JPH04266447A - Sprue shape of mold - Google Patents

Abstract

PURPOSE:To pour a molten metal for short time and to eliminate the need for a special treatment at the time of a reusing returned cast iron by forming a sprue shape to a recessed shape and providing an upper end opening hole part of at least two downsprues and the hill type raising-up part of the opening hole part. CONSTITUTION:By pouring the molten metal into one position of the sprue 9, the molten metal can be filled up into a green sand mold through two down sprues 6. By this method, the pouring of the molten metal can be executed for short time and the down sprue 6 and runners 7 can be in slender and the returning cast iron formed in the sprue 9 is made to form two lumps. The returning cast iron connected as one piece formed in the sprue 9, down sprue 6, runners 7 and feeder head part 8 is made to two pieces of small low rigidity combined bodies. Therefore, the special treatment of taking-out of casting with shaking out machine, etc., can be eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sprue shape that facilitates the reuse of return pig iron formed in a mold sprue, down sprues and runners connected thereto.

[0002] When producing relatively small cast products such as automobile parts, a green mold as shown in FIG. 5 is conventionally used as a mold. In the figure, 1 and 2 indicate upper and lower flasks, and 3 and 4 indicate upper and lower molds that are formed in the upper and lower flasks 1 and 2, respectively, and then are combined together to form a green mold,
In the upper part of the upper mold 3 of this green mold, only one concave sprue 5 is formed where the molten metal collects, and the upper end opening of the down sprue 6 is located at the almost flat bottom 5a of the sprue 5.
The lower end opening of the down sprue 6 is connected to the upper mold 3 and the lower mold 4.
It communicates with a large number of riser parts 8 formed in the upper mold 3 through branch-like runners 7 formed along the mating surfaces thereof, and each riser part 8 is connected to Each of them communicates with a number of formed product casting cavities (not shown).

0003

[Problems to be Solved by the Invention] In recent years, the dimensions of the casting flasks 1 and 2 have become larger due to an increase in the number of products produced in one mold. In the green mold, as the sprue 5 becomes larger, the down sprue 6 and the runner 7 also become thicker to prevent cooling of the molten metal, and the runner 7 as a whole becomes larger and the connection formed within them becomes thicker. The returned pig iron becomes a large and strong bond that cannot be separated naturally when it is disassembled using a shake-out machine, etc., and if it is reused, it will get caught in the cupola and cause hanging. Processing such as cutting, fusing, or crushing is particularly required, which poses a problem of increasing processing costs.

In order to solve this problem, as shown in FIG. 6, sprues 5 are provided at two locations above the upper mold 3 of the green mold.
By providing the down sprue 6 and the runner 7 respectively, the down sprue 6 and the runner 7 can be made thinner and can be divided into two, so that the continuous return pig iron formed therein can be divided into two small pieces. A method of forming a low-rigidity bonded body has also been adopted, but in this case, it becomes necessary to pour the metal twice per mold, and there are other problems such as the time required for pouring becomes long. there were.

[0005]

[Means for Solving the Problems] It is an object of the present invention to provide a sprue shape that advantageously solves the above problems.The sprue shape of the mold of the present invention has a concave shape in which molten metal collects. , the bottom of which is provided with upper end openings of at least two down sprues and a chevron-shaped raised portion located between the openings and partitioning the bottom.

[0006]

[Operation] With such a sprue shape, when molten metal is poured into the mountain-shaped bulge at the bottom of the sprue, the molten metal is divided by the bulge and flows toward the upper end opening of each down sprue, and from those openings. Each product casting cavity is filled through each down sprue and runner.

Therefore, according to the sprue shape of the present invention, by pouring the molten metal into one sprue, the molten metal can be filled into the mold through at least two down sprues, and therefore the molten metal can be poured in a short time. Because these down sprues and runners can be narrowed, the continuous return iron formed in the sprue, down sprue, runners, etc. becomes at least two small, low-rigidity bonds during demolding. Since they are naturally separated, no special treatment is required when reusing the return pig iron.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below in detail with reference to the drawings. FIG. 1(a) is a plan view showing an example of the sprue shape of the mold of the present invention, and FIG.
FIG. 2 is a sectional view taken from the direction of arrow A, and in the figure, parts similar to those of the conventional example are designated by the same reference numerals.

In other words, 1 and 2 in the figure are upper and lower flasks, 3 and 4 are
1 and 2 respectively indicate upper and lower molds that are formed in the upper and lower casting flasks 1 and 2 and then combined with each other to form a green mold, and the upper mold 3 of the green mold has a concave sprue in the upper part where the molten metal collects. 9 has a top runner shape that extends to some extent in the longitudinal direction of the green mold, and is formed only in one place near the upper flask 1, and near both ends of the bottom 9a of the sprue 9, Two down sprues 6 which are the channels for molten metal
The upper end openings are located respectively, and the lower end openings of these down sprues 6 are connected through branch-like runners 7 that are divided into two systems and formed along the mating surface of the upper mold 3 and the lower mold 4. It communicates with a large number of feeder parts 8 formed within the upper mold 3, and each riser part 8 communicates with a large number of product casting cavities (not shown) formed within the green mold.

As is clear from FIGS. 1(a) and 1(b), the bottom 9a of the sprue 9 has a structure between the upper end openings of the two down sprues 6 formed in the bottom 9a. A mountain-shaped raised portion 9b having a height approximately half the depth of the sprue 9 is formed, which is positioned to partition the bottom portion 9a into two.

