Patent Application
20250214134
The following relates to a casting mold shaping method in which a pressurizing device using an electric motor is used to form a mold by squeezing casting sand in a molding flask in the three stages: a back side preliminary squeeze, a pattern surface side squeeze, and a back side main squeeze, and relates to a casting mold shaping device for performing the casting mold shaping method.
Conventionally, a casting mold shaping device for manufacturing a mold commonly uses an actuator including a hydraulic cylinder to press (squeeze) casting sand in a molding flask.
However, in most cases, a hydraulic pressure generation device which functions as a pressure source of the hydraulic cylinder, is operated at all times during the operation of a facility, and is a device that uses a particularly large amount of power, and thus a large running cost is required.
Therefore, in recent years, in order to save energy by reducing power consumption, a de-hydraulic cylinder has been examined, and the electrification of actuators has been promoted.
As an example of such electrification, Japanese Patent Application Laid-Open No. H8-164444 describes using a straight-moving type electric cylinder using a servomotor to lift and lower a squeezing plate (pressing member).
However, in order to increase the accuracy and uniformity of a mold to be formed, the mold is formed by a three-stage squeeze in some cases. Here, the three-stage squeeze is to perform a first squeeze step of relatively moving the pressing member toward a back surface of a pattern into a molding space (back side preliminary squeeze step), a second squeeze step of relatively moving the pattern and a pattern surface plate from the pattern side into the molding space (pattern surface side squeeze step), and a third squeeze step of relatively moving the pressing member from above the pattern toward the back surface of the pattern into the molding space (back side main squeeze step).
In a case where a mold is formed by the three-stage squeeze using a pressurizing device (a driving mechanism and a pressing member) using an electric motor, in the second squeeze step, a step of closing an oil passage of a stopper cylinder and bringing the pressing member close to and pressing against casting sand charged into the molding space from the pattern side is performed.
Then, the lowering speed of the pressurizing device is reduced and stopped at a height at which the lower surface of the molding flask and the pattern surface coincide with each other by lowering a lower filling frame, the oil passage of the stopper cylinder is opened to perform the third squeeze step, and the pressing member is brought close to and pressed against the casting sand charged into the molding space from the back surface side of the pattern.
However, in a case where the second squeeze step is performed using the pressurizing device (the driving mechanism and the pressing member) using the electric motor, if the electric motor is stopped by external force at a height position where the lower surface of the molding flask and the pattern surface (the upper surface of the pattern surface plate) coincide with each other, an excessive impact is generated, which is difficult. Therefore, in order to ensure accurate positioning at the target stop position, it is necessary to decelerate and stop the lowering of the pressurizing device, which causes a problem of time loss.
Embodiments of the present invention have been made in view of such conventional problems, and an aspect of embodiments of the present invention is to provide a casting mold shaping method which enables, in a three-stage squeeze step using an electric motor, quick and smooth switching from the second squeeze step to the third squeeze step, and a casting mold shaping device using the mold shaping method.
According to a casting mold shaping method of a first aspect of embodiments of the present invention, a casting mold shaping device to be used includes 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, and 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.
The casting mold shaping device also includes 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 includes 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.
According to the configuration, in the second squeeze step, the third squeeze step can be performed by releasing the regulation of the molding flask by the stopper device without stopping the moving output unit. Therefore, the third squeeze step can be performed quickly and smoothly without impact or extra time.
According to a casting mold shaping method of a further aspect of embodiments of the present invention, in the casting mold shaping method of the first aspect, the stopper device includes a stopper cylinder device, 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.
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.
According to the configuration, the back pressure of the stopper rod is set to zero based on the stopper rod holding force value generated when the height position of the lower end of the molding flask coincides with the height position of the upper surface of the pattern surface plate. Therefore, the third squeeze step can be performed with the height positions of the lower end of the molding flask and the upper surface of the pattern surface plate made to be the same.
According to a casting mold shaping device of a further aspect of embodiments of the present invention, the casting mold shaping device includes 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, and 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.
The casting mold shaping device also includes 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.
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.
The control device includes 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.
The control device includes 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.
According to the configuration, in the second squeeze unit, the third squeeze unit can be performed by releasing the regulation of the molding flask by the stopper device without stopping the moving output unit. Therefore, the third squeeze unit can be performed quickly and smoothly without spending extra time for impact prevention.
