Forging die, and method and apparatus for controlling the same

A control apparatus for a forging die for forging a forging material by relatively displacing a first die member and a second die member to apply a pressurizing force of a punch member to said forging material charged in a cavity, said punch member being movably disposed with respect to one of said first die member and said second die member under action of a pressure fluid, said control apparatus comprising

• a buffering mechanism for absorbing a residual placement amount of said punch member before arrival of said punch member at a bottom dead center position within said cavity after abutment between said first die member and said second die member, and then permitting further movement of said punch member to said bottom dead center position in said cavity in accordance with an action of said pressure fluid charged in a pressure chamber as a result said relative displacement of said first die member and said second die member;
• a pressure-detecting mechanism for detecting a pressure of said pressure fluid charged in said pressure chamber;
• and
• a pressure fluid control mechanism comprising a relief valve having a relief chamber chargeable with said pressure fluid for discharging said pressure fluid from said pressure chamber to the outside through said relief valve if it is judged that said forging material is not charged in said cavity when said pressure of said pressure fluid charged in said pressure chamber does not arrive at an initial preset pressure at an initial stage of forging, on the basis of a detection signal outputted from said pressure-detecting mechanism.

A method for controlling a forging die for forging a forging material by relatively displacing a first member and a second die member to apply a pressurizing force of a punch member to said forging material charged in a cavity, said punch member being movably disposed with respect to one of said first die member and said second die member under action of a pressure fluid charged in a pressure chamber, said method comprising the steps of:

• supplying said pressure fluid to said pressure chamber to a relief chamber of a relief valve;
• allowing said first die member and said second die member to make abutment before arrival of said punch member at a bottom dead center position within said cavity as a result of relative displacement of said first die member and said second member;
• allowing further movement of said punch member to said bottom dead center position in said cavity;
• absorbing a residual displacement amount of said punch member before arrival of said punch member at said bottom dead center position within said cavity after said abutment between said first die member and said second die member;
• and
• forcibly discharging said pressure fluid from said pressure chamber to the outside through said relief valve when a forming load is applied to said pressure fluid charged in said pressure chamber and a pressure of said pressure fluid arrives at a relief preset pressure.

A method for controlling a forging die provided with buffering mechanism for absorbing a residual displacement amount before arrival of a punch member at a bottom dead center position within a forging cavity after abutment between a first die member and a second die member, said punch member being movably disposed with respect to one of said first die member and said second die member under action of a pressure fluid said method comprising the steps of:

• supplying said pressure fluid to a pressure chamber of said buffering mechanism and to a relief chamber of a relief valve;
• detecting whether or not a pressure of a pressure fluid charged in said pressure chamber of said buffering mechanism arrives at an initial preset pressure at an initial forging stage before said first die member and said second die member make said abutment as a result of relative placement of said first die member and said second member, wherein if said pressure of said pressure fluid does not arrive at said initial preset pressure, then it is judged that no forging material is charged, in said cavity;
• and
• forcibly discharging said pressure fluid charged in said pressure chamber to the outside through said relief valve if said pressure of said pressure fluid does not arrive at said initial present pressure.