive mechanism is provided. The actuator assembly utilizes a servomotor. The servomotor is structured to provide its output shaft with a variable rotation speed so as to accommodate the need for the redraw sleeve to be in selected locations at specific times.

The die cushion device according to the present invention includes a first hydraulic cylinder and a second hydraulic cylinder that are independently and simultaneously controlled. When a cushion pad is pre-pressurized, pressure control is performed on the first hydraulic cylinder via a first hydraulic circuit so that a pressure in a lower chamber of the first hydraulic cylinder is pre-pressurized to a preset pressure, and position control is simultaneously performed on the second hydraulic cylinder via a second hydraulic circuit so that the cushion pad is held in the die cushion standby position. A force with which the first hydraulic cylinder moves the cushion pad upward is balanced with a force with which the second hydraulic cylinder moves the cushion pad downward (a force for holding the die cushion standby position).

The die cushion device according to the present invention includes a first hydraulic cylinder and a second hydraulic cylinder that are independently and simultaneously controlled. When a cushion pad is pre-pressurized, pressure control is performed on the first hydraulic cylinder via a first hydraulic circuit so that a pressure in a lower chamber of the first hydraulic cylinder is pre-pressurized to a preset pressure, and position control is simultaneously performed on the second hydraulic cylinder via a second hydraulic circuit so that the cushion pad is held in the die cushion standby position. A force with which the first hydraulic cylinder moves the cushion pad upward is balanced with a force with which the second hydraulic cylinder moves the cushion pad downward (a force for holding the die cushion standby position).

A die cushion-cum-slide cushion device selectively opens and closes a flow channel between a hydraulic pump/motor driven by a servo motor, and hydraulic cylinders that generate slide cushion force, or a flow channel between the hydraulic pump/motor, and hydraulic cylinders that generate die cushion force, by switching a selector valve. Before applying the slide cushion force is started, the servo motor is controlled to allow the hydraulic cylinders to generate required slide cushion force through a check valve. While the slide cushion force is applied, hydraulic circuits, each of which includes a logic valve, control pressure of the hydraulic cylinders, and hydraulic circuits, each of which includes the servo motor, control die cushion pressure of the hydraulic cylinders.