JPH10175056A - Production of long and thin casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the fear to damaging of a thin casting by forming a position which forms the part surrounded with reinforced ribs in the casting on the die surface of a cavity in a permanent die, as the separating divided die from the die main body of the permanent die and separating the divided die previous to the die main body. SOLUTION: After filling and solidifying molten metal into the cavity 15 with the gravity, a hydraulic cylinder 34 is driven to shrink previous to the die separation to the die main body of an upper die (permanent die) 3 by ascending a movable platen 6. The divided die 31 is detached from the casting 16 in the part formed with the divided die 31 having large width size of the reinforced ribs 17 by ascending the divided die 31 by several mm. An insert pin 36 set to the die main body of the upper die 3 and a movable pin 38 supported to a lower die 4 and retractable with a hydraulic cylinder 37 are used into a boss hole 35. At the time of forming this boss hole 35, the movable pin 38 is retreated previous to the die separation to the die main body of the upper die 3 from the casting 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long thin casting by pouring a molten metal into a permanent mold at a pressure as low as gravity.

[0002]

2. Description of the Related Art Conventionally, thin castings are generally formed using a permanent mold such as a mold.

However, thin castings formed using a permanent mold as described above have relatively small dimensions, and long castings are not generally mass-produced.

[0004]

That is, when a thin casting is formed, it is necessary to integrally form a reinforcing rib in order to secure the strength, but in the case of a long thin casting, The height of the reinforcing ribs is also large, and if a certain draft is given to such a large reinforcing rib, the thickness of the base of the reinforcing rib will increase, and the thickness of the original cast product part will also be out of balance with the reinforcing rib. It is necessary to set the thickness thick.

[0005] For this reason, when a long thin casting is manufactured, if the draft of the reinforcing rib is set to be small, the draft of the reinforcing rib is small, so that it is difficult to release the reinforcing rib part. Since the thickness of the cast product to be manufactured is thin and long, when the long thin cast product is released from the permanent mold, the reinforcing rib portion and the thin original cast product portion are easily damaged. Long thin castings could not be mass-produced.

The present invention has been made in view of the above circumstances, and is a technique for manufacturing a thin cast using a permanent mold. The present invention reduces damage when releasing a cast from a long thin cast. Is to be mass-produced.

[0007]

In order to solve such a problem, the invention according to claim 1 is directed to a method of manufacturing a thin casting by pouring a low-pressure molten metal into a cavity of a permanent mold. Forming a part of the mold surface and forming a portion surrounded by the reinforcing ribs of the casting, as a separate mold separate from the mold body of the permanent mold, and release the divided mold prior to the mold body, Thereafter, the mold body is released from the mold body.

According to a second aspect of the present invention, in the method for producing a long thin casting according to the first aspect, the mold surface of the split mold has a mold surface of a mold body adjacent to the periphery of the split mold. And a groove for forming a groove-shaped reinforcing rib forming portion along the entire circumference of the split mold, and connecting between opposing portions of the reinforcing rib forming half on the mold surface of the split mold. And forming a long thin casting with a reinforcing rib formed in a shape.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention in a gravity casting method will be described below with reference to the drawings.

2 and 3, reference numeral 1 denotes a casting apparatus for gravity casting, 2 denotes a mold as a permanent mold,
The mold 2 includes an upper mold 3 and a lower mold 4, and 5 is a gate section.

The upper die 3 has a support plate 11 and a support rod which are arranged in the longitudinal direction of the die 2 on an upper die mounting plate 7 whose periphery and center are fixed to a movable platen 6 of a casting machine by bolts. 12 is rigidly installed.

The lower mold 4 is a fixed platen 1 of a casting machine.
The lower die mounting plate 14 is fixedly mounted on the lower die mounting plate 14 via the support plate 11 and the support rod 12 similarly to the upper die 3.

The upper mold 3 and the lower mold 4 are formed with product forming portions 3b, 4b (corresponding to the mold surface in the present invention) on the divided surfaces 3a, 4a of the upper mold 3 and the lower mold 4, respectively. The product forming portions 3b and 4b are abutted to form a cavity 15 having a required shape.

In this embodiment, the casting 16 cast by the mold 2 is a so-called long thin casting made of an aluminum alloy (AC4CH) and has a generally thin plate-like bent structure. For example, it is a long part which is used as a part of a body frame of a passenger car and has a total length of about 1.5 m in a longitudinal direction.

Since the casting 16 has a generally thin plate-like bent structure as described above, the casting 16 may be clearly seen from the surface shape of the product forming portion 3b of the upper die 3 shown in FIG. A large number of reinforcing ribs 17 are formed integrally with each other to secure the required strength.

The cavity 15 of the mold 2 for forming such a casting 16 is formed between the divided surfaces 3a and 4a of the upper mold 3 and the lower mold 4 as described above. The cavities 15 include end cavities 21 corresponding to both side ends of the casting 16 and intermediate cavities 22 connecting between the end cavities 21 (see FIG. 4). .

