Aluminum alloy cylinder head without riser casting mold
By using riserless casting mold design and low-pressure casting process, the problems of low grain size and low yield of cylinder head combustion chamber surface were solved, enabling efficient production of high-performance cylinder heads and reducing manufacturing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 戴少康
- Filing Date
- 2025-04-25
- Publication Date
- 2026-07-10
AI Technical Summary
In existing aluminum alloy cylinder head casting processes, low-pressure casting results in the combustion chamber surface grain size and secondary dendrite spacing of the cylinder head not meeting high-performance requirements, while gravity casting has low yield and high cost.
The design adopts a riserless casting mold, with molten aluminum fed from the cylinder head cover surface. Combined with low-pressure casting process, it utilizes negative pressure suction and water cooling mechanism to ensure low combustion chamber temperature and fast solidification. Solidification and feeding are completed by low-pressure gas, eliminating the need for riser sand core mold.
It increased the cylinder head yield to 90%, reduced manufacturing costs, ensured that the secondary dendrite spacing in the combustion chamber met high-performance requirements, and avoided porosity and shrinkage defects.
Smart Images
Figure CN224475571U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a casting mold, specifically to an aluminum alloy cylinder head casting mold. Background Technology
[0002] In recent years, with the rapid development of China's automotive industry, the technology of automotive engines and their key components has become increasingly mature, and key components (such as cylinder heads) have gradually achieved localization. With the gradual localization of cylinder heads, the traditional 90-degree tilting gravity casting process is increasingly widely used. This process utilizes a 90-degree tilting casting machine to allow molten aluminum to smoothly enter the mold cavity from the mold's sprue basin under gravity. Through filling, solidification, and cooling processes, risers are used to feed and shrink the cylinder head product, thus shaping the product. The aluminum alloy cylinder head casting molds generally include an upper mold, left end mold, right end mold, front mold, rear mold, and lower mold. The main characteristic of the 90-degree tilting gravity casting process is the use of risers to feed and shrink the product, ensuring a high yield rate, but the output rate is only about 50%. Therefore, this process suffers from serious disadvantages such as low output rate and high manufacturing cost. In addition, some companies in the industry are currently using low-pressure casting to produce cylinder heads. The basic principle of low-pressure casting is to use low-pressure gas to drive molten metal in a holding furnace, causing it to rise through a riser pipe and enter the mold cavity. After filling, low-pressure gas is used to pass through the holding furnace to allow the molten metal in the mold cavity to solidify and shrink under pressure. The main feature of this low-pressure casting process is that it utilizes the principle of low-pressure casting, and its product yield can reach about 90%. However, the main technical drawback of this process is that the aluminum liquid is filled from the combustion chamber surface of the cylinder head. During the production process, this part of the cylinder head is always under a high temperature, resulting in a larger grain size and secondary dendrite spacing on the combustion chamber surface, which cannot meet the high technical requirements of high-performance engines or range extenders for new energy vehicles. Summary of the Invention
[0003] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a riserless casting mold for aluminum alloy cylinder heads. This solves the problem that low-pressure casting cannot guarantee the secondary dendrite spacing of the cylinder head combustion chamber surface when feeding material from the cylinder head combustion chamber surface. At the same time, it can also solve the problem of low product yield caused by gravity casting through riser feeding.
[0004] The objective of this invention is achieved through the following technical solution: an aluminum alloy cylinder head riserless casting mold, comprising an upper mold, a left end mold, a right end mold, a front mold, and a rear mold. The lower part of the front mold has an inward front mold protrusion, and the lower part of the rear mold has an inward rear mold protrusion. The inward front mold protrusion and the inward rear mold protrusion are combined to form a lower mold. The upper mold, left end mold, right end mold, front mold, and rear mold are combined to form a mold cavity. The bottom of the lower mold has a communicating main runner, an inner runner, and a sprue. The sprue is sequentially connected to a transition sleeve and a riser pipe. The upper mold, left end mold, right end mold, front mold, and rear mold are respectively installed on the upper template, left template, right template, front template, and rear template.
