JP2863028B2 - Pressure casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure casting apparatus for performing casting by pressing a molten metal supplied into a cavity of a mold.

[0002]

2. Description of the Related Art In a pressure casting apparatus for applying a constant pressure to a molten metal supplied into a cavity of a mold, a mold composed of a plurality of split dies is used as a mold to counter the pressure. A hydraulic cylinder is used as a driving means for opening and closing a split mold that constitutes a mold for taking out the cast found.

In this case, in order to bring the plurality of split dies into good contact with each other, a hydraulic cylinder is disposed at the center of one of the split dies, the split die is driven, and the other split die is pressed. You are going to.

On the other hand, in a pressure casting apparatus for mechanically pressurizing molten metal supplied into a cavity or a runner of the mold, an apparatus using a hydraulic cylinder as a pressurizing means for pressurizing the molten metal is known. is there.

In such a pressure casting apparatus, the pressing direction of the pressing means and the opening / closing direction of the mold by the driving means may be the same due to the shape of the cavity and the arrangement of the runner. In some cases, it is preferable that the hydraulic cylinder as the pressure means is installed at the center of the split mold in accordance with the shape of the cavity or the runner.

Conventionally, in such a case, the pressurizing means is installed at a required position which is a central portion of the split mold,
The driving means is displaced from the central portion of the split mold so that both the pressing means and the driving means are arranged in the same split mold.

[0007]

However, if the driving means is displaced from the center of the split mold as described above, the surface pressure due to the pressing of the split mold to another split mold becomes non-uniform, and the adhesion becomes poor. Deterioration is one of the causes of casting flash.

The present invention has been made based on such a background. In this type of pressure casting apparatus, even if the pressing means is arranged at the central portion of the split mold, another split mold of the split mold is used. It is an object of the present invention to reduce the occurrence of burrs and the like without impairing the adhesion to a mold.

[0009]

In order to achieve this object, the invention according to claim 1 comprises a driving means for opening and closing a mold comprising a plurality of divided dies, and a driving means for opening and closing a cavity formed in the mold. A pressure casting device having a pressurizing means for mechanically pressurizing the supplied molten metal, wherein the driving means and the pressing means are installed in the same direction in the same split mold, A double-acting two-stage hydraulic cylinder is mounted in the center of the split mold, and the first stage of the hydraulic cylinder is the drive unit and the second stage is the pressurizing unit.

[0010]

According to the first aspect of the present invention, in this type of pressure casting apparatus, a double-acting two-stage hydraulic cylinder is mounted on the center of a split mold, and Since the step is a pressing means, the molten metal in the mold can be pressurized at the center of the split mold.

[0011] Even if the pressure of the molten metal pressurized by the second stage acts in the direction of separating the mold inside the cavity or the like of the mold composed of these split molds, the first stage is maintained. As a driving means, the split mold is pressed at its central portion, and can be brought into close contact with other split molds with a uniform surface pressure against the pressing force of the molten metal. Can be reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. The pressure casting apparatus of this embodiment is formed as a molten metal forging apparatus.

In the drawing, reference numeral 1 denotes a pressure casting device, 2 denotes a fixed ram, and 3 denotes a moving ram. The moving ram 3 is driven toward and away from the fixed ram 2 by a driving device (not shown). (Arrow A in FIG. 1).

One end of a bracket 4 is fixed to the moving ram 3, and a first hydraulic cylinder 5 is mounted on the other end of the bracket 4.

The first hydraulic cylinder 5 is composed of a double-acting two-stage hydraulic cylinder, and has a large-diameter first-stage cylinder portion (hereinafter simply referred to as a first stage) 6 and a small-diameter second stage. And a cylinder portion (hereinafter, simply referred to as a second stage) 7.

The first hydraulic cylinder 5 is installed in a direction perpendicular to the direction A of contact and separation of the moving ram 3 and is shown in FIG.
The middle arrow B indicates the direction of expansion and contraction of the first stage 6, and the arrow C indicates the direction of expansion and contraction of the second stage 7.

A metal mold 11 is mounted on the pressure casting apparatus 1. The metal mold 11 is composed of a fixed mold 12, a movable mold 13 and an end face mold 14.

The fixed mold 12 is fixed to the fixed ram 2 via a fitting, and the movable mold 13 is fixed to the movable ram 3 via a fitting.

The end face mold 14 is provided with the first hydraulic cylinder 5
Is fixed to the first stage 6 via a mounting plate 15.

The mold surfaces 12a, 13a and 14 of the fixed mold 12, the movable mold 13 and the end face mold 14 pressed against each other.
In a, a cavity, a runner and the like are formed as follows.

First, the movable mold 13 will be described with reference to FIG.