A gate 5a is arranged on the side of the intermediate cavity 22 and between the end cavities 21. In the mold 1, one end of the gate 5a is provided. The cavity 21, the gate 5 a, and the end cavity 21 on the other end are arranged in the longitudinal direction of the mold 2 so that the heat source is dispersed throughout the mold 2, and the overall thermal deformation of the mold 2 is improved. Has been reduced.

In the upper mold 3, the split dies 31 are respectively provided in the end cavities 21 on both sides described above.
Are installed symmetrically. Reinforcing rib forming portions 26 and the like are formed on the mold surfaces of these divided molds 31 as described later, so that the mold surfaces of these divided molds 31 and the molds of the mold bodies 32 located around the divided molds 31 are formed. The product forming portion 3b, which is the die surface of the upper die 3, is formed by disposing the surfaces in a required state.

After the upper mold 3 having the above-described configuration is set on the lower mold 4, a molten aluminum alloy is supplied by gravity through the gate 5a (FIG. 3).
It is supplied to the left and right end cavities 21 via a runner 23 bypassing the outside of the cavity 15 to fill the end cavities 21 and to fill these end cavities 21.
And is also filled into the intermediate portion cavity 22.

Normally, the middle cavity 2 having a small capacity is used.
Although a small amount of molten metal for filling 2 is easily radiated and solidified, the molten metal is supplied through the end cavity 21 having a large capacity and maintained at a high temperature level as described above. Since a small amount of molten metal can be supplied while suppressing heat radiation, and a decrease in the temperature of the molten metal supplied to the intermediate portion cavity 22 is reduced, a good molten metal can be reliably supplied to every corner of the cavity 15. .

Each part of the runner 23 is provided with a ceramic filter 24 having a large number of pores and a feeder 25a, and 25b in FIG.

In this way, the molten metal of the aluminum alloy (AC4CH) is supplied from the gate 5 to the cavity 15 by gravity, and the molten metal is solidified in the cavity 15.
The casting 16 having a predetermined shape also including the reinforcing rib 17 formed by the split mold 31 is obtained by releasing the mold 2 from the mold 2.

In this embodiment, since the upper mold 3 has the split mold 31 as described above, the upper mold 3 from the casting 16 solidified in the cavity 15, that is, the split mold 31 and the mold body 32. Is performed as follows.

In the following, only the part relating to the split mold 31 in the end cavity 21 shown on the left side in FIG. 4 will be described, and the one on the right side has a symmetrical shape and the operation and the like are the same. Therefore, the description is omitted.

First, the split mold 31 and the like will be described in more detail with reference to FIGS. 5 and 1. FIG. 5 is an enlarged plan view of a main part of the end cavity 21 shown on the left side in FIG. The mold body 32 of the mold 3 has a split mold 31
A through-hole 33 having the same shape as that of FIG. 1 is formed, and the split mold 31 is inserted into the through-hole 33 to form a product forming portion 3b having a required shape.

The upper die 3 in this state is mounted on the upper die mounting plate 7 of the movable platen 6 of the casting machine as described above, and is brought into abutment with the lower die 4 mounted on the lower die mounting plate 14 to have a required shape. (See FIG. 1).

Further, a reinforcing rib forming half portion 27 is formed over the entire outer periphery of the split mold 31 in plan view. The reinforcing rib forming half portion 27 is a portion in which the reinforcing rib 17 having a required cross-sectional shape is formed by the reinforcing rib forming half portion 29 formed on the mold body 32 adjacent to the split mold 31.

On the surface forming the product forming portion 3b of the split mold 31, a deep groove-shaped reinforcing rib forming portion 26 for dividing a central portion into a cross is formed. Both end portions are formed so as to be continuous with the reinforcing rib forming half portion 27. As a result, there are four bulging portions 28 between the reinforcing rib forming half portion 27 and the reinforcing rib forming portion 26.
have.

The reinforcing ribs 17 formed by these components
Are connected to the reinforcing ribs 17 formed by the mold body 32 while smoothly changing the width dimension thereof to form the integral reinforcing ribs 17.

The reinforcing rib forming half 26 of the split mold 31 is used.
The present invention can be carried out without necessarily forming the reinforcing rib forming portions 26 so as to intersect in the product forming portion 3b surrounded by.

For example, one reinforcing rib forming portion is provided at the center of the product forming portion 3b surrounded by the reinforcing rib forming half portion 26 in a plan view, and two bulging portions are formed in the shape of a "sun". Alternatively, two reinforcing rib forming portions may be provided substantially in parallel, and three bulging portions may be formed in the shape of an “eye”. Further, the product forming portion 3b surrounded by the reinforcing rib forming half portion 26 may not be provided with the reinforcing rib forming portion and may form a single bulging portion.

The split die 31 has a piston rod 34a extending downward from a hydraulic cylinder 34 provided on the upper surface of the movable platen 6 through the movable platen 6 and the upper die mounting plate. Are connected to the upper surface side.

Therefore, when the movable platen 6 is operated while the hydraulic cylinder 34 is maintained without being extended or contracted, the split mold 31 and the split main body 32 of the upper mold 3 are separated from each other. Can move up and down together.