[0005] A water cooling mechanism is installed on the outer side of the upper mold, and a negative pressure suction mechanism is installed on the outer side of the front mold.
[0006] By employing this invention, the interior of the casting mold is formed with the combustion chamber facing upwards and the cover facing downwards, corresponding to the cylinder head. The molten aluminum is fed into the mold starting from the cover surface of the cylinder head, resulting in a lower temperature and relatively faster solidification at the combustion chamber location. This leads to a smaller secondary dendrite spacing (high density) at this combustion chamber location, meeting relevant high-tech requirements. After mold closing, the casting mold forms a lower mold instead of a separate lower mold. This cylinder head casting method does not require a special riser for feeding. Instead, it relies on low-pressure gas passing through a holding furnace to allow the molten aluminum in the mold cavity to solidify and feed the cylinder head body under pressure. This not only increases the cylinder head yield to about 90%, effectively reducing the cylinder head casting manufacturing cost, but also eliminates the need to make special riser sand cores and riser sand core molds, thus significantly reducing the sand core manufacturing cost and omitting the cylinder head riser manufacturing cost. Attached Figure Description
[0007] Figure 1 This is a schematic diagram of the riserless casting mold for the aluminum alloy cylinder head of the present invention.
[0008] Figure 2 This is a process diagram of the casting method used in this invention (the cylinder head cover surface faces upwards, forming the cylinder head casting, and removing the transition sleeve).
[0009] Figure 3 This is a schematic diagram showing the disassembly of the various sand cores used in this invention. Detailed Implementation
[0010] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0011] Reference Figure 1 , Figure 2It is understood that the riserless casting mold for aluminum alloy cylinder heads of the present invention includes an upper mold 5, a left end mold 2, a right end mold 6, a front mold 8, and a rear mold 3. The lower part of the front mold 8 has an inward front mold protrusion 28, and the lower part of the rear mold 3 has an inward rear mold protrusion 23 (corresponding to the position of the inward front mold protrusion 28). The inward front mold protrusion 28 and the inward rear mold protrusion 23 are combined to form a lower mold 11 (there is no separate lower mold, that is, no special riser sand core mold is needed, and the riser sand core is omitted). The upper mold 5, the left end mold 2, the right end mold 6, the right end mold 7, the right end mold 8, the right end mold 8, the right end mold 9, the right end mold 10, the right end mold 11, the right end mold 11, the right end mold 11, the right end mold 11, the right end mold 2 ...11, the right end mold 11, the right end mold 11, the right end mold 11, the right end mold 11, the right end mold 11 2. The right end mold 6, the front mold 8, and the rear mold 3 are combined (i.e., after mold closing) to form the mold cavity 1. The bottom of the lower mold 11 has a main sprue 13, an inner sprue 12, and a sprue opening 14 (located at the bottom of the casting mold). The sprue opening 14 is connected to the transition sleeve 9 and the riser pipe 10 in sequence. The upper mold, left end mold, right end mold, front mold, and rear mold of the casting mold (metal material) are respectively installed on the upper template, left template, right template, front template, and rear template of the casting system equipment.
[0012] A water cooling mechanism 4 is installed on the outer side of the upper mold 5 (to cool the hot spot and combustion chamber of the cylinder head, avoid shrinkage casting defects in the cylinder head casting, and at the same time make the combustion chamber of the cylinder head more compact). A negative pressure suction mechanism 7 is installed on the outer side of the front mold 8 (to exhaust the gas generated by the setting of each sand core, and avoid the appearance of air holes in the cylinder head casting).
