WO2024185786A1

WO2024185786A1 - Mold producing apparatus and mold producing method

Info

Publication number: WO2024185786A1
Application number: PCT/JP2024/008356
Authority: WO
Inventors: 幸一下村
Original assignee: メタルエンジニアリング株式会社
Priority date: 2023-03-07
Filing date: 2024-03-05
Publication date: 2024-09-12

Abstract

Provided are a mold producing apparatus and a mold producing method that allow for a reduction in driving force required to raise a squeeze table, and thus significantly save energy.　This mold producing apparatus produces a mold by compressing molding sand in a flask. The mold producing apparatus comprises: a pressurization execution unit that makes contact with the molding sand; a squeeze table that is opposed to the pressurization execution unit and on which a carrier plate having the flask placed thereon is mounted; and a pressurization drive device that is provided above the pressurization execution unit and compresses the molding sand in the flask by moving the pressurization execution unit toward the squeeze table. The squeeze table includes: a squeeze table lifting device that raises the squeeze table from a standby position to a compression start position located upward of the standby position; and a lowering restriction device that restricts the squeeze table raised to the compression start position from lowering against the pressure exerted by the pressurization drive device during the compression.

Description

Mold making machine and mold making method

　This relates to a molding machine that uses casting sand to make casting molds, and a mold-making method for implementing the molding machine.

As shown in Patent Document 1, a molding sand filling device that fills a molding flask with molding sand and a mold making machine that compresses the molding sand in the flask are described.
The molding sand filling device shown in Patent Document 1 is still in wide use today because it is an excellent method for improving filling properties by allowing the molding sand to fall naturally from directly above the model placed at the bottom of the mold making space.

Patent No. 5596986

However, according to Patent Document 1, when the squeeze table is raised at the molding position (squeezing position), the distance the squeeze table rises is the sum of the amount of rise to the position where the upper end filled with molding sand comes into contact with the pressing part (pressurization part) (molding sand filling position/compression start position) and the amount of rise caused by the subsequent squeeze, and these are raised by a single cylinder. The power of the squeeze cylinder corresponds to the molding sand pressure, but the rise to the aforementioned molding sand filling position requires only the weight of the table and carrier plate, which is significantly smaller than the molding sand pressure. Therefore, excessive driving force is used to raise the molding sand to the position where it comes into contact with the pressing part, and because energy during this period is wasted, further improvements were desired.

The present invention was made in consideration of these conventional problems, and its purpose is to provide a mold making machine and mold making method that can achieve significant energy savings by limiting the driving force required to raise the squeeze table to that required to raise it against the weight of the squeeze table and carrier plate, and by not generating the large driving force required for squeezing.

The first aspect of the present invention is a mold-making machine that compresses the molding sand filled in a flask to make a mold, and includes a pressure application section that contacts the molding sand, a squeeze table that faces the pressure application section and has a carrier plate on which the flask is placed, and a pressure drive device that is located above the pressure application section and compresses the molding sand filled in the flask by moving the pressure application section closer to the squeeze table.

The squeeze table is equipped with a squeeze table lifting device that lifts the squeeze table from a standby position to a compression start position that is higher than the standby position, and a descent restriction device that restricts the descent of the squeeze table against the compression force applied by the compression drive device during compression when the squeeze table has been lifted to the compression start position.

As a result, the squeeze table and carrier plate can be raised to the compression start position with a small driving force, and during compression, which requires a large force, the descent restriction device can counter the pressure applied by the pressure drive device during compression. In this way, the rise to the compression start position can be achieved with a small driving force rather than a large driving force, reducing power waste and reducing running costs.

According to the second aspect of the mold making machine of the present invention, in the first aspect of the mold making machine, the pressurization unit is provided separately from the pressurization drive device and can be moved between a retracted position where it is detached from the pressurization drive device and a squeeze position where it can be pressed by the pressurization drive device to squeeze.

As a result, the pressure application unit, which is the moving part, is separated from the pressure drive device, making it compact, which makes it possible to miniaturize the drive device used for movement and to save space required for movement.

According to the third embodiment of the mold making machine of the present invention, in the first or second embodiment of the mold making machine, the descent restriction device is provided with a support member that is removably mounted below the squeeze table that has risen to the compression start position and restricts the descent of the squeeze table.

This makes it possible to limit the descent of the squeeze table by using a simple structure of a support member installed below the squeeze table to counter the large pressure force acting during squeezing.

According to the fourth aspect of the mold making machine of the present invention, in the third aspect of the mold making machine, the support member is provided with a biasing portion that biases the support member in a direction approaching the squeeze table.

In this way, a gap is created on the lower end side of the support member by the biasing part. Therefore, the support member can be easily fitted under the squeeze table. Then, by compressing the biasing part by applying pressure when squeezing, the gap on the lower end side is eliminated, and tight contact can be easily and reliably achieved.

According to the fifth aspect of the mold making machine of the present invention, in the first aspect of the mold making machine, a pressure transmission part is provided between the pressure implementation part and the pressure drive device, and the pressure transmission part is provided with a retraction device that can be retracted depending on the distance between the pressure implementation part and the pressure drive device or the pressure.

This allows the sand to be pressed at a specified pressure even if there is a change in the squeeze stroke height when the sand pressing is complete. It also absorbs any overload on the pressing drive device that occurs during squeezing.

According to the sixth aspect of the present invention, the mold-making method uses a mold-making machine that includes a pressure application section that is brought into contact with the molding sand, a squeeze table that faces the pressure application section and on which a carrier plate is placed on which a molding flask is stacked, and a pressure drive device that is placed above the pressure application section and that compresses the molding sand filled in the molding flask by moving the pressure application section closer to the squeeze table, and that compresses the molding sand filled in the flask to form a mold.

The system further includes a squeeze table lifting step for lifting the squeeze table from a standby position to a compression start position that is higher than the standby position, and a squeeze table descent restriction step for restricting the descent of the squeeze table, which has been lifted to the compression start position, against the pressure applied by the pressure drive device during compression.

