KR100271871B1 - Mold for casting of crankshaft - Google Patents

Abstract

PURPOSE: A mould structure for casting crank shaft of automobiles by using evaporation pattern casting method is provided to produce machine parts requiring superior mechanical/clear processed-surface properties by installing both a trap along runner to capture inclusions and a dam to reduce the speed of molten metal. CONSTITUTION: A plurality of pocket (3) are formed at the upper part of runner (2) to capture inclusions traveling through the runner and a dam (4) is installed at the bottom part of the runner. Such runners are installed at right front part of in-gate (5) and a joint part between an injector (1) and the runner respectively. Also, the cross-sectional view of the runner is controlled to be 1x1.5 in the ratio of length and breadth for increasing capture capacity of the pocket without changing tapping hole size.

Description

Casting structure for manufacturing crankshaft of automobile by vanishing model casting method

The present invention relates to a casting structure for manufacturing a crankshaft of an automobile by the vanishing model casting method, and more particularly, to reduce the flow rate in a pocket part and a molten metal which can trap inclusions in a runner part of a ball type system in a vanishing model casting. By forming dams that can be used to produce products that require excellent mechanical properties, such as crankshafts of automobiles, or require clean processing surfaces, the quality of the products can be increased, as well as the cost of production can be reduced.

Products with a large number of hollow parts, such as crank shafts hollowed out for the purpose of lightening automobiles, require a lot of complicated cores to be produced by the general sand mold or shell mold method. Therefore, when it is produced by Evaporative pattern casting (hereinafter referred to as EPC), there is an effect of reducing the production cost and productivity by eliminating the middle core.

However, in the case of products requiring excellent mechanical properties such as crank shafts, the inflow inclusions must be removed to make the processing surface very clean, but the method for filtering inflow inclusions is very complicated due to the characteristics of the EPC method.

That is, in the EPC method, the structure is complicated by using a stopper at a filter, a strainer or an inlet, or a trap and a dam for removing the inclusions in the runner to remove the inclusions. This was accompanied.

Therefore, the EPC method is only applied to the production of simple mold castings or castings for which the mechanical use is not large. When the EPC method is used to produce parts that require excellent mechanical properties, such as automotive crankshafts, or require clean processing surfaces, A defect such as a large number of inclusions in the substrate was not used.

An object of the present invention is to solve such a problem, to form a pocket to capture the inclusions in the runner portion of the ball system and a dam to reduce the flow rate in the molten metal in the runner system in the EPC By suppressing it, it is possible to cast products that require excellent mechanical properties such as crankshafts of automobiles or clean processing surfaces, thereby improving the quality of the products and reducing the production cost, thereby reducing the price. The present invention provides a casting structure for manufacturing a crankshaft of an automobile.

1 is a front view showing the structure of the casting according to the present invention

Figure 2 is a side view showing the structure of the casting according to the present invention

Figure 3 is a plan view showing the structure of the casting according to the present invention

-Explanation of symbols for the main parts of the drawing-

1-Inlet 2-Runner

3-Pocket 4-Dam

5-ingate

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show a front view, a side view and a plan view showing the structure of the casting according to the present invention. As shown, the basic shape of the EPC type ball system is to be able to cast two hollow crankshafts in a single type ball system. The hollow crankshaft 6 model is placed horizontally in the flask, and the position of the ingate 5 is installed at both ends of the runner 2 so that the weight balances 7 on both sides of the crankshaft 6 are fixed. ), The injection port 1 is made of a heat insulating material, and the shape is a hollow one-piece.

In addition, a plurality of inclusion trap traps 3 are formed in the upper portion of the runner 2 to capture the inclusions of the molten metal flowing in the runner 2, and a dam 4 in the lower portion of the runner 2. Is formed. Such a dam 4 is formed in the front part of the ingate 5 which is the end part of the runner 2, and in the part which leads to the runner 2 from the injection port 1, respectively. In addition, the cross section of the runner 2 described above has a ratio of width: length of the runner 2 to 1: 1.5 so that the effect of trapping the inclusions in the pocket 3 can be enhanced without changing the pouring ratio.

In the present invention as described above, the inclusions flowing in cast iron generally have a property of floating because the specific gravity is smaller than that of the molten metal. In addition, since the molten metal injected by the EPC method proceeds while pyrolyzing the model, the melter flow rate is considerably slower than that of other cavity castings, and is more likely to proceed to distillation. The effect can be maximized by being able to capture well with the pocket 3 formed in the upper part of (2).

In addition, the runner (2) formed dam (4) is to induce the injury of the inclusion by causing a decrease in the melt flow rate. The inclusions that are not filtered out of the runner 2 may not be introduced by the dam 4 formed in front of the ingate 5 so as not to enter the product portion.

As can be seen from the above description, according to the casting structure for manufacturing a crankshaft of an automobile according to the burnout model casting method of the present invention, in the EPC, the pockets and dams are formed on the upper and lower portions of the runner part of the ball type system to suppress the inflow of inclusions. It is possible to cast a product that requires excellent mechanical properties such as crankshaft or clean processing surface, thereby improving the quality of the product and reducing the production cost.

Claims (2)

Runners 2 are formed at both sides of the inlet 8 in communication with the inlet 8, and in-gates 5 are formed at both ends of the runner 2 so that the balance weight of the hollow crankshaft master 6 is formed. In the mold for casting of the crankshaft in which the molten metal is connected to the 7 and the molten metal is introduced into the model 6 of the hollow crankshaft through the hot water hole 1, the runner 2, and the ingate 5, The upper part of the runner 2 is formed with a plurality of trap pockets (3) for trapping the inclusions of the molten metal flowing in, the lower portion of the runner (2) to form a dam (4) C) is a casting mold for a crankshaft, characterized in that formed in the front portion of the ingate (5), which is the end of the runner (2), and in the portion leading from the mouth opening (1) to the runner (2). The mold for crankshaft casting according to claim 1, wherein the cross section of the runner (2) is formed with a width to height ratio of 1.5: 1 so as to increase the effect of trapping the inclusions in the pocket (3).

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