Low-pressure casting mold for piston

Abstract

To propose a method that uses AC4A material through low-pressure casting, which allows a heat treatment, a solution treatment, and solution hardening since conventional technologies allow one die-casting mold for a piston to produce one casting, but it is not possible to set the hardness to be easy to cut.SOLUTION: Proposed is a method to produce a single piston using a low-pressure casting mold. The top mold is equipped with a water cooling mechanism that allows directional solidification and prevents shrinkage cavities. For the purpose of preventing air entrapment, the mold is designed with a gap of 0.05 mm between the top mold and the side mold, allowing the air inside to escape to the outside of the mold. AC4A material can be used, a heat treatment is possible, and solid solution hardening can be performed.

Description

[Technical field]

[0001] The present invention is a method for producing each piston using a single mold. [Background technology]

[0002] Conventionally, pistons were made by gravity casting. Since 2004, Honda Metal Technology Co., Ltd. has been able to use die casting. This time, we investigated whether there was another casting method. We made a mold for low pressure casting and tried a method of making a single piston. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Application number 2022-81943 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved is that die casting of pistons does not allow heat treatment, so materials for die casting are used. Here, pistons are made by low-pressure casting, so heat treatment is possible and the hardness can be made hard enough for cutting. The advantage is that it allows the use of AC4A, a casting material for low-pressure casting, rather than die casting materials. This material can be heat treated and the hardness can be set. It also makes cutting easier. Also, small-lot production of pistons can be done using a single-cavity mold, so it can be used even when multiple pistons are not desired. [Means for solving the problem]

[0005] A single-cavity low-pressure casting mold was designed as the mold structure. A gap of 0.05 mm was provided between the upper and side molds for low-pressure casting, and because it is low-pressure casting, the low pressure prevents molten aluminum from leaking out of the mold, and air inside the mold is not drawn in, allowing the material to be removed from the mold.

[0006] Another advantage is that, unlike large casting molds, casting can be done without providing an overflow.

[0007] Furthermore, for pinholes, which are caused by hydrogen, argon gas or nitrogen gas is passed through the molten metal to carry out a process called bubbling, which dissolves positively charged hydrogen ions into negatively charged argon gas, etc. This method involves extracting hydrogen gas from the molten metal.

[0008] The next feature is that by casting with a water cooling mechanism in the upper mold and with or without an air cooling mechanism in the lower mold, directional solidification is possible, and when aluminum solidifies during the casting process, shrinkage cavities can occur, but when the wall thickness is considered, shrinkage cavities are unlikely to occur. Low pressure casting is used. Effect of the Invention

[0009] The advantages of the invention are that heat treatment can be performed because it is low-pressure casting. In the case of die casting, air is entrapped, so if precipitation hardening is aimed at by solution treatment, the entrapped air part may swell. In the case of low-pressure casting, there is a gap between the top and side dies, so there is less entrapment of air. Heat treatment is possible, so the hardness of the piston material can be set. It is easy to cut. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 shows an overall view of low pressure casting of a piston. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the embodiment, a single cavity low pressure casting die for a piston is shown. EXAMPLES

[0012] Figure 1 shows the overall image of the low pressure casting die for the piston in this invention. A water cooling mechanism is installed on the top of the upper die for the piston material part, and the upper die is cooled. The purpose is to reduce the cycle time of casting. [Industrial Applicability]

[0013] When making pistons in small batches, we considered single-cavity low-pressure casting. Sand molds generate dust that is harmful to people, so we designed a mold that is friendly to the working environment.

[0014] Because it is a low-pressure casting, heat treatment can be performed and cutting is easy. In other words, the hardness of soft aluminum can be set, making it easier to cut.

[0015] Finally, since the upper mold is equipped with a water cooling mechanism, solidification proceeds from the upper mold to the lower mold, and the molten aluminum enters through the sprue, resulting in directional solidification that is less likely to result in shrinkage cavities. [Explanation of symbols]

[0016] 1 upper mold 2-sided type 3 lower mold 4 Upper mold water cooling mechanism 5 Intermediate stoke 6 Spout Color 7 Piston material

Claims

[Claim 1] Invention of a method using low-pressure casting molds that enables small-lot production of single-cavity pistons for automobiles and motorcycles.

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