According to a casting mold shaping device of a further aspect of embodiments of the present invention, in the casting mold shaping device of the third aspect, the stopper device includes a hydraulic cylinder device, 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 hydraulic cylinder device, and a stopper rod control device that controls the advance and retract of the stopper rod based on back pressure of the hydraulic cylinder device, and the stopper rod control device includes a back pressure sensor that detects the back pressure of the hydraulic 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.
According to the configuration, the back pressure of the stopper rod is set to zero based on the stopper rod holding force value generated when the height position of the lower end of the molding flask coincides with the height position of the upper surface of the pattern surface plate. Therefore, the third squeeze unit can be performed with the height positions of the lower end of the molding flask and the upper surface of the pattern surface plate made to be the same.
According to a casting mold shaping device of a further aspect of embodiments of the present invention, in the casting mold shaping device of the third or fourth aspect, a plurality of the hydraulic cylinder devices of the stopper device is provided corresponding to the stopper rod, and each of the hydraulic cylinder devices is provided with a cut valve that blocks inflow and outflow of oil to and from each of the hydraulic cylinders at a time of mold release.
According to the configuration, the position of each stopper rod can be maintained horizontally by blocking the inflow and outflow of oil to and from the hydraulic cylinder at the time of mold release. Therefore, the molding flask can be maintained horizontally at the time of mold release, which prevents defects such as chipping of the mold caused by tilting the molding flask. The “mold release” in this case refers to separating the mold (with the molding flask) from the pattern and the pattern surface plate.
Some of the embodiments will be described in detail, with references to the following Figures, wherein like designations denote like members, wherein:
A first embodiment of a casting mold shaping device and a casting mold shaping method according to the present invention will be described below with reference to
As illustrated in
Furthermore, in a first oil passage 69 and a second oil passage 79, a hydraulic pump HP side, which is the starting point side of the hydraulic conveyance, is referred to as an upstream side, and the end point side of the hydraulic conveyance is referred to as a downstream side.
The squeezing table 2 has a carrier plate CP, to which a pattern CM and a pattern surface plate MP are fixed, placed thereon, and faces the pressing member 3 described later to serve to receive the pressing force during squeezing. The squeezing table 2 in the present embodiment is a stand having a rectangular cross section fixed to a base 82. A seating portion 2a protruding in the horizontal direction with a predetermined width is circumferentially provided in an upper peripheral portion of the squeezing table 2. The upper end surface of the seating portion 2a is formed with a step having a predetermined height lower than that of the upper end surface of the squeezing table 2.
On the squeezing table 2, from the bottom, the carrier plate CP, a lower filling frame BF, the pattern surface plate MP, a molding flask CF, and an upper filling frame TF are stacked and placed.
The pattern surface plate MP, the lower filling frame BF, the molding flask CF, and the upper filling frame TF are stacked to form a “molding space MS”. Casting sand CS is charged into the molding space MS, and the charged casting sand CS is compacted by the pressing member 3 to form a mold.
The carrier plate CP is assembled with the pattern surface plate MP to which the pattern CM is fixed as described above, conveyed by a conveying device (not illustrated), carried onto the squeezing table 2, and positioned at a position for squeezing.
The carrier plate CP is formed in, for example, a rectangular thick plate made of iron. A holding recess CP1 for holding the pattern surface plate MP is formed on the upper surface of the carrier plate CP, and a flange portion CP2 protruding laterally with a predetermined width is formed around the lower portion of the carrier plate CP. Through holes CP3 are formed in four corners of the flange portion CP2 along the vertical direction. A guide rod GR described later is loosely fitted into each through hole CP3.
The lower filling frame BF is used by being stacked under the molding flask CF in order to secure the casting sand CS before compression when the pattern surface side squeeze is applied.
The lower filling frame BF is made of, for example, iron and formed in a rectangular frame shape. Holding holes BF1 that are open downward and extend in the vertical direction are provided at four corners of the lower filling frame BF. The upper end portions of a coil spring S and the guide rod GR described later are inserted into each holding hole BF1.
For example, a female screw hole is formed in a ceiling portion of the holding hole BF1, and a male screw portion formed at the tip of the upper end portion of the guide rod GR described later is screwed into the female screw hole and assembled therein.
