JPH01104454A - Method and apparatus for casting thin cast product - Google Patents

Abstract

PURPOSE:To execute good running of molten metal and to improve dimensional accuracy of thickness by enlarging narrow cavity to fill up the molten metal, next reducing the cavity to thin product-like and flowing the excess molten metal into an adjoining overflow cavity. CONSTITUTION:An advancing/retreating device 4 is retreated and a thickness adjusting insert 6 is full-backed and a thickness adjusting cavity 8 is beforehand enlarged to thickness T1 and the molten metal is filled up into the cavities 7, 8 by a plunger tip 9. Under condition of impressing pushing force with the plunger tip 9, the advancing/retreating device 4 is advanced and an advancing/ retreating device 13 is retreated and by retreating an opening/closing pin 15, a well is opened, and the cavity 7 and the overflow cavity 12 are communicated, and the molten metal is flowed into a cavity 12 caused to impress the pressure. The thickness adjusting insert 6 is held to advancing condition to the full stroke and as the plunger tip 9 impresses the pushing force, the molten metal is surely run even to the fine part, to shape the thin cast product.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to the technical field of manufacturing thin-walled metal casting products such as automobile parts.

Therefore, the invention of this application fills a predetermined amount of hot water with a plunger tip through a cavity gate provided in a fixed mold and whose volume is variable from thick to thin, and the mold is opened by solidification of the molten metal. This invention relates to a method of casting a thin-walled casting using a mold, and an apparatus used directly in the method, and particularly a state in which a cavity formed in a fixed mold is enlarged by enlarging the cavity with a wall thickness adjusting insert. The cavity is filled with molten metal using a plunger tip, and then the cavity is reduced to a thin product shape by advancing the wall thickness adjusting insert, and the excess molten metal at this time is formed in an overflow cavity adjacent to the cavity at a connection portion from the cavity. This invention relates to a method and a casting apparatus for casting a thin die-cast product by opening an opening/closing pin to allow the flow to flow into a well.

<Prior art> As is well known, many products such as mechanical devices! Many of the products are cast using 8-casting method, and among these, die casting method is used to accurately cast products with complex shapes according to the design.
High-pressure die casting is widely used.

In this case, there are various problems such as the fact that the gate that fills the cavity with molten metal has a small cross-sectional area.

That is, for example, 1000 to 120 at a high speed of 2 to 4 m/s.
Filling with a high pressure of 0KI f/cM, adjusting the flow direction of the molten metal by devising a method, reducing the pressure inside the cavity to reduce the back pressure of gas in the cavity, or adjusting the temperature of the molten metal. A method of casting at a temperature of 660 to 720°C has been adopted, but as mentioned above, since the molten metal flows into the cavity through the gate with a narrow cross section, the flow of the molten metal in the cavity is limited to the product. The problem is that it is limited by the shape, and in a cavity where thick and thin parts coexist, the flow resistance of the molten metal is unbalanced and the difference in wall thickness is 4F.
In cases where M1 or more, there is a drawback that a thin wall portion of 3.5 seconds or less causes poor water circulation.

Additionally, in low-pressure casting or gravity casting, there are methods in which the temperature of the molten metal is increased, for example, 700 to 800°C for aluminum, or the temperature of a fixed mold or a movable mold is raised and filled with molten metal, but there are similar problems. .

There is also a method of suction casting, in which molten metal is filled into a cavity from a heat-retaining furnace through negative pressure, but casting by this method cannot avoid the same problems.

For example, in ultra-thin castings with a thickness of 1.5 s or less, even if the product shape is uniform, there is a problem that poor molten metal circulation occurs, and the space in the cavity into which the molten metal flows when filling is It has the disadvantage that it is as narrow as the thickness, and that poor flow occurs due to the fluidity of the molten metal being inhibited by the frictional force caused by the contact between the molten metal and the mold.

In addition, in the high-pressure die-casting method, the cooling rate of the molten metal is fast, so it is necessary to raise the temperature of the molten metal, which has the disadvantage of poor energy efficiency. need to be,
This also has the disadvantage of high energy costs.