1 is a schematic diagram showing an embodiment of a mold making apparatus using a mold making machine of the present invention, as viewed from the front. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 13 is a diagram showing a state in which the squeeze table is raised to a squeeze start position and the molding sand filling section is positioned at the squeeze position. 4 is a cross-sectional view taken along the line E-E in FIG. 13 is a diagram showing the state in which a support member is fitted under the raised squeeze table and molding sand is poured into the mold forming space. FIG. This is a cross-sectional view taken along the line FF in FIG. 5. 13 is a diagram showing a state in which the pressurizing unit is positioned at a squeeze position. FIG. FIG. 13 is a diagram showing a state in which the pressurization unit is pressurized by driving the pressurization drive device to perform a model surface squeeze and a back squeeze. 13 is a diagram showing a state in which the pressure drive device is raised and the support member is removed from below the squeeze table. FIG. 13 is a diagram showing a state in which the pressurizing unit is raised and the mold is removed. FIG. FIG. 13 shows the squeeze table lowered to disassemble the upper flask, the molding flask, and the lower flask. FIG. 4 is an enlarged cross-sectional view of a portion of the descent restriction device. This is a cross-sectional view taken along the line B-B in FIG. 2 is a cross-sectional view taken along the line CC in FIG. 1. FIG. 15 is a cross-sectional view showing a state in which the support member is fitted under the squeeze table in FIG. 14 . This is a cross-sectional view taken along the line D-D in FIG. FIG. 11 is a schematic front view showing another example of a mold making machine.

(Embodiment)
An embodiment of a mold making apparatus 1 using a mold making machine 5 according to the present invention will be described below with reference to Figs.

As shown in FIG. 1, the mold making device 1 in this embodiment includes a carrier plate replacement device 2, a flask loading device 3, a mold removal device 4, and a mold making machine 5.

1, the direction extending horizontally from left to right is the X direction, and the horizontal direction perpendicular to the X direction is the Y direction. When something is being transported, an imaginary center line along the transport direction is considered, and the side closer to the center line is called the "inside" and the side farther from it is called the "outside."
In addition, in the transportation of the molding flask MF, the starting point side of the transportation is referred to as the upstream side, and the end point side of the transportation is referred to as the downstream side.

(Carrier plate replacement device)
The carrier plate replacement device 2 replaces the upper die carrier plate CU used in the mold making machine 5 with the lower die carrier plate CD.
14, the carrier plate replacing device 2 includes a rotating shaft 21, a shaft support member 22 supported by the rotating shaft 21 so as to be rotatable within a horizontal plane, and arm-shaped two-end holders 23 fixed in parallel and facing relation to both ends of the shaft support member 22. The two-end holders 23 rotate 180 degrees back and forth between a molding position MMP where the mold making machine 5 is located and a transfer position PSP where the carrier plates CU and CD are exchanged (see FIG. 1).

The carrier plate replacement device 2 is a publicly known technology, so a detailed description will be omitted. For example, Japanese Patent No. 6,577,321 describes the carrier plate replacement device 2.

Above the molding position MMP of the carrier plate replacement device 2, a flask loading device 3 and a mold unloading device 4 are provided.

(Flask loading device, mold removal device)
The flask carrying-in device 3 carries the flask MF to be used for molding to just before the carry-in/out position IOP located above the molding position MMP.

The mold removal device 4 removes the molded flask-attached mold MWF from the loading/unloading position IOP downstream to the next process.

The flask loading device 3 and the mold unloading device 4 are roller conveyors and include a support member 31a extending in the Y direction and multiple rollers 31b arranged opposite each other on the inside of the support member 31a. The flasks MF that are loaded and transported are lined up and transported, for example, by a pusher device and a cushion device (not shown).

The flask MF that is brought into the loading/unloading position IOP is handed over to the mold making machine 5.

(Mold making machine)
The mold making machine 5 overlaps the flask MF, the lower flask ULF, and the upper flask OLF on the carrier plates CU and CD to form the overlapping flask PMF (see FIG. 3), and squeezes the molding sand CS poured into the overlapping flask PMF to compact the molding sand CS and form a mold with flask MWF (see FIG. 11).

As shown in FIG. 1, the mold making machine 5 is equipped with a pressure application section 51, a pressure application section lifting device 52 (see FIG. 2), a squeeze table 53, a squeeze table lifting device 54, a descent restriction device 55, a pressure application drive device 59, and a pressure application section/casting sand filling section switching device 58.

(Pressurization section)
As shown in FIG. 1 , the pressurizing unit 51 includes a squeeze foot 511 and a lifting frame 512 .
The squeeze foot 511 has a substantially cubic abutment portion 511a and a bar-shaped rod portion. The abutment portions 511a are arranged in a rectangular shape when viewed from below, and the lower surface of the abutment portions 511a pressurizes the casting sand CS.

The lifting frame 512 is, for example, made of iron and formed into a three-dimensional rectangular shape, and inside the lifting frame 512, multiple cylinder sections 512a are arranged in a rectangular shape in a plan view.

Each cylinder section 512a is provided corresponding to a respective squeeze foot 511, and the upper end of the rod portion of the squeeze foot 511 is a piston. The multiple cylinder sections 512a are connected by a first oil passage FP1, so that hydraulic force acts evenly in all cylinder sections 512a. The cylinder sections 512a are connected to the hydraulic pump HP via the first oil passage FP1, and a first solenoid switching valve SSV1 is provided between the cylinder sections 512a and the hydraulic pump HP.

The cylinder section 512a is filled with hydraulic oil above the piston. When the squeeze foot 511 compresses the casting sand CS at its lower end, the pressure applied is determined by the hydraulic pressure in the cylinder section 512a (i.e., the back pressure acting on the piston). These multiple cylinder sections 512a are connected to a single hydraulic pump HP via a first oil passage FP1.