The coil spring S is placed to extend along the vertical direction between the lower surface of the ceiling portion of each of the holding holes BF1 and the upper surface of the opposing flange portion CP2. The coil spring S is disposed in a compressed state, and is provided so as to bias the lower filling frame BF in a direction of moving the lower filling frame BF away from the carrier plate CP. The guide rod GR is inserted into the center of each coil spring S, which allows the lower filling frame BF to move up and down in the horizontal state.
The guide rod GR is made of, for example, iron and formed in a bar shape, and includes a bar-shaped main body portion GR1, a lower head portion GR2 having a diameter larger than that of the bar-shaped main body portion GR1, and the male screw portion formed at the upper end portion.
The lower head portion GR2 is engaged with the lower end portion of the through hole CP3 of the carrier plate CP to regulate upward removal of the guide rod GR from the through hole CP3.
In the pattern surface side squeeze step, when the lower filling frame BF slides on the outer periphery of the carrier plate CP to move downward, the lower end of the lower head portion GR2 comes into contact with the upper surface of the seating portion 2a of the squeezing table 2, so that the downward movement of the lower filling frame BF is regulated.
Setting is so made that, when the lower end of the lower head portion GR2 comes into contact with the upper surface of the seating portion 2a of the squeezing table 2, the height position of an upper surface MP1 of the pattern surface plate MP coincides with the height position of a lower end CF1 of the molding flask CF.
Further, when the lower end of the lower head portion GR2 comes into contact with the upper surface of the seating portion 2a of the squeezing table 2, a stopper rod holding force value described later is produced in the back pressure of a stopper cylinder device 71 of the stopper device 7. The lower head portion GR2 and the seating portion 2a constitute an output device.
The pattern surface plate MP is made of, for example, iron, formed in a plate shape, assembled with the pattern CM, and used for molding. Since the pattern surface plate MP is a well-known technique, the description thereof will be omitted.
The molding flask CF is a frame that surrounds the periphery and holds the casting sand CS when a mold is formed. The molding flask CF is made of, for example, iron, formed in a rectangular frame shape, and stacked on the lower filling frame BF. Since the molding flask CF is a well-known technique, the description thereof will be omitted.
The upper filling frame TF is stacked and held on the molding flask CF so that the casting sand CS, which is charged into the molding space MS in extra to use the pressing stroke for squeezing, does not spill out.
The upper filling frame TF is made of, for example, iron and formed in a rectangular frame shape. After the molding is finished in the molding flask CF, the upper filling frame TF is removed from the molding flask CF.
The pressing member 3 presses the casting sand CS charged into the molding space MS that is defined by the upper filling frame TF, the molding flask CF, the lower filling frame BF, and the pattern surface plate MP, thereby compacting the casting sand CS and forming a mold using the sand. The casting sand CS is pressed by downward force output from an output unit 42 of the driving mechanism 4 described later.
The pressing member 3 in the present embodiment is configured by a plurality of squeezing feet 31. Each squeezing foot 31 includes a pressing portion 31a having a substantially cubic shape and a rod portion 31b, and a plurality of the pressing portions 31a is gathered and arranged in a rectangular shape so as to press the casting sand CS with lower surfaces of the pressing portions 31a.
A lower end of the bar-shaped rod portion 31b is integrally connected to an upper portion of each pressing portion 31a. An upper end of the rod portion 31b is connected to a piston portion 61b of the pressure adjustment device 6 described later. The rod portion 31b is configured to advance and retract downwardly from an opening of a cylinder portion 61a of the pressure adjustment device 6 described later.
The electric motor 5 drives the driving mechanism 4 described later.
As the electric motor 5, for example, it is possible to use an induction motor. The induction motor is a type of motor that does not require complicated control like a servomotor. A transmission (not illustrated) is provided on an output shaft (not illustrated) of the electric motor 5, and an output portion of the transmission is connected to the driving mechanism 4 described later via a coupling (not illustrated).
The driving mechanism 4 transmits rotational torque of the electric motor 5 to the pressing member 3 as pressing force.
Although the detailed structure of the driving mechanism 4 is not illustrated, the driving mechanism 4 includes a motion conversion device 41 and the output unit 42.
The motion conversion device 41 converts the rotational motion of the electric motor 5 into a linear motion of the output unit 42.
Examples of the motion conversion device 41 include an eccentric wheel and a slider crank. In a case where the rotational motion of the electric motor 5 is converted into the linear motion of the output unit 42, the force, direction, and speed fluctuate. These fluctuations are adjusted by the pressure adjustment device 6 described later such that the pressing member 3 generates appropriate pressing force.