Another method is to fill the mold with molten metal in an open state and then close the model, but since the molten metal leaks when filling the mold, the opening amount of the mold has to be as small as 0.1 to 1M, and the molten metal There was a negative point that the thickness of the product was not accurate due to variations in the filling process.

Therefore, for example, the applicant's earlier invention, JP-A-55-
68165@Publication invention etc., but since the molten metal from the gate flows into the cavity in a layered manner at a relatively low speed, gas entrainment does not occur, and there are few casting defects such as gas holes and shrinkage cavities, resulting in a sound casting method. There is also the advantage that a product can be obtained, and since the effective cross-sectional area of the cavity is small, there is an advantage that the cavity part of the product can be easily cut.

However, in the nuclide prior art, since the gate part is a twin type, the structure in the narrow gate part is complicated, the manufacturing cost is high, and maintenance, inspection, etc. are complicated.

Therefore, in the technique of the applicant, for example, as shown in FIG.
The advancing/retracting device 4 is moved back and the wall thickness adjusting insert 6 is moved back by the back stroke via the coupling 5 to form a wall thickness adjusting cavity 8 in the cavity 7, and the plunger tip 4 sufficiently flows the molten metal through the gate 10. After a predetermined period of time, the advancing/retracting device 4 is advanced to move the wall thickness adjustment insert 6 forward by a full stroke, and the plunger tip 9 is moved back by a considerable amount to open the wall thickness adjustment cavity 8. A method has also been devised in which thin wall casting is performed by returning the molten metal to the plunger part to maintain a pressurized state, but in this casting method, there are times when the pressurizing force to the filled molten metal does not work. There are defects that are likely to cause casting defects such as distortion due to solidification shrinkage, cracks, and blowholes, and the injection control of die casting machines is complicated and its management is cumbersome. In order to improve post-processing problems such as cutting and removing parts, the gate part filled with molten metal must be made as thin as 2 to 8M. The problem was that it was difficult for the adjustment insert to advance a full stroke, and the accuracy of the product's original wall thickness was poor.

The purpose of the invention of this application is to enable smooth filling of molten metal into cavities in which both thick and thin parts coexist based on the above-mentioned prior art, to allow good molten metal circulation, and to maintain the shape of the product even in thin parts. Uniformity ensures sufficient fluidity of the molten metal, it does not require much thermal energy, there is no variation in charging IR, it has good post-processing properties such as cutting and removing cavities, and the dimensional accuracy of the product wall thickness is good. It is an object of the present invention to provide an excellent method and apparatus for casting thin-walled castings, which will benefit the field of application of casting technology in the machine manufacturing industry.

<Means/effects for solving the problem> In accordance with the above-mentioned object, the structure of the invention of this application, which is based on the scope of the above-mentioned patent claims, is to solve the above-mentioned problem by casting a cast product having a thin wall part. When this is done, the wall thickness adjustment insert of the fixed mold cavity facing the movable mold is made a full back stroke using its advancement/retraction device, the thickness adjustment cavity is added to the cavity to enlarge it, and the molten metal is poured through the plunger tip. Filling is performed by the gate, and then the wall thickness adjustment insert is advanced to reduce the cavity by the amount of the wall thickness adjustment cavity to suppress the filled molten metal, and the opening/closing pin of the well is passed through the well into the overflow cavity adjacent to the cavity. Open by retreating and press filling, maintain a predetermined pressing force and solidify to form a thin-walled casting, open the fixed mold and movable mold to take out the thin-walled casting, and easily cut the gate part. Technical measures have been taken to remove this.

<Example> Next, an example of the invention of this application will be described below with reference to FIG. Note that the same parts as in FIG. 2 will be explained using the same reference numerals.

In the embodiment shown in FIG. 1, the illustrated casting mold is a thin-walled casting device that forms the center of one of the gist of the invention of this application,
The fixed mold 1 is installed opposite to a movable mold 3 that is fixed and supported by a support 2, and a wall thickness adjustment device 4 such as a hydraulic cylinder provided at the rear end is connected to the movable mold 3 through a coupling 5. An insert 6 is provided, and a cavity 7 with a crotch thickness T is provided.
On the other hand, a wall thickness adjustment cavity 8 is formed with a wall thickness of T1 for a full back and T2 for a full stroke, and a plunger tip 9 is connected to a predetermined advance/retreat device in the lower part, so that it can freely advance and retreat for a predetermined stroke. The plunger is connected to the cavity 7 through the gate 10.

