Casting mold shaping method and casting mold shaping device

Abstract

A casting mold shaping method is provided which enables, in a three-stage squeeze step using an electric motor, quick and smooth switching from a second squeeze step to a third squeeze step. The casting mold shaping method includes: a first squeeze step of moving the pressing member toward a back surface of a pattern to an inside of a molding space; a second squeeze step of regulating an approach of the molding flask toward the pressing member side by the stopper device and moving the pattern and a pattern surface plate to the inside of the molding space; and a third squeeze step of releasing the regulation by the stopper device and moving the pressing member toward the back surface of the pattern to the inside of the molding space in a state where the movement of the output unit in the second squeeze step is continued.

1 . A casting mold shaping method using a casting mold shaping device, the casting mold shaping device comprising:
 a pressing member that presses casting sand charged in a molding space formed by a pattern surface plate, a pattern, a molding flask, an upper filling frame, and a lower filling frame placed on a squeezing table;   a driving mechanism that performs driving so as to bring the pressing member and the squeezing table close to each other and to separate the pressing member and the squeezing table from each other, and includes an output unit that relatively moves along a direction of pressing the pressing member;   an electric motor that drives the driving mechanism;   a stopper device capable of regulating a relative movement in a vertical direction of the molding flask, the upper filling frame, and the lower filling frame with respect to the casting sand charged in the molding space; and   a pressure adjustment device that performs adjustment so as to reduce force of the driving mechanism in a pressing direction directed to the output unit and causes the pressing member to generate predetermined pressing force necessary to press the casting sand;   the casting mold shaping method comprising:   a first squeeze step of driving the driving mechanism to move the output unit, and relatively moving the pressing member from above the pattern toward a back surface of the pattern to an inside of the molding space so as to smooth an upper surface of the casting sand charged into the molding space;   a second squeeze step of regulating an approach of the molding flask, the upper filling frame, and the lower filling frame to the pressing member side by the stopper device, driving the driving mechanism to move the output unit, and relatively moving the pattern and the pattern surface plate from the pattern side to the inside of the molding space to thereby press the casting sand; and   a third squeeze step of releasing regulation of the molding flask by the stopper device and relatively moving the pressing member from above the pattern toward the back surface of the pattern to the inside of the molding space in a state where the movement of the output unit by the driving mechanism in the second squeeze step is continued to thereby press the casting sand.   
     
     
         2 . The casting mold shaping method according to  claim 1 , wherein
 the stopper device includes a stopper cylinder device operating by hydraulic pressure, a stopper rod that advances and retracts so as to be able to come into contact with the upper filling frame in order to regulate an approach to the pressing member side by the stopper cylinder device, a stopper rod control device that controls the advance and retract of the stopper rod based on a back pressure of the stopper cylinder device, and an output device that outputs a predetermined stopper rod holding force value that is a back pressure value generated when a height position of a lower end of the molding flask coincides with a height position of an upper surface of the pattern surface plate, and   in the second squeeze step, in a case where the back pressure becomes the stopper rod holding force value, the third squeeze step is performed by setting the back pressure to zero by the stopper rod control device.   
     
     
         3 . A casting mold shaping device comprising:
 a pressing member that presses casting sand charged in a molding space formed by a pattern surface plate, a pattern, a molding flask, an upper filling frame, and a lower filling frame placed on a squeezing table;   a driving mechanism that performs driving so as to bring the pressing member and the squeezing table close to each other and to separate the pressing member and the squeezing table from each other, and includes an output unit that relatively moves along a direction of pressing the pressing member;   an electric motor that drives the driving mechanism;   a stopper device capable of regulating a relative movement in a vertical direction of the molding flask, the upper filling frame, and the lower filling frame with respect to the casting sand charged in the molding space;   a pressure adjustment device that performs adjustment so as to reduce force of the driving mechanism in a pressing direction directed to the output unit and causes the pressing member to generate predetermined pressing force necessary to press the casting sand; and   a control device that controls the driving mechanism, the stopper device, and the pressure adjustment device; wherein   the control device includes:   a first squeeze unit that drives the driving mechanism to move the output unit, and relatively moves the pressing member from above the pattern toward a back surface of the pattern to an inside of the molding space so as to smooth an upper surface of the casting sand charged into the molding space;   a second squeeze unit that regulates an approach of the molding flask, the upper filling frame, and the lower filling frame to the pressing member side by the stopper device, drives the driving mechanism to move the output unit, and relatively moves the pattern and the pattern surface plate from the pattern side to the inside of the molding space to thereby press the casting sand; and   a third squeeze unit that releases regulation of the molding flask by the stopper device and relatively moves the pressing member from above the pattern toward the back surface of the pattern to the inside of the molding space in a state where the movement of the output unit by the driving mechanism in the second squeeze unit is continued to thereby press the casting sand.   
     
     
         4 . The casting mold shaping device according to  claim 3 , wherein
 the stopper device includes a stopper cylinder device operating by hydraulic pressure, a stopper rod that advances and retracts so as to be able to come into contact with the upper filling frame in order to regulate an approach to the pressing member side by the stopper cylinder device, and a stopper rod control device that controls the advance and retract of the stopper rod based on back pressure of the stopper cylinder device, and   the stopper rod control device includes a back pressure sensor that detects the back pressure of the stopper cylinder device, a pressure control valve that controls a value of the back pressure based on a value detected by the back pressure sensor, and a pressure command amplifier that instructs set pressure of the pressure control valve.   
     
     
         5 . The casting mold shaping device according to  claim 4 , wherein a plurality of the stopper cylinder devices of the stopper device is provided
 corresponding to the stopper rod, and each of the stopper cylinder devices is provided with a cut valve that blocks inflow and outflow of oil to and from each of the stopper cylinder devices at a time of mold release.