The output unit 42 outputs the motion converted by the motion conversion device 41, and linearly reciprocates in the vertical direction. A lower end of the output unit 42 is connected to an upper end of a raising and lowering frame 611 of the pressure adjustment device 6 described later with a bolt (not illustrated) or the like.
The pressure adjustment device 6 is provided between the output unit 42 and the pressing member 3.
The pressure adjustment device 6 performs adjustment so as to reduce the fluctuating force of the driving mechanism 4 to thereby allow the pressing member 3 to generate stable and necessary predetermined pressing force.
The pressure adjustment device 6 includes a hydraulic cylinder device 61, a hydraulic pump HP, a first pressure sensor 64, a first pressure control valve 65, a first pressure command amplifier 66, and a first electromagnetic directional control valve 68.
The hydraulic cylinder device 61 includes the raising and lowering frame 611, the cylinder portion 61a, and the piston portion 61b. The raising and lowering frame 611 is made of, for example, iron and formed in a three-dimensionally square shape, and a plurality of the cylinder portions 61a formed in a cylindrical shape and extending in the vertical direction is provided side by side to form a rectangular shape inside the raising and lowering frame 611.
The stopper cylinder device 71 of the stopper device 7 described later is provided at each of four corners of the raising and lowering frame 611.
The cylinder portions 61a of the hydraulic cylinder device 61 are provided so as to correspond to the plurality of squeezing feet 31 described above. As described above, the upper end of the rod portion 31b of the squeezing foot 31 is connected to the piston portion 61b.
In the plurality of hydraulic cylinder devices 61, the cylinder portions 61a are communicated with each other through the first oil passage 69, and hydraulic force by each hydraulic cylinder device 61 uniformly acts on all the cylinder portions 61a.
Hydraulic oil is filled in the cylinder portions 61a above the piston portions 61b, and when the squeezing feet 31 press the casting sand CS with the pressing portions 31a at the tip thereof, the pressing force is determined depending on the hydraulic pressure (that is, back pressure described later acting on the piston portions 61b) in the cylinder portions 61a. The plurality of cylinder portions 61a is communicated with one hydraulic pump HP through the first oil passage 69.
The first pressure sensor 64 is provided between the cylinder portions 61a and the hydraulic pump HP. The first pressure sensor 64 detects the pressure on the back pressure side of the hydraulic cylinder device 61. A branch oil passage connected to the first pressure control valve 65 is provided between the first pressure sensor 64 and the hydraulic pump HP. The first pressure control valve 65 functions as a pressure reducing valve that reduces the pressure based on a specific pressure value instructed from the connected first pressure command amplifier 66.
The first pressure control valve 65 reduces a fluctuating pressure to be inputted to the output unit 42 and the raising and lowering frame 611 by the driving mechanism 4 so as to become a constant pressure in the back pressure of the hydraulic cylinder device 61. The pressure to be inputted to the output unit 42 and the raising and lowering frame 611 by the driving mechanism 4 is set to a value slightly higher than the pressure required for pressing and is executed. The pressure to be inputted by the driving mechanism 4 is set by the calculation based on the output of the electric motor 5, the structure of the motion conversion device 41, and the like. For example, in a case where the pressure required for pressing is 10 MPa, the pressure to be inputted by the driving mechanism 4 is set to 12 MPa.
When the squeezing feet 31 apply pressure to the casting sand CS, the pressure adjustment device 6 detects the back pressure acting on a rear end side of the squeezing feet 31 by the secondary-side first pressure sensor 64, and in a case where the detected back pressure exceeds a predetermined pressure value, the pressure adjustment device 6 discharges oil from the first oil passage 69 communicating with the cylinder portions 61a to thereby reduce the back pressure to a set pressure value.
The hydraulic pump HP is disposed at a terminal portion of the first oil passage 69 via a check valve CV. The hydraulic pump HP is shared with the second oil passage 79 described later. The hydraulic pump HP is used to return the squeezing feet 31 retracted to the cylinder portions 61a side to an advancing end that is the initial position during the operation of pressing the casting sand CS described later. The pressure used to return the squeezing feet 31 to the initial position may be, for example, approximately 1 MPa, and thus, the amount of power for driving the hydraulic pump HP can be extremely small.
