Wrinkle generation detecting device, die cushion device and die protection device, and wrinkle generation detecting method, die cushion force automatic setting method and die protecting method

A die cushion device comprising:

• a die cushion force generator configured to generate a die cushion force in a cushion pad;
• a die cushion force automatic command unit configured to output a die cushion force command;
• a die cushion force controller configured to control the die cushion force generator such that the die cushion force is generated in the cushion pad based on the die cushion force command;
• and
• a wrinkle generation detection device for a press machine having the die cushion device which supports the cushion pad and generates the die cushion force when a slide of the press machine is lowered, the wrinkle generation detection device comprising:
• a slide position detector configured to detect a height position of the slide;
• a cushion pad position detector configured to detect a height position of the cushion pad;
• and
• a computing unit configured to consecutively calculate a deviation between the height position of the slide detected by the slide position detector and the height position of the cushion pad detected by the cushion pad position detector, during a time period from a start of forming of a material by the slide lowering to an end of the forming,
• wherein a wrinkle generated in the material is detected based on an increase of the deviation consecutively calculated by the computing unit,
• wherein the die cushion force automatic command unit outputs a preset die cushion force command,
• wherein when an increase of the deviation is detected by the wrinkle generation detection device, the die cushion force automatic command unit increases the die cushion force command being presently outputted from a time point when the increase of the deviation is detected,
• wherein when the increase of the deviation is stopped, the die cushion force automatic command unit stops the increase of the die cushion force command from a time point when the increase of the deviation is stopped, and the die cushion force command is automatically reset,
• wherein the slide is driven to obtain a predetermined slide velocity,
• wherein the cushion pad position detector is provided at each of a plurality of spots of the cushion pad and detects each of height positions at the plurality of spots of the cushion pad, and
• wherein the computing unit calculates each of deviations between the height position of the slide detected by the slide position detector and the height positions at each of the plurality of spots of the cushion pad detected by each cushion pad position detector.