The mold surface 13a of the movable mold 13 has a cavity portion 13b which forms approximately a half circumference of the outer shape of the casting product elongated in the left-right direction in the figure, and a runner 17 extending downward from the sprue 16.
The runner 17 and the cavity portion 1 are formed.
A half-cylinder-shaped cylinder portion 13c extending in the vertical direction is formed between the cylinder portion 13c and the cylinder portion 3b.

In the drawing, the left end of the cavity 13b is formed in an open state on the mold surface 13a of the movable mold 13, and this portion is similar to the same end of the cavity 12b of the fixed mold 12 described later. Along with the part, the end face mold 14 is closed by the mold surface 14a.

As shown in FIG. 3, the mold surface 12a of the stationary mold 12 has a cavity 12b corresponding to the cavity 13b of the movable mold 13 and forms the other half of the outer shape of the casting product. A half-split cylinder portion 12c corresponding to the portion 13c is formed, and the right end portion of the cavity portion 12b in the figure is open as in the case of the movable die 13.

A tapered portion 12d is formed at the right end of the fixed die 12 in the drawing.

A second hydraulic cylinder 1 comprising a double-acting two-stage hydraulic cylinder similar to the first hydraulic cylinder 5 is provided below the cylinder portion 12c of the fixed die 12.
8 are installed.

The first stage 21 of the second hydraulic cylinder 18
, A piston 25 is fixed, and a rod 24 is fixed to a second stage (not shown) of the second hydraulic cylinder 18.

The piston 25 is mounted on the cylinder part 12c of the fixed mold 12 and the cylinder part 13c of the movable mold 13 so as to advance and retreat in a cylinder part having a circular cross section formed by abutting the cylinder part 12c. The bottom portion is closed, and the molten metal supplied through the runner 17 is temporarily stored above the piston 25, and the piston 25 is driven upward to remove the molten metal from the cavity portion 12b,
The cavity 13b is filled under pressure.

The rod 24 is installed so as to be able to advance and retreat through the axial center of the piston 25,
After the piston 25 reaches the uppermost position in 2c and 13c, the rod 24 is further advanced and driven to apply a higher pressure to the molten metal in the cavities 12b and 13b to perform molten forging. .

In some cases, the installation of the rod 24 is omitted, and the amount of molten metal supplied above the piston 25 is made somewhat large, so that a higher pressure is generated by the piston 25 and molten metal forging is performed. It is also possible to make it.

As shown in FIG. 2, the end face mold 14 closes the fixed mold 12, the movable mold 13 and the open ends of the cavities 12a, 13a by abutting from the end face side.
The end face of the casting product is formed, and a cavity 14b conforming to the shape of the end face portion of the casting product is formed at the center of the mold surface 14a of the end face mold 14.

Then, the cavity 1 of the end face mold 14 is formed.
An axially extending punch hole 26 is formed at the center of the casting formed by the cavity at the center of the mold 4b, and a tapered portion 14d (see FIG. 1) is formed.

At the central portion of the outer surface of the end face mold 14 which is formed as described above, the first hydraulic cylinder 5 is disposed perpendicular to the outer surface, and the tip of the first stage 6 is connected to the first hydraulic cylinder 5. A punch 27 for molten metal forging attached to the second step 7 is inserted through the punch hole 26 so as to be able to advance and retreat, while being fixed to a central portion of the outer surface of the end face mold 14 via a mounting plate 15.

[0034] Therefore, the end face mold 14 is brought into a state of being in close contact with the other fixed mold 12 and the movable mold 13 by pressing the central portion thereof by the first step 6, so that casting is possible. The occurrence of burrs and the like is reduced as compared with the related art.

It should be noted that the concept of the central portion in the above is not limited to the center of the end face mold 14 in a strict sense, but includes the central portion in a broad concept that it is not the peripheral portion of the end face mold 14.

The tapered portion 14d is a portion which engages with the tapered portion 12d formed on the fixed die 12 as shown in FIG. 14 is held in a state of being engaged with the fixed mold 12 to prevent the end face mold 14 from retreating due to the pressure of the molten metal in the cavity.

The pressure casting apparatus 1 equipped with such a mold 11 operates as follows.

The pressure casting apparatus 1 in which the mold 11 is open.
First, the first stage 6 of the first hydraulic cylinder 5 is extended to make the end face mold 14 face a predetermined position of the movable mold 13.

Thereafter, the movable ram 3 is moved toward the fixed ram 2, and the mold surface 13 a of the movable mold 13 is brought into contact with the mold surface 12 a of the fixed mold 12.

With the movement of the movable mold 13, the tapered portion 14d of the end face mold 14 is moved to the mold surface 1 of the fixed mold 12.
By engaging with a tapered portion 12d formed on one side of 2a, it is sandwiched and fixed between the fixed die 12 and the movable die 13, and the state shown by a virtual line in FIG. 1 is obtained.