[0011] With such a sprue shape, when pouring molten metal using an automatic pouring device, by appropriately adjusting the pouring amount and speed, the sprue 9 can be closed during pouring as shown in FIG. 2(a). If you pour molten metal 10 so that it is full,
It is possible to pour molten metal into each riser part 8 and each product casting cavity through two systems of runners 7 from the two down sprues 6 in a short time while making the riser sufficiently effective, and when the pouring is finished, As shown in FIG. 2(b), if the molten metal 10 is poured so that the surface height is less than half the depth of the sprue 9, the molten metal remaining in the sprue 9 will be The molten metal 10 is cooled and solidified in the sprue 9, and the returned pig iron is formed into two small lumps.

Therefore, according to the sprue shape of this embodiment, the molten metal 10 can be filled into the green mold through the two down sprues 6 by pouring the molten metal 10 into the sprue 9 at one location, so that the mold can be filled in a short time. Pouring can be carried out, and the down sprue 6 and runner 7 can be made thin, and the return pig iron formed in the sprue 9 becomes two small lumps. Road 7 and hot spring section 8
The continuous return pig iron that is formed in the process becomes two small, low-rigidity joints, which are naturally separated when demolded using a shake-out machine, etc., so there is a special problem when reusing the return pig iron. Processing can be made unnecessary.

On the other hand, FIG. 3(a) is a plan view showing another embodiment of the sprue shape of the mold according to the present invention, and FIG. 3(b) is a sectional view taken from the direction of arrow B in FIG. 3(a). In this example, the sprue 11 is formed in a T-shaped top runner shape, and the horizontal bar part 11a of the bottom part is located in the center of the green mold, and the end part of the vertical bar part 11b is located in the upper flask. The upper end openings of two down sprues 6 are located near both ends of the horizontal bar 11a, and the lower end openings of these down sprues 6 are divided into two systems. The formed branch-like runners 7 communicate with a large number of riser parts 8 formed in the upper mold 3, and each riser part 8 communicates with a large number of riser parts 8 (not shown) formed in the green mold. Each communicates with the product casting cavity.

As shown in FIG. 4(a), the vertical bar portion 11b of the bottom of the sprue 11 is shallower than the horizontal bar portion 11a, and is inclined toward the horizontal bar portion 11a. , and the horizontal bar portion 11a is shown in FIG. 4(a).
, (b), the vertical bar part 11b is located between the upper end openings of the two down sprues 6 formed on the horizontal bar part 11a and partitions the horizontal bar part 11a into two parts.
A chevron-shaped raised portion 11c is formed which is inclined toward the top.

According to the sprue shape of this embodiment, the sprue 1
By pouring the molten metal from the end of the vertical bar part 11b of No. 1, the molten metal flows from the vertical bar part 11b to the horizontal bar part 11a and is divided at the raised part 11c without impairing the ease of pouring. Since the metal can be poured into the green mold from the two down sprues 6 near the part, in addition to the same effect as in the previous embodiment, the time required to pour metal into a large number of product casting cavities can be equalized, and the pouring time can be reduced. A further reduction in time and a more uniform quality of the cast product can be achieved.

Although the above has been explained based on the illustrated example, the present invention is not limited to the above-mentioned example. For example, the upper end openings of three or more down sprues are provided at the bottom of the sprue, and A chevron-shaped raised portion may be formed in between. Furthermore, the sprue shape of the present invention can be applied not only to green molds but also to coated molds formed by the lost wax method.

[0017]

[Effects of the Invention] Thus, according to the sprue shape of the mold of the present invention, by pouring the molten metal into the sprue at one location, the molten metal can be filled into the mold through at least two down sprues in a short time. Because the downsprues and runners can be poured and their downsprues and runners can be narrowed, the continuous return pig iron formed in the sprues, downsprues, runners, etc. becomes at least two small, low-rigidity connections. hand,
They are naturally separated during demolding, which eliminates the need for special treatment when reusing return pig iron.

[Brief explanation of the drawing]

FIG. 1(a) is a plan view showing an example of the sprue shape of a mold according to the present invention, and FIG. 1(b) is a sectional view taken from the direction of arrow A in FIG. 1(a).

FIG. 2(a) is an explanatory diagram showing the state of the sprue in the above embodiment during pouring, and FIG. 2(b) is an explanatory diagram showing the state of the sprue at the end of pouring.

FIG. 3(a) is a plan view showing another embodiment of the sprue shape of the mold according to the present invention, and FIG. 3(b) is a sectional view taken from the direction of arrow B in FIG. 3(a).

4(a) is a sectional view taken from the direction of arrow C in FIG. 3(a), and FIG. 4(b) is a sectional view taken from the direction of arrow D of FIG. 3(a).

5(a) is a plan view showing an example of the sprue shape of a conventional mold, and FIG. 5(b) is a sectional view taken from the direction of arrow E in FIG. 5(a).

6(a) is a plan view showing another example of the sprue shape of a conventional mold, and FIG. 6(b) is a sectional view viewed from the direction of arrow F in FIG. 6(a).

[Explanation of symbols]

1 Upper casting flask 2 Lower flask 3 Upper mold 4 Lower mold 6 Down sprue 7 Hot water path 8　Rice bath section 9 Sprue 9a Bottom 9b Swelling part 10 Molten metal 11 Sprue 11a Horizontal bar part 11b Vertical bar part 11c Swelling part

Claims (1)

[Claims] Claim 1: It has a concave shape in which molten metal collects, and its bottom (9a) is provided with upper end openings of at least two down sprues (6) and a chevron located between these openings to partition the bottom. The mold sprue shape includes a raised part (9b).