A load detection device includes a detector, a wireless transmitter, a power source, and a controller. The load detection device is provided in dies that includes a first die and a second die. The load detection device is installed on at least one of the first die and the second die and configured to detect whether the first die and the second die are in a closed state. The controller is configured to execute an electricity cutoff process of stopping electricity supply from the power source to the detector and the wireless transmitter when the closed state of the first die and the second die has continued for a predetermined time.

A load detection device includes a detector, a wireless transmitter, a power source, and a controller. The load detection device is provided in dies that includes a first die and a second die. The load detection device is installed on at least one of the first die and the second die and configured to detect whether the first die and the second die are in a closed state. The controller is configured to execute an electricity cutoff process of stopping electricity supply from the power source to the detector and the wireless transmitter when the closed state of the first die and the second die has continued for a predetermined time.

To reduce warping of vertical wall portions without causing buckling occurring in a component shape not having a flange portion. A punch and a pad sandwiching a top sheet portion therebetween in the sheet thickness direction, bending blades for bend-forming the vertical wall portions, and stoppers facing the bending blades in the press direction and constraining end portions of a material to be machined are provided. The punch is supported by a first cushion component elastically expandable and contractible in the press direction. The bending blades each have an upper die component and a lower die component disposed facing each other in the press direction with an interval (D) equal to or larger than a set compression amount and a second cushion component interposed between the upper die component and the lower die component, maintaining the interval (D), and contractible in the press direction at a predetermined pressure or more. The cushion pressure of the second cushion component is lower than the cushion pressure of the first cushion component and has such cushion pressure that the second cushion component does not contract during the bend-forming of the vertical wall portions.

To reduce warping of vertical wall portions without causing buckling occurring in a component shape not having a flange portion. A punch and a pad sandwiching a top sheet portion therebetween in the sheet thickness direction, bending blades for bend-forming the vertical wall portions, and stoppers facing the bending blades in the press direction and constraining end portions of a material to be machined are provided. The punch is supported by a first cushion component elastically expandable and contractible in the press direction. The bending blades each have an upper die component and a lower die component disposed facing each other in the press direction with an interval (D) equal to or larger than a set compression amount and a second cushion component interposed between the upper die component and the lower die component, maintaining the interval (D), and contractible in the press direction at a predetermined pressure or more. The cushion pressure of the second cushion component is lower than the cushion pressure of the first cushion component and has such cushion pressure that the second cushion component does not contract during the bend-forming of the vertical wall portions.

Provided is a cushion pin which applies sufficient supporting force to a blank holder of a press molding apparatus even if the number of cushion pins and an arrangement region are restricted. A cushion pin (1A) has a cylindrical main body section including a plurality of cylindrical members (2) and annular members (3). The cylindrical members (2) are arranged in series in an axial direction, and the annular members (3) are disposed between the adjacent cylindrical members (2). A rod member (4) and a coil spring (5) are disposed in each the spring chambers of the main body section. The rod member (4) includes a rod-shaped part (4b) and a flange part (4a). The rod-shaped part (4b) has a diameter allowing the rod-shaped part (4b) to slidably penetrate through an opening (3a) of the annular member (3). The coil spring (5) biases the flange part (4a).

Provided is a cushion pin which applies sufficient supporting force to a blank holder of a press molding apparatus even if the number of cushion pins and an arrangement region are restricted. A cushion pin (1A) has a cylindrical main body section including a plurality of cylindrical members (2) and annular members (3). The cylindrical members (2) are arranged in series in an axial direction, and the annular members (3) are disposed between the adjacent cylindrical members (2). A rod member (4) and a coil spring (5) are disposed in each the spring chambers of the main body section. The rod member (4) includes a rod-shaped part (4b) and a flange part (4a). The rod-shaped part (4b) has a diameter allowing the rod-shaped part (4b) to slidably penetrate through an opening (3a) of the annular member (3). The coil spring (5) biases the flange part (4a).

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.

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.

Provided is a method for manufacturing an iron core that enables reduction of variations in dimension of a plurality of metal plates that occur during pressing of the laminate of these metal plates. The method includes: a laminate preparation step of stacking a plurality of metal plates to prepare a laminate; a pressing step of giving a temperature gradient to the laminate and pressing the laminate with a pressing machine having a punch and a die; and a temperature-gradient removal step of removing the temperature gradient from the laminate. The pressing step gives the temperature gradient to the laminate so that the temperature rises from the punch-side to the die-side in the stacking direction of the laminate.

Provided is a method for manufacturing an iron core that enables reduction of variations in dimension of a plurality of metal plates that occur during pressing of the laminate of these metal plates. The method includes: a laminate preparation step of stacking a plurality of metal plates to prepare a laminate; a pressing step of giving a temperature gradient to the laminate and pressing the laminate with a pressing machine having a punch and a die; and a temperature-gradient removal step of removing the temperature gradient from the laminate. The pressing step gives the temperature gradient to the laminate so that the temperature rises from the punch-side to the die-side in the stacking direction of the laminate.