A first pressure sensor PS1 is provided between the cylinder section 512a and the first solenoid switching valve SSV1. The first pressure sensor PS1 detects the pressure on the back pressure side of the cylinder section 512a. A branch oil passage connected to a first pressure control valve PC1 is provided between the first pressure sensor PS1 and the hydraulic pump HP. The first pressure control valve PC1 acts as a pressure reducing valve that reduces pressure based on a specified pressure value commanded by the connected pressure command amplifier PCA. The operation of the first solenoid switching valve SSV1 is controlled by a control device (not shown).

(Pressurization section lifting device)
The pressurization section lifting device 52 raises and lowers the height position of the pressurization section 51 between a foundry sand approaching position and a holding position (not shown).
The molding sand approaching position is, for example, a position where the contacting part 511a can be brought close to just before it contacts the upper end surface of the molding sand CS poured into the mold forming space US. The holding position is a position above the molding sand approaching position, for example, a position where the pressurizing part 51 is held when it is moved laterally by a pressurizing part/molding sand filling part switching device 58 described later.

Since the pressurization unit lifting device 52 only moves the pressurization unit 51 up and down, the force it is subjected to is only the weight of the pressurization unit 51. As such, it does not require a large driving force such as that used for squeezing, so a small, inexpensive driving device is sufficient, and running costs can be reduced.

As shown in FIG. 2, the pressurizing section lifting device 52 includes a support frame 521, a lifting cylinder device 522, and a guide support rod 523 (see FIG. 1).
The support frame 521 is provided above a moving base 581 of the pressurizing unit/casting sand filling unit switching device 58, which will be described later. The support frame 521 is, for example, made of iron and formed into a rectangular frame shape with an opening on the inside. The pressurizing unit 51 is supported by the moving base 581 via the support frame 521.

A tip of a support rod 522a of a lift cylinder device 522 is connected to the underside of the center part of the support frame 521, which is a side extending in the X direction. A lift cylinder part 522b of the lift cylinder device 522 is attached to the moving base 581 in a state where it penetrates the moving base 581.
Each of the lift cylinders 522b is connected to a hydraulic pump via an oil supply pipe (not shown). An electromagnetic switching valve (not shown) is provided between the lift cylinders 522b and the hydraulic pump, and the operation of the electromagnetic switching valve is controlled by a control device (not shown).

The upper ends of guide support rods 523 are connected to the lower surface of the center portion of the support frame 521, which is a side extending in the Y direction.
The guide support rod 523 has a lower end connected to the upper surface of the lift frame 512 , and a lower portion of the middle portion slidably inserted into a support cylinder portion 523 a provided on the moving base 581 .

(Squeeze table)
The squeeze table 53, on which the carrier plates CU and CD to which the model CM and model surface plate MSP are fixed, faces the pressurizing unit 51 and receives the pressing force during squeezing. The carrier plates CU and CD, the molding flask MF, the lower filling flask ULF, and the upper filling flask OLF are superimposed on the squeeze table 53 to form the overlapping flask PMF (see FIG. 3). Molding sand CS is then poured into the formed overlapping flask PMF, and the squeeze table 53 and the pressurizing unit 51 are brought relatively close to each other to perform squeezing.

As shown in FIG. 2, the squeeze table 53 includes a squeeze table body 531 and a table support portion 532. The squeeze table body 531 is made of iron, for example, and is formed in the shape of a rectangular thick plate.

As shown in Fig. 1, lower hydraulic cylinders 533 are disposed at the four corners of squeeze table body 531. Lower hydraulic cylinder 533 has a bottom and a guide hole at the top. A shaft member 533a having a flange (piston) at the bottom is inserted into the guide hole so as to be movable up and down. When shaft member 533a is retracted to the lowest end of lower hydraulic cylinder 533, the tip position of shaft member 533a coincides with the upper surface of squeeze table body 531.
The shaft member 533a abuts against a support rod member UFM of the lower filling frame ULF described later, thereby raising the upper end of the lower filling frame ULF above the height of the upper surface of the model surface plate MSP, thereby ensuring a squeeze allowance at the bottom.

The lower hydraulic cylinder 533 is connected at its upper and lower ends to a hydraulic pump (not shown).
The lower hydraulic cylinder 533 and the hydraulic circuit are well-known technologies, and therefore detailed description thereof will be omitted. These technologies are described, for example, in Japanese Patent Publication No. 5995542.

The table support part 532 is made of, for example, iron and is formed into a cylindrical shape extending along the vertical direction. The table support part 532 is connected to the center of the bottom of the squeeze table main body 531. A support base part 534 is provided opposite the lower end of the table support part 532.

The support base portion 534 is made of iron, for example, in the shape of a short cylinder, and is fixed to the base BS.
When the squeeze table 53 is positioned at the upper end (compression start position CSP) (see FIG. 4), a support member 551 of the descent restriction device 55 described later is removably fitted between the lower end of the table support portion 532 and the upper end of the support base portion 534 (see FIG. 5).

(Squeeze table lifting device)
As shown in FIG. 4, the squeeze table lifting device 54 lifts and lowers the squeeze table 53 between a standby position SBP at the lower end and a compression start position CSP above the standby position SBP.

When the squeeze table 53 rises, the flask MF and upper flask OLF are stacked in order on the lower flask ULF provided on the carrier plates CU and CD to form the overlapping flask PMF, forming the mold forming space US (see Figure 3).

As shown in FIGS. 1 and 2, the squeeze table lifting device 54 includes a hydraulic cylinder device 541 and a guide device 542.
The hydraulic cylinder devices 541 are provided in a pair lined up along the Y direction with the table support portion 532 in between. The hydraulic cylinder devices 541 are erected so as to extend along the vertical direction, and include a hydraulic cylinder portion 541a and a piston portion 541b (see FIG. 4).

The hydraulic cylinder section 541a is made of iron, for example, and is formed into a rectangular cylinder with a bottom. The hydraulic cylinder sections 541a are provided in pairs, sandwiching the table support section 532. The lower ends of the paired hydraulic cylinder sections 541a are fixed to the base BS, and the rods of the piston sections 541b move up and down from the openings at the upper ends. The tips of the rods of the piston sections 541b are each connected to the bottom of the squeeze table 53.