Further, an overflow cavity 12 is formed in the upper part of the cavity 7 through a well 11 so as to be opposed to the movable mold 3. An opening/closing pin 15 is provided via a coupling 14 to the advancing/retracting device @ 13 of a hydraulic cylinder, etc., and the cavity 7
The overflow cavity 12 can be opened and closed.

When casting a thin-walled casting in the above-mentioned thin-walled casting apparatus, first, the advancement/retraction device 4 is moved back to fully back the wall thickness adjustment insert 6 via the coupling 5, and the thickness adjustment cavity 8 is moved to T1. Then, the plunger depth 9 passes the molten metal through the gate 10 into the cavity 7 and the enlarged wall thickness adjustment cavity 8.
Fill it.

At this time, the opening/closing pin 15 moves forward by a full stroke due to the advance of the advancing/retracting device 13 and blocks the cavity 7 and the overflow cavity 12, so the molten metal filled in the cavity 7 does not flow into the overflow cavity 12.

Then, the plunger tip 9 applies a predetermined pressing force to the molten metal filled in the cavity 7 and the wall thickness adjustment cavity 8 in a sufficient amount.

Immediately after the initial state in which the molten metal is filled into the cavity 7 and the wall thickness adjustment cavity 8 and the filling pressure is applied by the plunger tip 9, the advancement/retraction device 4 is advanced while applying the pressing force by the plunger tip 9. ring 9
The well 11 is opened by moving the wall thickness adjustment insert forward by a full stroke through the screwdriver, and retracting the advancing/retracting device 13 to retract the opening/closing pin 15 through the coupling 14, and the cavity 7 and the overflow cavity 12 are brought into communication. As a result, the molten metal, which is under pressure due to the pressing force of the plunger tip 9 and the wall thickness adjustment insert 6, flows into the well 11.
The air flows into the overflow cavity 12 through the air and pressure is applied thereto.

Therefore, the wall thickness adjustment insert 6 maintains the full stroke forward state, and the molten metal in the cavity 7, which has been reduced to the thickness T2 in order to apply the pressing force to the plunger tip 9, is a minute portion. It spreads over the entire area, reliably fills thin-walled areas, and begins to solidify.

In this way, a thin-walled casting product is formed.

Therefore, the volume of the overflow cavity 12 is equal to the sum of the volumes of the overflow cavity 12 and the well 11 so that the wall thickness adjustment insert 6 can move forward with a complete full stroke and maintain the original thickness T2 of the cavity. The volume of the wall thickness adjustment cavity 18 is set in advance to be equal to or larger than that, and the pressing force of the advancing/retracting devices 4 and 13 is set approximately 10% higher than the pressing force of the plunger tip 9 against the molten metal. The molten metal flows into the overflow cavity 12 from 7 through the well 11, and the molten metal is made to spread over the thin walled portion of the cavity 7.

Then, the advancing/retracting device 13 is advanced and the opening/closing pin 1 is moved forward.
By advancing the molten metal 5 and pressing the molten metal in the well 11, the molten metal is more reliably filled into the thin walled portion of the cavity 7 having a thickness of T2, and an accurate thin-walled casting as designed is manufactured.

After the casting has been cooled and solidified, the movable mold 3 and the fixed mold 1 are opened, the thin-walled casting is taken out, and the gate portion is cut and removed to obtain a predetermined thin-walled casting product.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments, and various embodiments can be adopted, such as interposing an elastic spring with a predetermined spring constant in the wall thickness adjustment insert or the opening/closing pin. It is.

The present invention can be applied not only to metal products but also to resin molded products.