Thereafter, the first stage 21 of the second hydraulic cylinder 18 is driven to ascend, and the upper end of the piston 25 attached to the first stage 21 is fixed to the lower ends of the cylinder portions 12c, 13c of the fixed mold 12 and the movable mold 13. Insert into the opening and close.

In this state, when a predetermined amount of molten metal is supplied to the mold 11 from the gate 16, the supplied molten metal is temporarily stored on the piston 25 in the cylinder portions 12 c and 13 c.

Thereafter, the first stage 21 of the second hydraulic cylinder 18 is further driven up to a predetermined position, whereby the molten metal is filled into the cavities 12b and 13b under pressure.

The rod 24 mounted on the second stage of the second hydraulic cylinder 18 has a rod 24 which will be described below according to the casting defect caused by the molten metal supplied to the cavities 12b and 13b. Second stage 7 of one hydraulic cylinder 5
At the same time or before and after, the piston 25 is driven to advance further upward from the upper end of the piston 25 to enhance the effect of forging the molten metal.

As described above, the cavity portions 12b, 1
When the molten metal supplied into 3b starts to solidify appropriately, the second stage 7 of the first hydraulic cylinder 5 is driven to extend.

As a result, the molten metal forging punch 27 mounted on the second stage 7 is driven into the cavities 12b and 13b through the punch holes 26, and is driven.
The molten metal filled in b, 13b is pressurized to a higher pressure to perform forging, and a cast product with less casting defects can be obtained.

The removal of the cast product is performed by retracting the required members such as the respective split dies in the reverse order, so that the description is omitted.

In this embodiment, the first and second hydraulic cylinders 5 and 18 are controlled in the same manner, and the first and second hydraulic cylinders 5 and 18
Each of the stages is controlled so as to be capable of being driven to extend and contract independently.

In the following, the control circuit of the first hydraulic cylinder 5 shown in FIG. 4 will be described, and the description of the second hydraulic cylinder 18 will be omitted because it is the same.

The hydraulic cylinder 5 is connected to the first stage 6 as described above.
A double-acting two-stage hydraulic cylinder comprising a first stage 6 and a second stage 7.
And a second oil chamber 6c formed by a piston 7a, a first oil chamber 7b, and a second oil chamber 7c on the axial center side of the second oil chamber 6c. A step 7 is formed.

In the hydraulic cylinder 5,
The supply and discharge of pressure oil to and from the first oil chamber 7b of the second stage 7 is performed through the first oil chamber 6b of the first stage 6.

In the figure, 31 is a pressure oil supply line, 32 is a return line, and 33 is a control circuit of the first hydraulic cylinder 5.

The control circuit 33 includes a first circuit 34 for controlling the expansion and contraction driving of the first stage 6 of the first hydraulic cylinder 5.
And a second circuit 35 for controlling the expansion / contraction drive of the second stage 7.

Since the first circuit 34 and the second circuit 35 have substantially the same configuration, the structure of the first circuit 34 will be mainly described below. Only the differences from the first circuit 34 will be described, and the common parts will be denoted by the same reference numerals in the drawings and description thereof will be omitted.

That is, in the first circuit 34, the check valve 3 is connected to the oil passage 36 branched from the pressure oil supply pipe 31.
A normally open pressure reducing valve 38 is provided via the switch 7, and the hydraulic pressure from the normally open pressure reducing valve 38 is supplied to one port of a switching valve 41 composed of a 4-port 3-position switching valve.

The switching valve 41 mainly switches the left and right solenoids on and off to switch the first stage 6.
The switching of the operation is controlled.

The oil passage 42 branched from the return line 32 is connected to the oil passage 36 in the switching valve 41.
Is connected to another port on the same side.

The oil passage 4 extending from the second oil chamber 6c
4 is connected to the other port of the switching valve 41 via a flow control valve 47 in which a variable throttle 45 and a check valve 46 are connected in parallel.

An oil passage 43 extending from the first oil chamber 6b is provided with a switching valve of the second circuit 35 (hereinafter, indicated by 41 'for distinction).
After branching off from an oil passage (to be referred to as 43 'hereinafter for distinction), the oil passage is connected to another port of the switching valve 41 of the first circuit 34 via the same flow control valve 47 as described above.

In the drawing, reference numeral 48 denotes a pressure gauge, and 49 denotes an adjusting valve for adjusting the operating pressure of the normally open pressure reducing valve 38.

In the illustrated control circuit 33, when the first stage 6 is reduced, the switching valve 41 'of the second circuit 35 is set to the neutral position, and the switching valve 41 of the first circuit 34 is shifted to the left. Switch to position.