The hydraulic cylinder section 541a is connected to a hydraulic pump (not shown) via an oil supply pipe (not shown). An electromagnetic switching valve (not shown) is provided between the hydraulic cylinder section 541a and the hydraulic pump. The operation of the electromagnetic switching valve is controlled by a control device (not shown).

The guide devices 542 are arranged side by side in the X direction, with two hydraulic cylinder devices 541 between each of them, for a total of four guide devices 542 (see FIG. 14).
The guide device 542 guides the squeeze table 53 so that the lifting and lowering of the squeeze table 53 is performed in the vertical direction.
The guide device 542 includes a cylindrical portion 542a and a guide rod portion 542b. The lower end of the cylindrical portion 542a is fixed to the upper surface of the base BS. The guide rod portion 542b is slidably fitted into the cylindrical portion 542a, and the tip portion is connected to the bottom of the squeeze table main body 531.

(Support member)
The support member 551 is fitted between the lower end of the table support part 532 and the upper end of the support base part 534 installed on the base BS, thereby restricting the descent of the squeeze table 53 (descent restriction device 55). This makes it possible to counter the pressure force applied by the pressure drive device 59, and it is not necessary to generate a large drive force for the squeeze table lifting device 54 that lifts and lowers the squeeze table 53.
Therefore, the running costs can be significantly reduced.

As shown in FIGS. 12 and 14, the support member 551 includes a support member main body 551 a , a cylindrical guide portion 551 b , a coil spring 551 c serving as a biasing portion, and a slide mechanism 552 .
The support member main body 551a is, for example, made of iron and formed into a cylindrical shape, with a flange portion 551f provided around the outer periphery at a height position about one third of the total length from the bottom end.

As shown in FIG. 14, the cylindrical guide portion 551b is made of iron, for example, and formed into a square tube. The support member main body 551a is slidably fitted into the through hole of the cylindrical guide portion 551b. As shown in FIG. 12, the inner lower portion of the cylindrical guide portion 551b is formed with a large diameter of the inner wall, and a flange portion 551f and a coil spring 551c, which will be described later, are fitted into it.

The lower end of the cylindrical guide portion 551b has a through hole with the same diameter as the upper portion, and a compressed coil spring 551c is sandwiched between the bottom wall 551w and the flange portion 551f on the inner periphery of the through hole. The support member main body 551a is biased toward the squeeze table 53 (upward) by the coil spring 551c.

The support member body 551a rises a predetermined length due to the biasing force of the coil spring 551c, and this raised distance creates a gap between the bottom end of the support member body 551a and the top end of the support base portion 534.

(Slide mechanism)
13 and 14, the slide mechanism 552 includes a connecting portion 552a, a slide rod 552b, a moving rail 552c, a rolling wheel 552d, a crank arm 552e, and a groove portion 552f. The slide mechanism 552 forms a cross slider crank mechanism in which the axes of two sliding pairs intersect at a right angle.

The connecting portion 552a connects the cylindrical guide portion 551b and the slide rod 552b. The connecting portion 552a is formed in a U-shape in a plan view, and the two ends of the U-shape are connected to the lower portion of the cylindrical guide portion 551b on the opposite side of the rotation shaft 21 of the carrier plate replacement device 2. One end of the slide rod 552b (described later) is connected to the surface of the connecting portion 552a extending in the Y direction.

The slide rod 552b is formed, for example, from a long iron plate extending in the X direction. The slide rod 552b has a rectangular cross section with its long sides extending vertically.

As shown in FIG. 13, a pair of rolling wheels 552d having a rotation axis extending outward in the Y direction are provided at the bottom of the cylindrical guide portion 551b. The rolling wheels 552d move in the X direction on a pair of moving rails 552c fixed to a structure not shown.

The slide rod 552b is also provided with at least a pair of rolling wheels (not shown), and similarly moves along the X direction on the moving rail 552c.

A groove 552f is provided at the other end of the slide rod 552b. The groove 552f has two guide rails 552g that are aligned parallel to the X direction and extend vertically.

A guide roller 552r is fitted into the groove 552f, and the guide roller 552r is provided at the tip of a crank arm 552e that is rotated by an electric motor 553.

When the crank arm 552e rotates, the guide roller moves up and down relative to the groove 552f, and the slide rod 552b moves back and forth linearly along the X direction.

As shown in Figures 14 and 15, the slide mechanism 552 causes the support member main body 551a to reciprocate between a support position SP, where it is fitted between the table support part 532 and the support base part 534, and a support preparation position SRP, where it is removed from the support position SP. When positioned in the support preparation position SRP, a part of the lower part of the table support part 532 can be inserted into the U-shaped space of the connecting part 552a.

(Upper frame holding part)
The upper filling frame holding portion 56 holds the upper filling frame OLF above the load-in/load-out position IOP and the molding position MMP.
As shown in FIG. 1 , the upper filling frame holding portion 56 includes a locking portion 561 , a locking rod 562 , and a locking spring 563 .

The locking portions 561 are provided in pairs aligned in the X direction on the inside of the four support columns of the structure. The locking portions 561 are formed by a plate material of a predetermined length protruding inward. Each of the locking portions 561 has a locking hole penetrating in the vertical direction.
A locking rod 562, which will be described later, is slidably inserted into each locking hole.

The locking rod 562 is, for example, made of iron and formed into a rod shape. As shown in FIG. 3, the locking rod 562 has an upper flange 562a at its upper end and a lower flange 562b at its lower end. For example, a nut that is fastened to a male thread formed on the locking rod 562 can be used as the lower flange 562b.

A locking spring (coil spring) 563 is provided between the lower flange 562b and the sliding support part OLF2 of the upper filling frame OLF, which will be described later. When the upper filling frame OLF is at a height position higher than a predetermined position, the locking rod 562 slides through the locking hole of the locking part 561 and moves upward. When the upper filling frame OLF is at a height position lower than the predetermined position, the locking spring 563 generates an upward biasing force on the upper filling frame OLF.