<Effects of the Invention> As described above, according to the invention of this application, when casting thin-walled automobile parts, etc., the thickness-adjusting insert is inserted into the thin-walled cavity so that it can move forward and backward, and the thickness-adjusting cavity is made into a cavity of a predetermined capacity. By making it possible to enlarge or reduce the cavity, when filling the initial molten metal, the wall thickness adjustment insert is moved back, the thickness adjustment cavity is added to the cavity, the cavity is enlarged, and the molten metal is filled with the plunger tip. At the same time as pressure is applied by the plunger tip, the wall thickness adjustment insert is pressed to open the opening/closing pin, and the excess molten metal flows out through the well into the overflow cavity adjacent to the cavity.
This is an excellent method in that it is possible to reliably form a casting with a predetermined thin wall by making the cavity a predetermined thin-walled molten metal, moving the opening/closing pin forward to isolate the cavity and the overflow cavity, and applying pressing force to the thin-walled molten metal with the plunger tip. The effect is produced.

Also, by pressing the opening/closing pin at the timing to cause the molten metal in the cavity to flow out into the overflow cavity,
Combined with the pressing force, the plunger tip for the cavity can more reliably apply high-pressure pressing force to the thin-walled castings in the cavity, filling even the smallest parts of the thin-walled metal with molten metal, resulting in accurate and precise thin-walled castings. The excellent effect of

Therefore, when the cavity is filled with molten metal, the contact resistance between the molten metal and the cavity can be reduced and made uniform because the wall thickness adjustment cavity is added to the cavity. The effect of being able to smoothly fill the interior with molten metal is achieved.

In addition, in order to fill the excess molten metal into the cavity (immediately after filling the molten metal with the thickness adjusting insert), the thickness adjusting insert is advanced to ensure that the molten metal of the thin-walled casting is filled as expected. It has the advantage that it can be filled under pressure.

In addition, the opening/closing pin blocks the cavity and the overflow cavity via the well, making it freely openable and closable, so that when the cavity initially expanded by the plunger tip is filled with molten metal, the opening/closing pin blocks the well and prevents the filled molten metal from overflowing. It also has the effect of preventing it from flowing into the cavity.

Since the cavity is provided with a wall thickness adjustment insert that can move forward and backward, the volume of the cavity can be expanded and contracted, so initially enough molten metal is filled into the cavity, and then, In order to allow excess molten metal, which is more than enough molten metal for thin-walled castings, to flow out into the overflow cavity by advancing the wall thickness adjustment insert, it is ensured that sufficient molten metal for thin-walled castings is filled into the reduced cavity in the second stage. This has the excellent effect of allowing sufficient hot water circulation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an apparatus according to an embodiment of the invention of this application, and FIG. 2 is a sectional view of a die of a thin-wall casting apparatus based on the prior art. 7... Cavity, 10... Gate, 9... Plunger chip, 1. ... Fixed type, 3... Movable type, 6... Thickness adjustment insert, 12... Overflow cavity, 11... Well, 15... Opening/closing pin 1 Figure 7-10-σ Child 1 Toke 1 Hi 9--Prancey Syria 1-1 fixed! 13---Movable alliance 6-e town (5)! λ÷12−7−n−
Froniya Goti 11-1 Wajire + 5- = tjl key Figure 2 □ Written amendment to the procedure dated 22nd of the Showa period Kunio Ogawa, Commissioner of the Japan Patent Office 1, Indication of Case Patent Application No. 1982-261793 2, Invention Name Casting method and apparatus for thin-walled castings 3, Relationship with the case of the person making the amendment Patent applicant address 1 Toyota-cho, Soda City, Aichi Prefecture Name (320) Representative of Toyota Motor Corporation
Kiyoshi Matsumoto 4, Agent 105 Address 1-19-3-6 Nishi-Shinbashi, Minato-ku, Tokyo Number of inventions increased by amendment None, -1 number 2.
Insert.

Claims (2)

[Claims] (1) In a method of casting thin-walled castings by filling a variable capacity cavity with molten metal through a gate, the narrow cavity is first expanded and filled with molten metal, then the cavity is reduced to a thin-walled product, and the excess molten metal is poured into the cavity. A method for casting thin-walled castings, characterized in that the flow is caused to flow into adjacently connected overflow cavities. (2) In a casting device for thin-walled castings having a fixed mold having a plunger connected to a variable capacity cavity and a movable mold installed opposite to the fixed mold, a wall thickness adjusting insert is provided in the cavity connected to the advancement/retraction device. 1. A casting device for thin-walled castings, characterized in that an opening/closing pin is coupled to an advancing/retracting device and facing a well to an overflow cavity connected to the cavity.