The stopper device 7 is provided so as to be positioned above the upper filling frame TF during molding. By regulating the relative movement in the vertical direction of the molding flask CF, the upper filling frame TF, and the lower filling frame BF with respect to the casting sand CS charged into the molding space MS, it is used to perform the squeeze step (second squeeze step) from the pattern surface side.
The stopper device 7 includes the stopper cylinder device 71, a stopper rod 72, and a stopper rod control device 73.
The stopper cylinder device 71 includes a stopper cylinder portion 71a and a stopper piston portion 71b. The stopper rod 72 is made of, for example, iron and formed in a bar shape.
The stopper piston portion 71b is connected to the upper end of the stopper rod 72, and the stopper rod 72 can advance and retract with respect to the stopper cylinder portion 71a whose lower portion is open.
The lower end of the stopper rod 72 is configured to come into contact with an upper end surface of the upper filling frame TF when the raising and lowering frame 611 is lowered in the molding step.
The stopper cylinder portions 71a are communicated with each other through the second oil passage 79, and hydraulic force applied to the stopper rods 72 uniformly acts on the four stopper cylinder portions 71a.
Hydraulic oil is filled in the stopper cylinder portions 71a above the stopper piston portions 71b, and when the stopper rods 72 press the upper filling frame TF, the pressing force is regulated depending on the hydraulic pressure (that is, back pressure described later acting on the stopper piston portions 71b) in the stopper cylinder portions 71a.
The four stopper cylinder portions 71a are communicated with one hydraulic pump HP through the second oil passage 79.
The first oil passage 69 and the second oil passage 79 are connected on the downstream side of the check valve CV before the hydraulic pump HP, and the hydraulic oil is supplied by one hydraulic pump HP.
The stopper rod control device 73 controls advance and retract of the stopper rods 72.
The stopper rod control device 73 includes a second pressure sensor 74, a second pressure control valve 75, a second pressure command amplifier 76, a cut valve 77, and a second electromagnetic directional control valve 78.
The second pressure sensor 74 is provided between the stopper cylinder portions 71a and the hydraulic pump HP. The second pressure sensor 74 detects the pressure on the back pressure side of the stopper cylinder device 71. A branch oil passage connected to the second pressure control valve 75 is provided between the second pressure sensor 74 and the hydraulic pump HP. The second pressure control valve 75 performs back pressure control based on a specific pressure value instructed from the connected second pressure command amplifier 76.
The second pressure command amplifier 76 controls the discharge amount of the second pressure control valve 75 based on a command from a control device.
The cut valve 77 is provided between each of the stopper cylinder portions 71a and the second pressure sensor 74 in the second oil passage 79.
Each cut valve 77 blocks inflow and outflow of the hydraulic oil to and from the stopper cylinder portions 71a. Each cut valve 77 is implemented by an electromagnetic directional control valve, and includes two ports of a shut-off position at which the second oil passage 79 is shut off and a circulation position at which the circulation in the second oil passage 79 is allowed. The operation is controlled by the control device.
The second electromagnetic directional control valve 78 includes two ports of a shut-off position at which the second oil passage 79 is shut off and a circulation position at which the circulation in the oil passage is allowed, and the operation is controlled by the control device.
A structure body 8 plays a role of supporting the squeezing table 2, the pressing member 3, the driving mechanism 4, the electric motor 5, and the pressure adjustment device 6.
The structure body 8 is made of, for example, iron and formed in a turret shape, and includes a top plate portion 81, a base 82, and a support column 83.
The base 82 is formed by a rectangular-shaped plate, and the columnar-shaped support columns 83 are provided to stand from four corners of the base 82.
The support columns 83 support the rectangular-shaped top plate portion 81 that is horizontally provided, at four corners. A rectangular through-mounting hole 81a is provided at a central portion of the top plate portion 81, and the driving mechanism 4 passes through the through-mounting hole 81a and is fixed.
The control device (not illustrated) drives the electric motor 5 and controls the position of the driving mechanism 4. The control device also controls the discharge amount of the first pressure control valve 65 via the first pressure command amplifier 66 based on a signal of the first pressure sensor 64. The control device controls the discharge amount of the second pressure control valve 75 via the second pressure command amplifier 76 based on a signal of the second pressure sensor 74.