(Upper frame)
The upper flask OLF is placed on top of the flask MF to ensure a squeeze allowance when squeezing the model CM from the back side. Note that "squeezing from the back side of the model (back squeeze)" refers to squeezing the molding sand CS from above, which has been poured into the mold forming space US with the model CM located below.
As shown in Figures 1 and 3, the upper filling frame OLF of this embodiment comprises an upper filling frame main body OLF1, a sliding support part OLF2, an upper abutment part OLF3, a lower abutment part OLF4, and a guide wall OLF5.

The upper filling frame main body OLF1 is made of iron, for example, and is formed in the shape of a short rectangular frame.
The sliding support part OLF2 forms a flange part that protrudes from the upper end of the upper filling frame main body OLF1 to the outer periphery, and a through support hole OLF6 is formed at the end in the X direction. The through support hole OLF6 is formed by raising the periphery of the hole upward.

The aforementioned locking rod 562 is slidably inserted through the through support hole OLF6. The aforementioned locking spring (coil spring) 563 is fitted between the lower flange 562b of the locking rod 562 and the outer circumferential underside of the through support hole OLF6 of the sliding support part OLF2.

As shown in FIG. 1, upper contact portions OLF3 are protrudingly provided at the four corners of the upper surface of the sliding support portion OLF2 at positions facing the four corners of the lower surface of the lift-up frame 512.
Lower contact members OLF4 protrude from the four corners of the lower surface of the sliding support member OLF2 at positions facing the upper surface of the four corners of the molding flask MF.

The guide wall OLF5 fits around the lower ends of the hopper 571 in the casting sand filling section 57, which are aligned in the X direction, to prevent the casting sand CS being added from spilling out and falling.

The guide walls OLF5 are formed in pairs at a predetermined height in the vertical direction on both sides of the upper end of the upper filling frame body OLF1 extending in the Y direction. The length of the guide walls OLF5 in the Y direction is set to the same length as the end of the sliding support part OLF2, as shown in Figure 2. They are connected to a casting sand receiving chute 572, which will be described later.
The lower filling frame ULF will also be explained next.

(Lower frame)
The lower filling frame ULF secures a squeeze allowance for the squeeze performed from the model surface side. Note that "squeezing performed from the model surface side (model surface squeeze)" refers to a squeeze in which pressure is applied relatively upward from below, where the model CM is located, to the molding sand CS poured into the mold forming space US.
The lower filling frame ULF is made of, for example, iron and formed into a rectangular frame, and is provided on the upper outer periphery of the carrier plates CU and CD so as to be movable relative to each other in the vertical direction. Support rod members UFM are provided at the four corners of the lower filling frame ULF so as to protrude downward. Each support rod member UFM faces a shaft member 533a provided on the squeeze table 53.

When the lowering frame ULF is at the lower end relative to the carrier plates CU and CD, its upper end is flush with the top surface of the model surface plate MSP. The support rod member UFM comes into contact with the shaft member 533a and is pushed up, moving the upper end of the lowering frame ULF to a position higher than the top surface of the model surface plate MSP, ensuring a squeeze allowance.

(Casting sand filling section)
As shown in Figures 2 and 3, the foundry sand filling section 57 stores the amount of foundry sand CS required for molding a mold to be produced at one time as one unit, and is equipped with a hopper 571 that abuts against the upper surface of the upper filling frame OLF and deposits the foundry sand CS into the mold molding space US.

The hopper 571 has a chute that contacts the upper surface of the upper filling frame OLF, and is provided with a plurality of gate plates 571b that divide the inside of the hopper 571 into upper and lower parts. The upper part of the gate plates 571b is a sand measuring section that stores the casting sand CS.
In the sand measuring section, molding sand CS is transported by a conveyor device (not shown) and stored therein.

The gate plates 571b are, for example, made of iron and formed into a flat plate, with multiple gate plates 571b arranged adjacent to one another. Each gate plate 571b is attached to a horizontal shaft passing through the center, and the horizontal shafts are arranged parallel to one another in an imaginary plane. Each gate plate 571b is rotated around the horizontal shaft by a rotating device (not shown).

When the gate plate 571b is positioned in a horizontal position, the inside of the hopper 571 is divided into upper and lower sections, allowing the casting sand CS to be stored. When the gate plate 571b is rotated and positioned in a vertical position, the stored casting sand CS falls naturally into the mold forming space US (see Figure 5).

In addition, when the lower end of the hopper 571 moves to switch to the pressurization section 51 after the casting sand CS has been poured into the mold forming space US, the excess part of the casting sand CS that has risen above the upper filling frame OLF is scraped off and dropped into the casting sand receiving chute 572. The casting sand CS that has fallen into the casting sand receiving chute 572 is transported by a conveyor (not shown) and reused.

(Pressure application section/casting sand filling section switching device)
The pressurization unit/molding sand filling unit switching device 58 moves either the pressurization unit 51 or the molding sand filling unit 57 so as to position it at the squeeze position PP.

The pressurization/casting sand filling switching device 58 includes a moving base 581 (see FIG. 2), a roller conveyor 582 (see FIG. 1), side rollers 583 (see FIG. 1), a guide groove 584, a crank arm 585, and an electric motor 586 (see FIG. 16).

The movable base 581 is made of iron, for example, and is formed into a rectangular frame shape that is long in the Y direction. As shown in FIG. 2, the pressurization unit 51 is attached to the left side of the movable base 581, and the casting sand filling unit 57 is attached to the right side. As shown in FIG. 1, protrusions 581b are formed on the lower part of both ends of the movable base 581 in the X direction, and the protrusions 581b extend along the Y direction. These protrusions 581b are placed on the roller conveyor 582, which will be described later.

As mentioned above, the lifting cylinder portion 522b of the pressurizing section lifting device 52 is assembled in a state where it penetrates the moving base 581 (see Figure 2).