As a result, the oil pressure from the pressure oil supply line 31 reaches the oil passage 44 from the oil passage 36 via the switching valve 41,
Oil chamber 6c is enlarged. At the same time, the first oil chamber 6b
Is connected to a variable throttle 45 and a switching valve 41.
, The first oil chamber 6b is reduced in accordance with the expansion of the second oil chamber 6c,
Stage 6 performs a reduction operation.

At this time, since the switching valve 41 'of the second circuit 35 is in the neutral position, the pressure oil of the second stage 7 does not flow,
The second stage 7 does not expand or contract and is kept in an independent state.

Conversely, when the first stage 6 is to be extended, the switching valve 41 of the first circuit 34 is set to the right while the switching valve 41 'of the second circuit 35 is kept at the neutral position as described above. Switch to the offset position.

As a result, the oil passage 36 from the pressure oil supply pipe 31 is connected to the oil passage 43 via the switching valve 41,
The oil passage 44 connected to the second oil chamber 6c is connected to the return line 32 via the switching valve 41, so that the first stage 6 performs the extension operation.

Although the first oil chamber 7b of the second stage 7 communicates with the first oil chamber 6b of the first stage 6 as described above, the switching valve 41 'of the second circuit 35 is provided. Is in a neutral state, and the flow of pressure oil from the second oil chamber 7c of the second stage 7 to the return line 32 is prohibited, so that the second stage 7 does not expand or contract.

When the second stage 7 is operated to expand and contract, the first stage switching valve 41 is operated in the same manner as in the first stage 6.
In the neutral state, and in this state, the switching valve 4 of the second circuit 35
If 1 'is appropriately set as the offset position, only the second stage 7 can be independently extended and contracted without the extension and contraction of the first stage 6.

In the pressure casting apparatus 1 of this embodiment, a double-acting two-stage hydraulic cylinder is used as the first and second hydraulic cylinders 5 and 18 as described above.
A control circuit is used to drive the first and second stages of the stage hydraulic cylinder to extend and contract independently of each other.

Therefore, when using molds having cavities of various shapes and capacities, or in casting operations where there are many uncertain factors such as fluctuations in the temperature of the molten metal, it is necessary to appropriately drive each stage of these hydraulic cylinders as necessary. And the efficiency of the casting operation can be improved.

In particular, when the molten metal supplied to the mold is temporarily stored in the cylinder during casting, and the molten metal is pressurized and filled into the cavity with a piston, the temperature of the molten metal tends to decrease. If the temperature is low, hot water may be clogged. However, since the respective stages of the double-acting two-stage hydraulic cylinder can be independently and appropriately driven as in the above-described embodiment, it is possible to operate the stage as needed. Can be easily solved.

In the above-described embodiment, the present invention is based on the pressure casting apparatus formed as a molten metal forging apparatus. However, the present invention is not limited to this, and may be another pressure casting apparatus such as a die casting apparatus. The same can be implemented.

[0072]

As described above, according to the first aspect of the present invention, a double-acting die 2 is provided in this type of pressure casting apparatus.
The stage hydraulic cylinder is mounted on the center of the split mold, and the second stage of the double-acting two-stage hydraulic cylinder is used as the pressurizing means, so that the molten metal in the mold can be pressurized at the center of the split mold. it can.

Then, even if the pressure of the molten metal pressurized by the second stage acts in the direction of separating the mold inside the cavity or the like of the mold composed of these split molds, the first stage is maintained. As a driving means, the split mold is pressed at its central portion, and can be brought into close contact with other split molds with a uniform surface pressure against the pressing force of the molten metal. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a top view of a pressure casting apparatus according to an embodiment.

FIG. 2 is a side view showing a moving ram side.

FIG. 3 is a side view showing a fixed ram side.

FIG. 4 is a control circuit diagram of a first hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure casting apparatus 5 1st hydraulic cylinder 6 1st stage cylinder part 7 2nd stage cylinder part 11 Die 12 Fixed type 13 Moving type 14 End surface type 33 Control circuit 34 1st circuit 35 2nd circuit

Claims (2)

(57) [Claims] 1. A pressure casting apparatus comprising: a driving means for opening and closing a mold comprising a plurality of split molds; and a pressure means for mechanically pressurizing a molten metal supplied into a cavity formed in the mold. An apparatus in which the driving means and the pressurizing means are installed in the same split mold in the same direction in the same direction, wherein a double-acting two-stage hydraulic cylinder is mounted at the center of the split mold, A pressure casting apparatus, wherein a first stage of a cylinder is the driving unit and a second stage is the pressing unit. 2. The pressure casting apparatus according to claim 1, wherein
The first and second stages of the double-acting two-stage hydraulic cylinder,
A pressure casting apparatus characterized by having a control device capable of independently expanding and contracting drive.