Abstract: A die cushion device includes four hydraulic cylinders that support a cushion pad, a die cushion load controller that controls each of the hydraulic cylinders and generates a die cushion load on the cushion pad, and a die cushion position controller that controls each of the hydraulic cylinders to control a position of the cushion pad. In a case where only a left part is produced with a left die by a press machine, the die cushion load controller performs die cushion load control on two hydraulic cylinders on the left side, and the die cushion position controller performs die cushion position control on two hydraulic cylinders on the right side.

Abstract: The press machine includes: a hydraulic cylinder configured to drive a slide; a plurality of hydraulic pumps/motors; a first port of each of which is connected to a first pressurizing chamber of the hydraulic cylinder; a plurality of servomotors axially connected to rotating shafts of the respective hydraulic pumps/motors respectively; a low-pressure accumulator to which second ports of the hydraulic pumps/motors are each connected; a high-pressure accumulator connected to a second pressurizing chamber of the hydraulic cylinder; and a slide position controller configured to control the servomotors so that a position of the slide matches a position corresponding to a slide position command signal based on the slide position command signal from a slide position commander and a slide position signal from a slide position detector.

Abstract: A press load measuring apparatus includes: strain gauges attached to respective columns of a press machine and configured to detect strains generated in the respective columns respectively in association with a press load acting on a slide of the press machine, an inertial force calculator configured to calculate a slide inertial force proportional to a product of a mass of a slide and a member connected to the slide and a slide acceleration detected by an acceleration detector, and a press load calculator configured to calculate press partial load signals before calibration based on a strain signals detected by the strain gauges, eliminate a slide inertial force signals from the press partial load signals before the calibration, and calculate calibrated press partial load signals.

Abstract: A die cushion device of a press machine includes a hydraulic cylinder that supports a cushion pad and generates die cushion force when a slide of the press machine descends, an orifice and a hydraulic pump/motor that are connected to each other in in parallel between a lower chamber of the hydraulic cylinder and a tank, a servo motor connected to a rotating shaft of the hydraulic pump/motor, and a control unit that controls torque of the servo motor to control the die cushion force, wherein a rotation direction of the servo motor switches from a first rotation direction in which the hydraulic pump/motor serves as a hydraulic motor to a second rotation direction in which the hydraulic pump/motor serves as a hydraulic pump, during generation of the die cushion force.

Abstract: A press system providing excellent energy efficiency for a whole press system and capable of achieving low prices is provided. A die cushion apparatus constituting a press system supports a cushion pad, includes a hydraulic cylinder which generates a die cushion load on the cushion pad when a slide of a press machine descends, the press machine includes a hydraulic cylinder which generates part of a press load on the slide when the slide descends. The pressure generation chamber of the hydraulic cylinder for generating a die cushion load and the pressure generation chamber of the hydraulic cylinder for generating part of the press load can communicate with each other via pipes and a first logic valve for a period during which the die cushion load acts.

Abstract: A double-blank detecting apparatus for a press machine that is provided with a die cushion apparatus and is configured to form blanks one by one automatically and repeatedly. The double-blank detecting apparatus includes: a position signal acquiring unit configured to acquire a slide position signal indicating a position of a slide of the press machine; a load signal acquiring unit configured to acquire a die cushion load signal indicating a die cushion load generated on a cushion pad of the die cushion apparatus; and a double-blank detector configured to detect a state in which a plurality of blanks are stacked as a double blank based on the slide position signal acquired by the position signal acquiring unit and the die cushion load signal acquired by the load signal acquiring unit.

Abstract: A press load measuring apparatus for a press machine of 1-point type includes: a plurality of strain gauges attached to the respective columns of the press machine, the plurality of strain gauges detecting respective strains generated in the respective columns in association with a press load acting on the slide; a bending moment calculator configured to calculate bending moments acting on respective columns based on an angle formed between a direction of movement of the slide and the connecting rod; and a press partial load calculator configured to calculate press partial load signals corresponding to the respective columns, an impact of bending strain components caused by the bending moments included in the strain signals being eliminated from the press partial load signals based on the bending moments acting on the respective columns detected by strain gauges attached to the respective columns.

Abstract: A cushion pin pressure equalizing device that can absorb a variation in height of a plurality of cushion pins and control a die cushion load highly accurately, a die cushion device, and a cushion pin pressure equalizing method are provided. An initial pressure in ascending-side pressurizing chambers of a pressure equalizing hydraulic cylinder group for absorbing a variation in height of cushion pins is controlled so as to be an appropriate pressure. The variation in height of the plurality of cushion pins can be absorbed within a shortest stroke of a slide after the slide comes into collision with a cushion pad so as to equalize die cushion loads that are applied individually to the cushion pins and a target die cushion load can be generated within the shortest stroke of the slide, whereby a response to application of the die cushion load can be stabilized without excessive delay.

Abstract: The double blank detecting device for a press machine uses a press machine with a die cushion device attached thereto, and automatically and repeatedly forms blank materials one by one. The double blank detecting device includes: a position signal acquiring unit that acquires a die cushion position signal indicating a position of a cushion pad of the die cushion device; a load signal acquiring unit that acquires a die cushion load signal indicating a die cushion load generated in the cushion pad of the die cushion device; and a double blank detecting unit that detects, as a double blank, a state where a plurality of the blank materials are overlapped, based on the die cushion position signal and the die cushion load signal that are acquired.