An operation of the casting mold shaping device 1 will be described below with reference to
First,
Below the pressing member 3, a so-called molding space MS is formed by stacking the carrier plate CP, the lower filling frame BF, the molding flask CF, and the upper filling frame TF on the squeezing table 2. The casting sand CS is charged into the molding space MS by a charging device (not illustrated). The casting sand CS is piled up to the position of the upper end portion of the upper filling frame TF.
Each squeezing foot 31 of the pressing member 3 driven by the hydraulic pump HP is held at the lowermost end with respect to the cylinder portion 61a in a state of being pressed by the hydraulic pressure in the cylinder portion 61a. Similarly, the stopper rod 72 is pressed by the hydraulic pressure in the stopper cylinder portion 71a and held at the lowermost position. In addition, the first electromagnetic directional control valve 68 and the second electromagnetic directional control valve 78 are positioned at the ports in the closed position.
The control device prepares for causing the driving mechanism 4 to output with the calculated numerical value so that the pressing member 3 performs pressing with the initial pressing force (Step 101, hereinafter referred to as “S101”).
Next, the control device sets the second pressure control valve 75 used for the stopper cylinder device 71 to zero pressure, and sets the first pressure control valve 65 used for the squeezing feet 31 to back side preliminary squeeze pressure (S102).
Here, the “back side preliminary squeeze pressure” is a squeeze performed by bringing the pressing member 3 close from the back side of the pattern CM, and is squeeze pressure performed with small force to level the upper surface of the casting sand CS.
Then, the control device drives the electric motor 5 to lower the raising and lowering frame 611 by the driving mechanism 4 as illustrated in
When pressing the casting sand CS, the pressing portion 31a presses the casting sand CS at predetermined necessary pressure. At this time, in a case where pressing force with predetermined pressure or more is applied, such a case is detected by the first pressure sensor 64, and oil that generates excessive pressure is discharged by the first pressure control valve 65 so as to reduce the pressure. This enables squeezing with desired pressing force.
Next, in a case where the first pressure sensor 64 used for the squeezing feet 31 detects a back side preliminary squeeze pressure value (S104), the control device sets the second pressure control valve 75 used for the stopper cylinder device 71 to stopper rod holding pressure, and sets the first pressure control valve 65 used for the squeezing feet 31 to pattern surface side squeeze pressure (S105).
The “stopper rod holding pressure” means the following pressure. In the pattern surface side squeeze described later, the stopper rod 72 moves the molding flask CF downward with respect to the casting sand CS while resisting the biasing force of the coil spring S by the hydraulic pressure of the stopper cylinder portion 71a. At this time, the lower filling frame BF also slides downward with respect to the carrier plate CP. Then, when the lower head portion GR2 of the guide rod GR comes into contact with the seating portion 2a of the squeezing table 2, the downward sliding of the lower filling frame BF with respect to the carrier plate CP stops.
Accordingly, the pressure based on the reaction force from the squeezing table 2 acts on the stopper rod 72, and the pressure value of the hydraulic pressure in the stopper cylinder portion 71a rapidly increases. The pressure generated at this time is the stopper rod holding pressure detected as the back pressure.
Further, the position at which the lower head portion GR2 of the guide rod GR comes into contact with the seating portion 2a of the squeezing table 2 is set such that the height position of the lower end CF1 of the molding flask CF and the height position of the upper surface MP1 of the pattern surface plate MP coincide with each other.
Then, as illustrated in
Next, in a case where the second pressure sensor 74 used for the stopper cylinder device 71 detects a stopper rod holding pressure value (S107), the control device sets the second pressure control valve 75 used for the stopper cylinder device 71 to zero pressure, and sets the first pressure control valve 65 used for the squeezing feet 31 to back side main squeeze pressure (S108).
Then, as illustrated in
Next, in a case where the first pressure sensor 64 used for the squeezing feet 31 detects a back side main squeeze pressure value (S110), the control device sets the first pressure control valve 65 used for the squeezing feet 31 to zero pressure (S111). The control device then stops the lowering of the raising and lowering frame 611.
Then, as illustrated in
Then, as illustrated in
Then, the control device turns off the cut valves 77 and switches the first electromagnetic directional control valve 68 and the second electromagnetic directional control valve 78 to ports in communication positions at which communication with the hydraulic pump HP is allowed (S114). Hydraulic oil is supplied to the hydraulic cylinder devices 61 and the stopper cylinder devices 71 by the hydraulic pump HP, and the piston portions 61b and the stopper piston portions 71b are returned to the lower end positions. Thereafter, the first electromagnetic directional control valve 68 and the second electromagnetic directional control valve 78 are switched to the ports in the closed position to prepare for the start of the squeeze step.