As shown in FIG. 1, the roller conveyor 582 includes a roller support member 582a extending along the Y direction, and a plurality of rollers 582b.
The roller support member 582a is made of, for example, iron, is formed in a strip shape with a rectangular cross section, and is fixed to a support column of the structure so as to extend along the Y-axis direction. The rollers 582b are each formed in a disk shape and are rotatably mounted on a rotation shaft that protrudes along the X-axis direction inside the paired roller support member 582a.

The side rollers 583 are arranged in pairs above the roller support member 582a, sandwiching the moving base 581 from both sides in the X direction. Multiple pairs of side rollers 583 are arranged side by side in the Y direction. Each side roller 583 is rotatably supported on a rotating shaft extending in the vertical direction provided on the structure. The side rollers 583 roll in contact with the outer surface of the moving base 581 extending along the Y direction, allowing the moving base 581 to move smoothly.

The guide groove 584 is provided at the end of the movable base 581 on the casting sand filling section 57 side, and at the right end in FIG. 1. As shown in FIG. 2, the guide groove 584 is equipped with a guide post 584a and a pair of guide strips 584b that are erected vertically on the movable base 581. A guide roller 585a provided at the tip of a crank arm 585 (described later) is fitted into the guide groove 584 so as to be able to roll.

The crank arm 585 has a base end connected to the output shaft of an electric motor 586 (see FIG. 16) that is fixed to a structure not shown, and the crank arm 585 rotates when driven by the electric motor 586. The electric motor 586 can rotate forward and backward, and the rotation of the electric motor 586 is controlled by a control device not shown.

The pressurization unit/casting sand filling unit switching device 58 constitutes a cross slider mechanism, and the moving base 581 moves with the rotation of the crank arm 585. This switches either the pressurization unit 51 or the casting sand filling unit 57 to face the squeeze position PP.

(Pressure drive device)
The pressure drive device 59 applies pressure to the pressure application section 51 from above toward the squeeze table 53, thereby squeezing the casting sand CS that has been poured into the mold forming space US.
The pressure drive device 59 includes a swing arm 591 , a drive small gear 592 , a link member 593 , and a slider member 594 .

The swing arm 591 has an arc portion 591a, a pin gear 591b arranged along the arc portion 591a, and an arm portion 591c whose base end is supported by a rotating shaft on the structure and which is continuous with one end of the arc portion 591a. The swing arm 591 is formed by two plates of the same shape facing each other, and the pin gears 591b are provided on the outside of each of the two plates.

The arc portion 591a is formed, for example, by a circumferential portion that corresponds to approximately 50 degrees of a circle whose radius is the arm portion 591c. A driving small gear 592 that is connected to the output shaft of an electric motor 595 meshes with the pin gear 591b.

The electric motor 595 is, for example, a servo-controlled motor. The electric motor 595 is mounted on a support pillar SS erected on the upper surface of the top part TP of the structure, with the motor rotation shaft extending along the X direction. The driving pinion 592 is mounted so that the rotation shaft extends along the Y direction via a reduction gear (not shown).

A connecting shaft 591e is provided near the rotation shaft 591d of the arm portion 591c, and one end of the link member 593 is rotatably connected to the connecting shaft 591e. The other end of the link member 593 is connected to the slider member 594 via the connecting shaft 593e.

The slider member 594 is inserted into a slot GV formed in the top portion TP. The slider member 594 includes a slider body 594a having a rectangular cylindrical shape with a bottom, and a short cylindrical abutment body 594b provided on the underside of the bottom portion of the slider body 594a.
Rollers 594c are provided vertically side by side on both ends in the X direction of the slider body 594a.

The slot GV is formed in a rectangular shape, and a guide plate GV1 is provided on the inner wall facing the X direction so as to extend in the vertical direction. The roller 594c of the slider body 594a contacts and rolls on the inner wall of the guide plate GV1, guiding the slider body 594a to move up and down.
The abutment body 594b abuts against the upper end of the retraction device 60, which will be described later.

(Retraction device)
The retraction device 60 is provided between the pressurizing section 51 and the pressurizing drive device 59, and can apply a predetermined pressure required for squeezing even if a slight variation occurs in the squeeze stroke height when the pressing of the molding sand is completed. It can also absorb an overload on the electric motor 595 that may occur during squeezing.

The retraction device 60 comprises an abutment column 602 and a retraction cylinder portion 601. The abutment column 602 is made of iron, for example, and formed into a cylindrical shape, and a flange portion equivalent to a piston is provided at the lower end. The abutment column 602 corresponds to the pressure force transmission portion.

The retraction cylinder section 601 is provided in the center of the upper end of the lifting frame 512, and the lower part of the abutment column 602 is fitted into the opening at the upper end so that it can move forward and backward. The retraction cylinder section 601 is connected to the hydraulic pump HP via the second oil passage FP2.

A second pressure sensor PS2, a second solenoid switching valve SSV2, and a check valve NRV are provided between the retraction cylinder section 601 and the hydraulic pump HP. A branch line leading to the relief valve RV is provided in the second oil passage FP2 between the second pressure sensor PS2 and the second solenoid switching valve SSV2. The back pressure inside the retraction cylinder section 601 is detected by the second pressure sensor PS2, and the relief valve RV reduces the overload that occurs during squeezing.

(Control device)
The control device (not shown) mainly controls the operation of the following devices.
Electric motor 586 of pressurization implementation section/casting sand filling section switching device 58, rotation of gate plate 571b of casting sand filling section 57, lifting and lowering by hydraulic cylinder device 541 of squeeze table lifting device 54, electric motor 553 in slide mechanism 552 of descent restriction device 55, electric motor 595 in drive pinion 592 of pressurization drive device 59, switching of first solenoid switching valve SSV1 of pressurization implementation section 51, switching of second solenoid switching valve SSV2 of retraction device 60, etc.

(Operation)
The operation of the mold making apparatus 1 configured as above will be described below with reference to FIGS. 1 to 11 and 14 to 16.
1, an upper mold carrier plate CU is positioned at a molding position MMP. The squeeze table is positioned at a standby position SBP (see FIG. 2) which is the lower end.