Further, by expanding and contracting the hydraulic cylinder 34, the split mold 31 can be moved up and down as a separate body independent of the mold body 32.

The position shown in FIG. 1 of the hydraulic cylinder 34 is the position of the extension end of the hydraulic cylinder 34, and only the reducing operation for raising the split mold 31 is possible. As shown in the imaginary line on the back of the split mold 31, the stroke of the reduction operation is, for example, about 2 to 5 mm.

In the production of the casting 16 by using the mold 2 as described above, after the cavity 15 is filled with the molten metal by gravity and solidified, the movable platen 6 is raised and the mold body 32 of the upper mold 3 is raised. Prior to the mold release, the hydraulic cylinder 34 is driven to contract and the split mold 31 is raised by a few mm, so that the width dimension of the reinforcing rib 17 is large and the portion formed by the split mold 31 is removed from the casting 16. The split mold 31 is peeled off.

At this time, since the other part of the casting 16 is firmly held between the mold body 32 of the upper mold 3 and the lower mold 4, it is possible to surely peel off the split mold 31 having a large width. Therefore, there is no possibility that other parts of the casting 16 may be damaged due to the separation of the split mold 31.

In this embodiment, a boss hole 35 having a large depth is formed near the reinforcing rib 17 formed by the split mold 31 at the same time.

In this embodiment, the boss holes 3
5, the insert pin 36 installed on the mold body 32 of the upper mold 3 and the hydraulic cylinder 37 supported by the lower mold 4.
And a movable pin 38 which can be retracted by using the movable pin 38 before the mold body 32 of the upper mold 3 is released from the casting 16 when the boss hole 35 is formed. I have.

Thereafter, the casting 16 is released from the lower die 4 by raising the movable platen 6, and the casting 16 is released from the die body 32 of the upper die 3 by the projection of a knockout pin (not shown) accompanying the rise. By doing so, a casting 16 separated from the mold 2 can be obtained.

Since such a release method is used, a portion of the casting 16 having high release resistance is previously released as the split die 31 in the casting 16 as described above.
The mold release from the mold body 32 can be easily performed, and the thin and long casting 16 can be prevented from being damaged due to difficulty in releasing, and mass production of the long and thin casting can be performed.

The invention of the present application is not limited to the gravity casting method described above, and it is needless to say that the invention can be applied in a similar manner to a case where a low-pressure molten metal is supplied to the cavity 15 as in a low-pressure casting method. Nor.

[0043]

As described above, according to the first aspect of the present invention, the portion forming the portion of the cavity surface which is surrounded by the reinforcing ribs of the casting is defined by the mold body of the permanent mold. It is formed as a separate split mold, and the split mold is released before the mold body, and then the mold body is released.

That is, the split mold that forms the reinforcing rib portion to which the casting is firmly adhered by solidification of the molten metal in the cavity is released from the casting prior to the release of the entire casting, and the other portions of the casting are then removed. Since the upper mold and the lower mold are securely held, the release force of the split mold acts intensively on the reinforcing ribs to ensure the release of the reinforcing ribs and release of the split molds. There is less risk that the thin casting will be damaged by the force not acting on other parts.

Therefore, it is possible to mass-produce a long thin casting.

According to the second aspect of the present invention, the adhesion of the reinforcing rib formed by the reinforcing rib forming portion of the split mold to the mold surface is eliminated prior to the mold body by releasing the split mold. Therefore, the resistance of releasing the long thin casting from the mold body is reduced, and the release becomes easier.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line AA of FIG.

FIG. 2 is a front view of the casting apparatus.

FIG. 3 is a side view of the casting apparatus.

FIG. 4 is a plan view of the upper die.

FIG. 5 is an enlarged plan view of a main part of a product forming section of the upper die.

[Explanation of symbols]

 2 Mold (permanent mold) 3 Upper mold (permanent mold) 3b Product forming part (mold surface) 15 Cavity 16 Casting 17 Reinforcement rib 26 Reinforcement rib molding part 27 Reinforcement rib molding half part 29 Reinforcement rib molding half part 31 Split mold 32 Mold body

Claims (2)

[Claims] 1. A method for producing a thin casting by pouring a low-pressure molten metal into a cavity of a permanent mold, wherein a portion of a mold surface of the cavity, which forms a portion surrounded by reinforcing ribs of the casting, is permanently formed. A method for producing a long thin-walled casting, comprising forming a separate mold separate from a mold body of a mold, releasing the divided mold prior to the mold body, and then releasing the mold body. 2. The method of manufacturing a long thin casting according to claim 1, wherein a groove-shaped reinforcing rib is formed on the mold surface of the divided mold by a mold surface of a mold body adjacent to the periphery of the divided mold. And a groove-shaped reinforcing rib forming portion communicating between opposing portions of the reinforcing rib forming half on the mold surface of the split mold while having a reinforcing rib forming half that forms the portion over the entire circumference of the split mold. A method for producing a long thin-walled casting, comprising: