Aida Engineering, Ltd.

Tadahiro Kondo

Yasuyuki Kohno

Ryosho Iwamura

Junji Makabe

Akira Yamanouchi

Kazufumi Tsuchida

Minoru Somukawa

The die cushion device includes a first hydraulic cylinder for supporting a cushion pad, and a first hydraulic circuit for driving the first hydraulic cylinder. The first hydraulic circuit is a hydraulic closed circuit including a logic valve connected between a die cushion pressure generation line and a system pressure line, and a hydraulic pump driven by a first servomotor for applying a pilot pressure to the logic valve. The first controller controls the first servomotor (pilot pressure) based on a first pressure command corresponding to the die cushion force and the pressure detected by the first pressure detector to control the pressure in a lower chamber of the first hydraulic cylinder so that the pressure is equal to a pressure corresponding to the first pressure command.

Die cushion device

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).

There is provided a die cushion device that includes a cushion pad, a hydraulic cylinder configured to lift the cushion pad, and a hydraulic closed circuit connected to a die cushion pressure creation chamber of the hydraulic cylinder. The hydraulic closed circuit includes a pilot drive type logic valve that is operable as a main relief valve at the time of the die cushion operation, and a pilot relief valve configured to create pilot pressure for controlling the logic valve. Hydraulic oil is filled in the hydraulic closed circuit, in a pressurized manner, and the hydraulic oil in the hydraulic closed circuit is pressurized by only die cushion force applied from the cushion pad through the hydraulic cylinder, in one cycle period of the cushion pad.

An apparatus for checking an inclination of a cushion pad includes: a plurality of height position detectors that detect a plurality of respective height positions in a vertical direction at a plurality of positions different in a horizontal direction of the cushion pad; an inclination measurement unit that measures information on an inclination of the cushion pad in accordance with the plurality of height positions detected by the plurality of respective height position detectors; and an input/output unit that outputs the information on an inclination of the cushion pad measured by the inclination measurement unit to a display or a printer in a visible manner.

Apparatus and method for checking inclination of cushion pad

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.

Die cushion apparatus of press machine and die cushion controlling method

There is provided a press machine which can apply a large compression force to a mold as well as impart smooth vibration only in a rectilinear advancing direction to the mold, and thereby can improve the press-formability. A main slide and a sub-slide constitute a slide and at the same time a cylinder-piston mechanism. During press-forming, a compression force is transmitted to the sub-slide (an upper mold) through hydraulic pressure applied interlockingly with driving of the main slide, and the sub-slide is vibrated with the hydraulic pressure being periodically changed. Favorable press-forming can be performed even under relatively difficult press-forming conditions, by controlling the vibration such that a vibration frequency of the sub-slide (the upper mold) becomes 9 Hz or higher but 33.3 Hz or lower and a vibration amplitude of the sub-slide becomes 0.05 mm or larger but 0.5 mm or smaller.

Press machine and method for controlling slide of press machine

The present invention provides a servo press system and a drawing method using the servo press system. The drawing method according to the aspect of the present invention includes: a stopping step of stopping the slide for a first period in a course of a stroke for performing drawing; a keeping step of reducing the die cushion force to below a predetermined die cushion force and keeping the die cushion force for a second period within the first period for which the slide is stopped; and a restarting step of restarting the slide after keeping the die cushion force for the second period, wherein drawing including the stopping step, the keeping step, and the restarting step is performed at least one time in the course of the stroke for performing drawing.

Drawing method and servo press system

A die cushion force control method and a die cushion apparatus generates a die cushion force on a cushion pad based on a die cushion force command value set in advance. A die cushion force command value equal to or larger than a target die cushion force command value is outputted initially in order to suppress an initial die cushion force overshoot generated when the target die cushion force command value configured to be stepwise is used as the die cushion force command value, then a die cushion force command value decreased continuously (gradually) so as to be smaller than the target die cushion force command value is outputted, and subsequently a die cushion force command value increasing gradually so as to be equal to the target die cushion force command value is outputted.

Die cushion force control method and die cushion apparatus

In a mechanical press, the pressure (cylinder force) of a hydraulic pressure chamber of a cylinder-piston mechanism provided in a slide of the mechanical press can be variably controlled with a high responsiveness by a hydraulic pump/motor driven by an electric servomotor, in response to a cylinder force command corresponding to the press load command. Accordingly, even if a die height value is set to a value small enough to cause an overload, the press load can be restricted before the occurrence of the overload, and this can save the trouble of strictly adjusting the die height value. Further, pressure-application time in the vicinity of a bottom dead center can be lengthened, and a breakthrough phenomenon can be suppressed from occurring at the end of pressure application. Still further, because the overload does not occur, pressure oil is not relieved, so that the interruption of a press operation is avoided.

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Sagamihara, Japan

Tadahiro Kondo