Above the upper mold carrier plate CU, a molding flask MF is positioned at an insertion/removal position IOP, as shown in Fig. 2. Above the molding flask MF, a top filling flask OLF is held.
A molding sand filling section 57 is positioned above the upper filling frame OLF, and a single load of molding sand CS is stored in the upper part of a hopper 571.
The pressurizing unit 51 is held at the upper end of the contact body 594 b of the slider member 594 , and is located above the hopper 571 .

Next, the control device drives the hydraulic cylinder device 541 of the squeeze table lifting device 54 to lift the squeeze table 53 from the standby position SBP to the compression start position CSP (squeeze table lifting process; see Figure 4).

The control device also switches the electromagnetic switching valve (not shown) to increase the oil pressure in the lower hydraulic cylinder 533 of the squeeze table 53, lifting the shaft member 533a. The shaft member 533a is then brought into contact with the lower end of the support rod member UFM of the lower filling frame ULF. The upper end ULFT of the lower filling frame ULF rises above the upper end surface MSPT of the model surface plate MSP, creating a squeeze allowance (see Figure 4).

As a result, the lower flask ULF, the flask MF, and the upper flask OLF are stacked to form the overlapping flask PMF, which, together with the model platen MSP, forms the mold making space US (see Figure 3).

Next, the control device drives the slide mechanism 552 of the descent restriction device 55 to move the support member 551 from the support preparation position SRP to the support position SP (see Figures 14 and 15). As a result, the support member 551 is positioned between the lower end of the table support portion 532 and the upper end of the support base portion 534 (squeeze table descent restriction process; see Figures 5 and 6).

At this time, the support member 551 is biased upward by the coil spring 551c and moved so as to form a lower gap between it and the support base 534. Therefore, when fitting, it is sufficient to leave an upper gap between the upper end of the support member 551 and the lower end of the table support 532 and fit the support member 551. After fitting, simply by lowering the squeeze table 53, the support member 551 can easily support the applied force in a state of close contact with the lower end of the table support 532 and the upper end of the support base 534 with no gap between them.

The control device also rotates the gate plate 571b of the casting sand filling section 57 by 90 degrees, as shown in FIG. 5, to allow the stored casting sand CS to fall into the mold forming space US.

Then, as shown in FIG. 7, the control device drives the pressurization unit/casting sand filling unit switching device 58 to position the pressurization unit 51 from the retracted position RTP to the squeeze position PP facing the squeeze table 53 (see FIG. 2). The control device drives the squeeze table lifting device 54 to lower the squeeze table 53 so as to eliminate the gap, and to bring the support member 551 into close contact with the table support unit 532 and the support base unit 534.

Next, the control device drives the electric motor 595 of the pressure drive device 59 to rotate the swing arm 591 to the opposite end, as shown in Fig. 8. This applies pressure to the pressure application section 51, and squeezes the molding sand CS in the mold forming space US.
A retraction device 60 is provided between the pressure drive device 59 and the pressure implementation unit 51. Therefore, even if there is a variation in the squeeze stroke height when the molding sand CS is completely pressed, the molding sand CS can be pressed at a predetermined pressure. In addition, the overload on the pressure drive device 59 that occurs during squeezing can be absorbed.

The squeeze involves a so-called double squeeze, in which both a model surface squeeze is performed from below the model surface, and a back squeeze is performed from the back of the model surface.

In the model surface squeeze, when the pressurizing unit 51 pressurizes the upper surface of the casting sand CS, the pressure inside the lower hydraulic cylinder 533 of the squeeze table 53 is reduced, allowing the shaft member 533a to move backward. Then, the lifting frame 512 of the pressurizing unit 51 is brought into contact with the upper contact part OLF3 of the upper filling frame OLF, causing the overlapping frame PMF to slide downward relative to the model base plate MSP. The amount of sliding is the squeeze allowance formed by the lower filling frame ULF. Then, when the height positions of the lower end of the flask MF and the upper surface of the model base plate MSP are aligned, the sliding of the overlapping frame PMF is stopped. In this way, the model surface squeeze is achieved, in which the casting sand MS is pressurized from the model surface side.

In the rear squeeze, the upper surface of the casting sand CS is further pressed by the squeeze feet 511 of the pressurizing unit 51. Each squeeze foot 511 applies pressure with the same pressure, but the amount of penetration into the casting sand CS varies depending on the shape of the pattern, etc., so that the casting sand CS can be squeezed evenly.
Since the double squeeze, which performs both the model face squeeze and the back squeeze in this manner, is a known technique, a detailed description thereof will be omitted.

Next, as shown in FIG. 9, the control device drives the pressure drive device 59 in the backward direction to move the slider member 594 upward.
Then, the slide mechanism 552 of the descent restriction device 55 is driven to move the support member 551 from the support position SP to the support preparation position SRP.

Next, the control device drives squeeze table lifting device 54 to lower squeeze table 53, as shown in FIG.
As the squeeze table 53 descends, the overlapping upper flask OLF, flask MF and lower flask ULF are removed in order.
Next, as shown in FIG. 11, the control device lowers the squeeze table 53 to the standby position SBP, and also retracts the swing arm 591 of the pressure drive device 59 to its initial position before pressure is applied.
The removed flask mold MWF is then removed from the carry-in/out position IOP.
The same process is repeated below.

As is clear from the above description, the mold making machine 5 of this embodiment is a mold making machine 5 that compresses the foundry sand CS filled in the flask MF to make the mold MWF, and is equipped with a pressure implementing unit 51 that contacts the foundry sand CS, a squeeze table 53 that faces the pressure implementing unit 51 and is equipped with carrier plates CU and CD on which the flask MF is stacked, and a pressure driving device 59 that is installed above the pressure implementing unit 51 and compresses the foundry sand CS filled in the flask MF by moving the pressure implementing unit 51 close to the squeeze table 53.

The squeeze table 53 is equipped with a squeeze table lifting device 54 that lifts the squeeze table 53 from the standby position SBP to the compression start position CSP, which is higher than the standby position SBP, and a descent restriction device 55 that restricts the descent of the squeeze table 53 against the compression force applied by the pressure drive device 59 during compression when the squeeze table 53 has been lifted to the compression start position CSP.