After that, the same steps are repeated.
As is clear from the above description, according to the casting mold shaping method of embodiments of the present invention using the casting mold shaping device 1 of the embodiment of the present invention, the casting mold shaping device 1 to be used includes the pressing member 3 that presses the casting sand CS charged in the molding space MS formed by the pattern surface plate MP, the pattern CM, the molding flask CF, the upper filling frame TF, and the lower filling frame BF placed on the squeezing table 2, and the driving mechanism 4 that performs driving so as to bring a distance between the pressing member 3 and the squeezing table 2 close to each other and to separate the pressing member 3 and the squeezing table 2 from each other, and includes the output unit 42 that relatively moves along a direction of pressing the pressing member 3.
The casting mold shaping device 1 includes the electric motor 5 that drives the driving mechanism 4, the stopper device 7 that is capable of regulating a relative movement in the vertical direction of the molding flask CF, the upper filling frame TF, and the lower filling frame BF with respect to the casting sand CS charged in the molding space MS, and the pressure adjustment device 6 that performs adjustment so as to reduce force of the driving mechanism 4 in the pressing direction directed to the output unit 42 and causes the pressing member 3 to generate predetermined pressing force necessary to press the casting sand CS.
The casting mold shaping method includes the first squeeze step of driving the driving mechanism 4 to move the output unit 42, and relatively moving the pressing member 3 from above the pattern CM toward the back surface of the pattern CM to the inside of the molding space MS so as to smooth the upper surface of the casting sand CS charged into the molding space MS.
The casting mold shaping method includes the second squeeze step of regulating an approach of the molding flask CF, the upper filling frame TF, and the lower filling frame BF to the pressing member 3 side by the stopper device 7, driving the driving mechanism 4 to move the output unit 42, and relatively moving the pattern CM and the pattern surface plate MP from the pattern CM side to the inside of the molding space MS to thereby press the casting sand CS.
The casting mold shaping method includes the third squeeze step of releasing regulation of the molding flask CF by the stopper device 7 and relatively moving the pressing member 3 from above the pattern CM toward the back surface of the pattern CM to the inside of the molding space MS in a state where the movement of the output unit 42 by the driving mechanism 4 in the second squeeze step is continued to thereby press the casting sand CS.
According to the configuration, in the second squeeze step, the third squeeze step can be performed by releasing the regulation of the molding flask CF by the stopper device 7 without stopping the moving output unit 42. Therefore, the third squeeze step can be performed quickly and smoothly without impact or extra time.
In addition, the stopper device 7 includes the stopper cylinder device 71, the stopper rod 72 that advances and retracts so as to be able to come into contact with the upper filling frame TF in order to regulate the approach to the pressing member 3 side by the stopper cylinder device 71, and the stopper rod control device 73 (second pressure sensor 74, second pressure control valve 75, second pressure command amplifier 76) that controls the advance and retract of the stopper rod 72 based on the back pressure of the stopper cylinder device 71.
The stopper device 7 includes the output device (lower head portion GR2, seating portion 2a) that outputs a predetermined stopper rod holding force value that is a back pressure value generated when the height position of the lower end CF1 of the molding flask CF coincides with the height position of the upper surface MP1 of the pattern surface plate MP.
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 73 (second pressure sensor 74, second pressure control valve 75, second pressure command amplifier 76).
According to the configuration, the back pressure of the stopper cylinder device 71 is set to zero based on the stopper rod holding force value generated when the height position of the lower end CF1 of the molding flask CF coincides with the height position of the upper surface MP1 of the pattern surface plate MP. Therefore, the third squeeze step can be performed with the height positions of the lower end CF1 of the molding flask CF and the upper surface MP1 of the pattern surface plate MP made to be the same.
Further, the casting mold shaping device 1 includes the pressing member 3 that presses the casting sand CS charged in the molding space MS formed by the pattern surface plate MP, the pattern CM, the molding flask CF, the upper filling frame TF, and the lower filling frame BF placed on the squeezing table 2. and the driving mechanism 4 that performs driving so as to bring a distance between the pressing member 3 and the squeezing table 2 close to each other and to separate the pressing member 3 and the squeezing table 2 from each other, and includes the output unit 42 that relatively moves along a direction of pressing the pressing member 3.