Abstract: A die cushion device includes four hydraulic cylinders that support a cushion pad, a die cushion load controller that controls each of the hydraulic cylinders and generates a die cushion load on the cushion pad, and a die cushion position controller that controls each of the hydraulic cylinders to control a position of the cushion pad. In a case where only a left part is produced with a left die by a press machine, the die cushion load controller performs die cushion load control on two hydraulic cylinders on the left side, and the die cushion position controller performs die cushion position control on two hydraulic cylinders on the right side.

Abstract: The press machine includes: a hydraulic cylinder configured to drive a slide; a plurality of hydraulic pumps/motors; a first port of each of which is connected to a first pressurizing chamber of the hydraulic cylinder; a plurality of servomotors axially connected to rotating shafts of the respective hydraulic pumps/motors respectively; a low-pressure accumulator to which second ports of the hydraulic pumps/motors are each connected; a high-pressure accumulator connected to a second pressurizing chamber of the hydraulic cylinder; and a slide position controller configured to control the servomotors so that a position of the slide matches a position corresponding to a slide position command signal based on the slide position command signal from a slide position commander and a slide position signal from a slide position detector.

Abstract: A part of kinetic energy during lowering of a slide of a press machine is converted into oil hydraulic energy by a first oil hydraulic cylinder, and the converted oil hydraulic energy (hydraulic oil having boosted first system pressure) is stored in a first accumulator. The hydraulic oil having the first system pressure stored in the first accumulator is discharged in knockout process, a second oil hydraulic cylinder that functions as a knockout cylinder is raised to perform knockout operation of a product worked by the press machine. Consequently, it is possible to perform knockout operation without using a dedicated driving source such as an oil pressure source and an air pressure source, and provide a low-cost hydraulic knockout device.

Abstract: A press load measuring apparatus includes: strain gauges attached to respective columns of a press machine and configured to detect strains generated in the respective columns respectively in association with a press load acting on a slide of the press machine, an inertial force calculator configured to calculate a slide inertial force proportional to a product of a mass of a slide and a member connected to the slide and a slide acceleration detected by an acceleration detector, and a press load calculator configured to calculate press partial load signals before calibration based on a strain signals detected by the strain gauges, eliminate a slide inertial force signals from the press partial load signals before the calibration, and calculate calibrated press partial load signals.

Abstract: A press load measuring apparatus for a press machine of 1-point type includes: a plurality of strain gauges attached to the respective columns of the press machine, the plurality of strain gauges detecting respective strains generated in the respective columns in association with a press load acting on the slide; a bending moment calculator configured to calculate bending moments acting on respective columns based on an angle formed between a direction of movement of the slide and the connecting rod; and a press partial load calculator configured to calculate press partial load signals corresponding to the respective columns, an impact of bending strain components caused by the bending moments included in the strain signals being eliminated from the press partial load signals based on the bending moments acting on the respective columns detected by strain gauges attached to the respective columns.

Abstract: To provide a die cushion device which is inexpensive, functional, and capable of locking completely (at or below the slide bottom dead center). The die cushion device includes a cushion pad, a hydraulic cylinder that moves the cushion pad up and down, and a hydraulic closed circuit connected to a die cushion pressure generation chamber of the hydraulic cylinder. The hydraulic closed circuit includes a cushion pad lowering pressure generation line and a second system pressure line in addition to a die cushion pressure generation line and a first system pressure line. When the cushion pad is locked at the bottom dead center, the cushion pad lowering pressure generation chamber is connected to the first system pressure line, and the die cushion pressure generation chamber is connected to the second system pressure line such that the cushion pad is held at or below the slide bottom dead center.

Abstract: A plurality of hydraulic cylinders capable of adjusting height direction positions of a plurality of die-cushion pins that are inserted into a plurality of die-cushion pin holes formed in a bolster, respectively, are arranged in a lattice state on a cushion pad, and the hydraulic cylinder faced with a die-cushion pin located below a projection surface of a blank holder in the plurality of hydraulic cylinders is selected. Then, by independently adjusting a height direction position of a piston rod of each of the selected hydraulic cylinders, respectively, the shim adjustment of substantially each of the die-cushion pins is realized.

Abstract: 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.

Abstract: A first member made of an insulating material and a jig with a protrusion narrowing toward a distal end side are prepared, and at least one of the first member and the jig is heated to a temperature at which the first member can melt and deform. After the jig is brought into contact with the first member with the first member and the plurality of protrusions facing each other, the jig is removed, and an intermediate body is formed including the first member formed with a plurality of recesses, and a plurality of conductive members passing through the first member and projecting into the recesses. A second member is prepared, openings of the plurality of recesses are closed, and the second member is hermetically joined to the intermediate body to form a plurality of internal spaces where electron is emitted, and forming a joined body.

Abstract: An electron tube includes a housing having an internal space airtightly sealed, and an electrode configured to generation or detection of energy by electron emission in the internal space. The housing has a main body part made of an insulating material and formed with a recess constituting the internal space, and a lid part fixed to the main body part so as to close an opening of the recess. The recess expands toward the opening side. The main body part is fixed with a penetrating member that is electrically connected to the electrode and passes through the main body part. The penetrating member has an internal space projecting part that projects from a bottom surface of the recess into the internal space.

Abstract: A double-blank detecting apparatus for a press machine that is provided with a die cushion apparatus and is configured to form blanks one by one automatically and repeatedly. The double-blank detecting apparatus includes: a position signal acquiring unit configured to acquire a slide position signal indicating a position of a slide of the press machine; a load signal acquiring unit configured to acquire a die cushion load signal indicating a die cushion load generated on a cushion pad of the die cushion apparatus; and a double-blank detector configured to detect a state in which a plurality of blanks are stacked as a double blank based on the slide position signal acquired by the position signal acquiring unit and the die cushion load signal acquired by the load signal acquiring unit.