As a result, the squeeze table 53 and carrier plates CU and CD can be raised to the compression start position CSP with a small driving force, and during compression, which requires a large force, the descent restriction device 55 can counter the pressure applied by the pressure drive device 59 during compression. In this way, the rise to the compression start position CSP can be achieved with a small driving force rather than a large driving force, reducing power waste and reducing running costs.

The pressurization unit 51 is provided separately from the pressurization drive device 59 and can move between a retracted position RTP where it is removed from the pressurization drive device 59 and a squeeze position PP where it can be squeezed by applying pressure with the pressurization drive device.

As a result, the pressure application unit 51, which is the moving part, is separated from the pressure drive device 59, making it compact, which makes it possible to miniaturize the drive device used for movement and to save space required for movement.

The descent restriction device 55 also includes a support member 551 that is removably fitted below the squeeze table 53 that has risen to the compression start position CSP and restricts the descent of the squeeze table 53.

As a result, the simple structure of the support member 551 provided below the squeeze table 53 can resist the large pressure force acting during squeezing and regulate the descent of the squeeze table 53.

The support member 551 is also provided with a coil spring 551c (biasing portion) that biases the support member 551 in a direction approaching the squeeze table 53.

As a result, a gap is created at the lower end of the support member 551 by the coil spring 551c. Therefore, the support member 551 can be easily fitted under the squeeze table 53. Then, by compressing the coil spring 551c by applying pressure during squeezing, the gap at the lower end is eliminated, and the support member 551 can be easily and reliably brought into close contact.

In addition, a contact column 602 (pressure transmission section) is provided between the pressurizing section 51 and the pressurizing drive device 59, and the contact column 602 is provided with a retractable cylinder section 601 that can be retracted depending on the distance between the pressurizing section 51 and the pressurizing drive device 59 or the pressurizing force.

This allows the molding sand CS to be pressed at a specified pressure even if there is a variation in the squeeze stroke height when pressing the molding sand CS is complete. It also makes it possible to absorb overload on the pressurizing drive device that occurs during squeezing.

In the above embodiment, the retraction device 60 is provided between the pressure drive device 59 and the pressure implementation unit 51, but this is not limited to the above. For example, as shown in FIG. 17, the retraction device 160 may be provided on the lifting frame 152 of the pressure implementation unit 151, and retracted at a position where the upper filling frame OLF is pressurized.

In this example of the retraction device 160, hydraulic retraction cylinders 1601 are provided at the four corners of the lifting frame 1512, and the abutment columns 1602 abut against the upper abutment parts OLF3 of the upper filling frame OLF. This prevents overloading of the electric motor during squeezing, and allows pressure to be applied at a specified pressure even if fluctuations occur in height.

In addition, in the above embodiment, both the model surface squeeze performed from the model surface upward and the back squeeze performed from above the model surface downward are performed, but this is not limited to this. For example, the descent restriction device 55 can also be used in a mold making machine that only performs a back squeeze.

The present invention is not limited to the embodiments described above and shown in the drawings, and can be modified as appropriate without departing from the spirit and scope of the invention.

5: Mold making machine, 51: Pressurization unit, 53: Squeeze table, 54: Squeeze table lifting device, 55: Descent restriction device, 551: Support member, 551c: Coil spring (biasing unit), 59: Pressurization drive unit, 60: Retraction device, 601: Retraction cylinder (retraction device), 602: Pressurization force transmission unit, CS: Casting sand, CSP: Compression start position, MF: Molding flask, MSP: Model surface plate, MWF: Flask mold, PP: Squeeze position, RTP: Retract position, SBP: Standby position, CU: Carrier plate for upper die, CD: Carrier plate for lower die, CU/CD: Carrier plates.

Claims

A mold making machine that compresses molding sand filled in a flask to make a mold,
a pressurizing portion that contacts the molding sand;
a squeeze table provided opposite the pressurizing unit and on which a carrier plate on which the molding flask is placed is mounted;
a pressurizing drive device that is provided above the pressurizing unit and that compresses the molding sand filled in the molding flask by moving the pressurizing unit closer to the squeeze table,
The squeeze table includes:
A squeeze table lifting device that lifts the squeeze table from a standby position to a compression start position that is higher than the standby position;
a descent restriction device that restricts descent of the squeeze table raised to the compression start position against a pressing force applied by the pressurizing drive device when compressing the molding sand;
A mold making machine equipped with
The mold making machine according to claim 1, wherein the pressurizing unit is provided separately from the pressurizing drive device and is movable between a retracted position where it is detached from the pressurizing drive device and a squeeze position where it is pressurized by the pressurizing drive device to squeeze.
The mold making machine according to claim 1 or 2, wherein the descent restriction device is provided with a support member that is removably attached below the squeeze table that has risen to the compression start position and restricts the descent of the squeeze table.
The mold making machine according to claim 3, wherein the support member is provided with a biasing portion that biases the support member in a direction approaching the squeeze table.
a pressure transmission unit is provided between the pressure implementation unit and the pressure drive device,
2. The mold making machine according to claim 1, wherein the pressure transmission section is provided with a retraction device that can be retracted depending on the distance between the pressure implementation section and the pressure drive device or the pressure.
a pressurizing unit that is brought into contact with the casting sand;
a squeeze table provided opposite the pressurizing unit and on which a carrier plate on which a molding flask is stacked is disposed;
a pressurizing drive device that is provided above the pressurizing unit and that compresses the molding sand filled in the molding flask by moving the pressurizing unit closer to the squeeze table,
A mold-making method using a mold-making machine that compresses the molding sand filled in the flask to make a mold, comprising the steps of:
a squeeze table lifting step of lifting the squeeze table from a standby position to a compression start position that is higher than the standby position;
a squeeze table descent regulating step of regulating descent of the squeeze table raised to the compression start position against a pressing force applied by the pressurizing drive device when compressing the molding sand;
A mold making method comprising the steps of: