JPH0527504B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a green sand core molding device, and more specifically, it is capable of molding a green sand core in which the central portion is thicker than the peripheral portion. Regarding equipment.

(Prior art) Mainly for reasons of strength and dimensional accuracy, cores are produced using the shell mold method, cold box method,
It is customary to mold using CO ₂ method etc.
Cores made in this way are expensive and have different properties from the main mold made of raw sand.
There is a problem with the sand recycling process after pouring. For this reason, various methods of molding cores using the same green sand as the main mold have recently been attempted, and cores of relatively simple shapes that can be used for practical purposes have been molded. (For example, Japanese Patent Application Laid-open No. 55-139143,
(Japanese Unexamined Patent Application Publication No. 57-195555, etc.).

However, it has been difficult to mold a complex-shaped core with uniform strength and good dimensional accuracy.

(Objective of the Invention) The present invention has been made in view of the above circumstances, and provides a complex-shaped green sand core with uniform strength and good dimensional accuracy, in particular a green sand core whose thickness at the center is smaller than that at the periphery. The purpose of the present invention is to provide an apparatus capable of molding green sand cores having a larger shape.

(Structure of the Invention) Hereinafter, the present invention will be described in detail based on Examples. FIG.
A lower frame 2 having a rectangular plane, two pillars 3 and 4 facing each other on two long sides of the lower frame 2, and an upper frame 5 connecting the upper ends of the pillars 3 and 4. It consists of At a position slightly closer to the lower end of the gate-shaped frame Y, there is a roller frame 6 having a rectangular plane and a large number of rollers 4 with flanges attached to opposing surfaces of two long sides of the frame 6.
A roller conveyor 8 consisting of a It is supported by a pillar 9 erected above. For convenience of explanation, the roller conveyor 8 will be referred to as a lower roller conveyor.

A roller conveyor 11 having substantially the same shape as the lower roller conveyor 8 is also horizontally arranged at a position slightly closer to the upper end of the gate-shaped frame 1, and one end of the roller conveyor 11 is connected to the support column 3, 4, and the other end side is supported by a column 12 erected on the right end of the lower frame 2 in the direction of the drawing. For convenience of explanation, the roller conveyor 11 will be referred to as an upper roller conveyor.

On the lower frame 2, an upwardly facing cylinder 13 is installed, located approximately in the center of the drawing and directly below the lower roller conveyor 8, and the tip of the piston rod of the cylinder 13 has a surface area and a shape. A table 15 having a bottom area and shape substantially equal to the bottom area and shape of a mold 14, which will be described later, is fixed thereto, and the table 15 is designed to pass through the hollow part of the roller frame 6 of the lower roller conveyor 8 and move up and down. There is.

A frame-like running frame 16 with an open top and bottom is placed on the lower roller conveyor 8, and a mold 14 having a flange on the outer periphery near the upper end is mounted on the running frame 16. They are mounted so as to be separable via the flange, and are aligned by positioning pins (not shown).

A left-facing cylinder 17 is disposed at the right end of the lower roller conveyor 8, and the tip of the piston rod of the cylinder 17 is connected with a pin to the right side wall of the traveling frame 16, so that the cylinder 17 Due to the expansion and contraction operation, the mold 14 is transferred to the lower roller conveyor 8 via the traveling frame 16.
It is possible to move back and forth on the top.

A stepped recess 18 is formed on the upper surface side of the upper half of the mold 14, and a cavity 19 is formed in the lower half of the mold 14. It communicates with the atmosphere through an opening 21 provided on the bottom surface of the tank. The design is such that there is a slight gap between the bottom surface level of the mold 14 and the top surface level of the table 15 when the cylinder 13 is retracted. An extrusion plate 23 having a plurality of extrusion pins 22 implanted on its upper surface is disposed in the cavity 19.
2 penetrates the bottom side of the upper half of the mold 14 and can protrude into the stepped recess 18 .

Note that the stepped recess 18 of the mold 14 may be a recess without a step.

A traveling frame 24 in the form of a frame with an open top and bottom is also placed on the upper roller conveyor 11, and a mounting member 25 is reliably placed on the traveling frame 24, both of which are not shown in the figure. It is designed to be aligned using a locating pin that does not need to be aligned. A recess 26 having the same shape as the upper surface of the desired core is formed at the center of the lower surface of the mounting member 25, and is slid into the upper recess of the mold 14 to a predetermined depth. A compression mold 27 defining a cavity of a predetermined shape is fixed to the compression mold 27, and a stopper 28 is fixed to surround the compression mold 27. It is possible to touch it.

A left-facing cylinder 29 is also disposed at the right end of the upper roller conveyor 11, and the tip of the piston rod of the cylinder 29 is connected with a pin to the right side wall of the traveling frame 24, so that the cylinder 29 The compression mold 27 is compressed by the expansion and contraction operation.
can reciprocate on the upper roller conveyor 11 via the traveling frame 24 and the mounting member 25.

Note that when the mold 14 is located directly above the table 15, the mold 14 can move up and down through the hollow part of the roller frame of the upper roller conveyor 11 via the table 15. ing.

Further, a predetermined distance exists between the upper surface level of the mold 14 in a normal state and the lower surface level of the compression mold 27.

Above the table 15 is a blow tank 31.
is supported by the upper frame 5, and a predetermined amount of green sand can be stored in the blow tank 31, and compressed air can be supplied from a compressed air source (not shown). There is.

Note that 32 is a slide gate for opening and closing the upper end opening of the blow tank 31, and 33 is a cylinder for reciprocating the slide gate 32.

At the lower end of the blow tank 31, a recess 34 deeper than the height of the desired upper surface of the core is formed at the center of the lower surface thereof, and the core is slid into the upper recess of the mold 14 to a predetermined depth. A sand blowing mold 36 that defines a cavity 35 having a predetermined shape is fixed thereto, and a sand blowing hole 37 is inserted through the center of the bottom plate of the blow tank 31 and the center of the sand blowing mold 36. is drilled. Reference numeral 38 denotes an exhaust port having one end opened around the lower surface of the sand blowing mold 36 and the other end opened in the side wall of the mold 36.
9 is a vent plug. The blow tank 31
A stopper 41 is fixed to the outer periphery of the lower surface of the mold 36 so as to surround the sand blowing mold 36.
The lower surface of the mold 14 can be brought into contact with the outer periphery of the upper surface of the mold 14 . It should be noted that the design is such that there is a slight gap between the upper surface level of the mounting member 25 in its normal state and the lower surface level of the sand blowing mold 36.

On the lower frame 2, on the left side as viewed from the drawing and directly below the lower roller conveyor 8, an upwardly facing cylinder 42 is supported by the support 9, and the piston rod of the cylinder 42 has a piston rod at its tip. A push-up plate 43 having a shape that can be loosely fitted into the bottom opening 21 of the mold 14 is fixed. Note that there is also a slight gap between the bottom surface level of the mold 14 and the top surface level of the push-up plate 43 when the cylinder 42 is retracted.

(Function) To explain a series of steps for molding a green sand core using the apparatus configured as described above, Table 1
5. With the push-up plate 43 and the compression mold 27 being retracted, as a first step, the cylinder 17 is retracted to position the mold 14 directly above the table 15. As a second step, when the cylinder 13 is extended and the table 15 is raised, the top surface of the table 15 comes into contact with the bottom surface of the mold 14 and lifts it up, thereby lifting the mold 14 from the traveling frame 16. Separated, upper roller conveyor 1
It passes through the hollow part of the roller frame at 1 and rises. Eventually, the sand blowing mold 36 relatively slides and fits into the upper recess of the mold 14, and when it is fitted to a predetermined depth, the outer circumference of the upper surface of the mold 14 comes into contact with the stopper 41, and the cylinder 13 The elongation of the mold 14 and the rise of the mold 14 are stopped. As a result, a cavity 35 having a predetermined shape is defined by the stepped recess 18 of the mold 14 and the sand blowing mold 36. Now, to explain the shape of the cavity 35 in detail, the shape of the cavity 35 will be explained in detail.
5 has a shape in which the stepped recesses are vertically opposed, as shown in Fig. 2, whereas the stepped recesses in the lower half form the shape of the final product (core). ,
The dimension of the upper half part is enlarged in the vertical direction compared to the shape of the final product, and the enlarged dimension is different between the central thick part and the peripheral thin part. That is, the enlarged dimension b' in the central thick part is larger than the enlarged dimension a' in the peripheral thin part, and the ratio of the two dimensions is the same as that of the central thick part b and the peripheral thin part a in the final product.
It is made equal to the dimensional ratio of .

As a third step, compressed air is supplied into the blow tank 31 whose upper end opening is closed, and green sand stored therein is blown into the cavity 35 through the sand blowing hole 37 and filled. At this time, the compressed air blown into the cavity 35 together with the sand is discharged into the atmosphere through the exhaust hole 38.

After the blowing and filling of the green sand is completed, the residual pressure in the blow tank 31 is eliminated, and as a fourth step, the cylinder 13 is retracted and the mold 14 is moved to the table 1.
5, the mold 14 and the sand blowing mold 36 are separated, and as a result, a core preform is obtained while being held in the stepped recess 18 of the mold 14. The mold 14 will eventually become a traveling frame 16.
The table 15 is latched to the top and stops descending.
One person descends to the lower end.

As a fifth step, the cylinder 29 is extended and the compression mold 27 is moved between the sand blowing mold 36 and the mold 1.
4 and is stopped at a position directly above the mold 14. Then, in a sixth step, the cylinder 13 is extended again to lift the mold 14 through the table 15. Eventually, the upper surface of the core preform held on the mold 14 comes into contact with the lower surface recess 26 of the compression mold 27 and lifts it, thereby separating the mounting member 25 from the traveling frame 24. The back surface of the mounting member 25 contacts the lower surface of the sand blowing mold 36. The cylinder 13 continues to extend, so that the compression mold 27 relatively slides into the upper recess of the mold 14 and releases the core held on the mold 14. Compress the preform. The compression mold 2
7 is inserted to a predetermined depth, the outer circumference of the upper surface of the mold 14 comes into contact with the stopper 28 and the cylinder 13
The extension of the table 15 and the raising of the mold 14 are stopped. As a seventh step, when the cylinder 13 is retracted and the compression mold 27 and the mold 14 are lowered together with the table 15, the compression mold 27 is eventually attached to the traveling frame 2 through the mounting member 25.
The compression mold 27 is thereby separated from the mold 14, and as a result, a core 44 of a desired shape is obtained while being held in the stepped recess 18 of the mold 14. . The mold 14 is eventually stopped on the traveling frame 16 and stops descending, and the table 15 descends alone to the lower end. As an eighth step, the cylinder 17 is extended and the mold 1 is expanded.
4 to just above the push-up plate 43. Then, in the ninth step, when the push-up plate 43 is raised by the extension operation of the cylinder 42, the push-up plate 43 passes through the lower end opening 21 of the mold 14, and the push-up plate 23 inside
is pushed up, which causes the ejection pin 22 to move into the mold 14.
The core 44 held in the stepped recess 18 of the recess 1
Push out from 8.

After taking out the core 44, the push-up plate 43 is lowered to retract the push-out pin 22, and in a tenth step, the cylinder 17 is retracted to move the mold 14 to a position directly above the table 15. Restore until. During this time, green sand for the next blowing is put into the blow tank 31, and the compression mold 27 is compressed between the sand blowing mold 36 and the mold 14 by the contraction operation of the cylinder 29. Being moved out of position.

The above steps are considered as one cycle, and the same cycle is repeated thereafter, whereby green sand cores of the same shape are successively molded.

(Effects of the Invention) As is clear from the above description, the present invention is capable of forming green sand cores in which the thickness of the central part is larger than that of the peripheral parts, and in the first step, the thickness of the green sand core is larger than that of the final shape of the product. A cavity with large vertical dimensions is defined, green sand is blown and filled into the cavity to form a preform, and in the second step, the preform is compression molded into a final product (core). However, the unique point of the present invention is that the enlarged dimension of the central thick-walled part in the preform is larger than the enlarged dimension of the peripheral thin-walled part, and the ratio of both enlarged dimensions is greater than that of the central thick-walled part in the final product. The dimensional ratio with the thin wall portion is made equal. By compressing such a preform into the shape of a final product, it is possible to obtain a core with substantially uniform strength in the central thick part and the peripheral thin part. In addition, since the green sand in the thick central part of the preform is well compacted, the transferability in this part is improved and a core with good dimensional accuracy can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cutaway front view of essential parts of a green sand core molding apparatus according to the present invention, and FIG. 2 is a dimensional comparison diagram of a cavity for a preformed core and a cavity for a final product. 8: Lower roller conveyor, 11: Upper roller conveyor, 14: Mold, 15: Table, 1
8, 26, 34: recess, 25: mounting member, 27:
Compression type, 31: Blow tank, 35: Cavity, 36: Sand blowing type, 37: Sand blowing hole, 4
4: Middle child.

Claims (1)

[Claims] 1. The mold 14 is placed below the mold 14 which has a recess 18 formed thereon, and a table 15 that can be raised and lowered is provided, and a blow tank 31 is provided above the mold 14. At the lower end of the blow tank 31, a recess 34 deeper than the height of the desired upper surface of the core 44 is formed at the center of the lower surface, and can be slid into the recess 18 of the mold 14 to a predetermined depth. A sand blowing mold 36 is fixed, and a sand blowing hole 37 is bored through the sand blowing mold 36 and the bottom plate of the blow tank 31, and the back side thereof is on the lower surface of the sand blowing mold 36. Mounting member 25 that can be brought into contact
A recess 26 having the same shape as the upper surface of the desired core 44 is formed in the center of the lower surface of the mold 14, and a compression mold 27 that can be slid and fitted into the recess 18 of the mold 14 to a predetermined depth is fixed. Green sand core molding characterized in that the mounting member 25 and the compression mold 27 are disposed at a position between the lower surface of the sand blowing mold 36 and the upper surface of the mold 14 in a normal state so as to be freely accessible. Device.