The casting mold shaping device 1 includes the electric motor 5 that drives the driving mechanism 4, the stopper device 7 that is capable of regulating a relative movement in the vertical direction of the molding flask CF, the upper filling frame TF, and the lower filling frame BF with respect to the casting sand CS charged in the molding space MS, the pressure adjustment device 6 that performs adjustment so as to reduce force of the driving mechanism 4 in the pressing direction directed to the output unit 42 and causes the pressing member 3 to generate predetermined pressing force necessary to press the casting sand CS, and the control device that controls the driving mechanism 4, the stopper device 7, and the pressure adjustment device 6.
The control device includes a first squeeze unit that drives the driving mechanism 4 to move the output unit 42, and relatively moves the pressing member 3 from above the pattern CM toward the back surface of the pattern CM to the inside of the molding space MS so as to smooth the upper surface of the casting sand CS charged into the molding space MS.
The control device includes a second squeeze unit that regulates an approach of the molding flask CF, the upper filling frame TF, and the lower filling frame BF to the pressing member 3 side by the stopper device 7, drives the driving mechanism 4 to move the output unit 42, and relatively moves the pattern CM and the pattern surface plate MP from the pattern CM side to the inside of the molding space MS to thereby press the casting sand CS.
The control device includes a third squeeze unit that releases regulation of the molding flask CF by the stopper device 7 and relatively moves the pressing member 3 from above the pattern CM toward the back surface of the pattern CM to the inside of the molding space MS in a state where the movement of the output unit 42 by the driving mechanism 4 in the second squeeze unit is continued to thereby press the casting sand CS.
According to the configuration, in the second squeeze unit, the third squeeze unit can be performed by releasing the regulation of the molding flask CF by the stopper device 7 without stopping the moving output unit 42. Therefore, the third squeeze unit can be performed quickly and smoothly without impact or extra time.
In addition, the stopper device 7 includes the stopper cylinder device 71 operating by hydraulic pressure, the stopper rod 72 that advances and retracts so as to be able to come into contact with the upper filling frame TF in order to regulate an approach to the pressing member 3 side by the stopper cylinder device 71, and the stopper rod control device 73 (second pressure sensor 74, second pressure control valve 75, second pressure command amplifier 76) that controls the advance and retract of the stopper rod 72 based on back pressure of the stopper cylinder device 71, and the stopper rod control device 73 includes the second pressure sensor 74 as the back pressure sensor that detects the back pressure of the stopper cylinder device 71, the second pressure control valve 75 that controls a value of the back pressure based on a value detected by the second pressure sensor 74, and the second pressure command amplifier 76 that instructs set pressure of the second pressure control valve 75.
According to the configuration, the back pressure of the stopper cylinder device 71 is set to zero based on the stopper rod holding force value generated when the height position of the lower end CF1 of the molding flask CF coincides with the height position of the upper surface MP1 of the pattern surface plate MP. Therefore, the third squeeze unit can be performed with the height positions of the lower end CF1 of the molding flask CF and the upper surface MP1 of the pattern surface plate MP made reliably to be the same.
In addition, a plurality of the stopper cylinder devices 71 of the stopper device 7 is provided corresponding to the stopper rod 72, and each of the stopper cylinder devices 71 is provided with a cut valve 77 that blocks the inflow and outflow of the hydraulic oil to and from each of the stopper cylinder devices 71 at the time of mold release.
According to the configuration, the position of each stopper rod 72 can be maintained horizontally by blocking the inflow and outflow of hydraulic oil to and from the stopper cylinder device 71 at the time of mold release. Therefore, the molding flask CF can be maintained horizontally at the time of mold release, which prevents defects such as chipping of the mold caused by tilting the molding flask CF.
Furthermore, in the casting mold shaping device 1 of the above embodiment, the squeezing table 2 is fixed, and the pressing member 3 is brought close to the squeezing table 2 by the driving mechanism 4, but embodiments of the present invention are not limited thereto. For example, as illustrated in
Although the present invention has been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.
For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-088189 | May 2022 | JP | national |
This application is a national stage of PCT Application No. PCT/JP2023/020357, having a filing date of May 31, 2023, based on Japanese Application No. 2022-088189, having a filing date of May 31, 2022, the entire contents both of which are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/020357 | 5/31/2023 | WO |