[0013] Relative to the cylinder head, the combustion chamber surface of the cylinder head faces upwards, and the cover surface faces downwards. Molten aluminum is fed into the mold starting from the cover surface. The low-pressure filling casting method used in the riserless casting mold for the aluminum alloy cylinder head is as follows: First, according to the sand core decomposition process, corresponding aluminum alloy cylinder head upper water passage sand core 16, lower water passage sand core 19, intake manifold sand core 21, small exhaust manifold sand core 18, large exhaust manifold sand core 17, oil cavity sand core 15 (and other sand cores 20, such as...) are produced. Figure 3As shown), no special riser sand core is required (i.e., no special riser sand core mold is needed). Each sand core is then placed into the riserless casting mold for the aluminum alloy cylinder head, and each sand core is pressed together by clamping mechanisms corresponding to the left mold 2, right mold 6, front mold 8, rear mold 3, and upper mold 5 (to prevent positional displacement of the sand cores during the flipping process). Next, after the casting mold is closed, it is flipped 180 degrees using a flipping mechanism, so that the combustion chamber surface of the cylinder head faces upwards and the cover surface faces downwards, and the molten aluminum begins to fill the mold from the cover surface. Then, a conveying and moving mechanism moves the flipped casting mold above the holding furnace, connecting the holding furnace with the casting mold. Then, using the low-pressure casting principle, low-pressure gas drives the molten aluminum in the holding furnace, causing... The liquid rises through the riser pipe 10 and enters the mold cavity of the casting mold for filling. Low-pressure gas is used to pass through the holding furnace to allow the aluminum liquid in the mold cavity to solidify and feed the cylinder head under pressure (i.e., pressurization and pressure holding). At the same time, during the entire liquid rising process, the negative pressure suction mechanism is activated to discharge the gas generated by the setting of each sand core, thereby avoiding porosity in the cylinder head casting. The water cooling mechanism is activated to cool the hot spot and combustion chamber of the cylinder head casting, thereby avoiding shrinkage casting defects in the cylinder head casting, and at the same time, making the combustion chamber of the cylinder head more compact (i.e., the secondary dendrite spacing in the combustion chamber reaches higher performance requirements). After depressurization, the flipping mechanism flips the casting mold 180 degrees in the opposite direction to return it to its original position, and the casting mold is opened again to remove the cylinder head casting 22.
[0014] The main gating 13 and the inner gating 12 are located at the bottom of the lower mold of the casting mold (i.e., between the lower mold and the transition sleeve). The gating opening 14 is connected in sequence to the transition sleeve 9 and the riser pipe 10. The riser pipe 10 is installed on the holding furnace and is then pressurized by a low-pressure machine, a pressurizing mechanism, and a pressurizing drive device, so that the molten aluminum in the holding furnace passes through the riser pipe 10, the transition sleeve 9, the gating opening 14, the main gating 13, and the inner gating 12 in sequence and smoothly enters the mold cavity 1 to fill the mold cavity (filling the mold cavity in a laminar flow manner to form the cylinder head casting). Figure 2As shown (in actual use, the riser pipe faces downwards). The process steps (and parameters) are as follows: liquid riser, mold filling, pressure increase and holding, and pressure release. Low-pressure gas is used to pass through the holding furnace to allow the aluminum liquid in the mold cavity to solidify and shrink under pressure (i.e., pressure increase and holding). The aluminum liquid temperature is 705±5℃, the liquid riser pressure is 20Kpa, the holding pressure is 22Kpa, the mold filling time is 22S, and the holding time is 300S. After pressure release, the flipping mechanism flips the casting mold 180 degrees in the opposite direction to return it to its original position, and the casting mold is opened again to remove the cylinder head casting (after forming the cylinder head casting product, the main gating 13, the inner gating 12, and the gating opening 14 of the cylinder head casting are all cut off by a saw). This casting method requires a holding furnace (containing molten aluminum), a low-pressure press and a pressurizing mechanism, a pressurizing drive device, etc. (collectively referred to as low-pressure system equipment), a flipping mechanism (to achieve 180-degree flipping), a conveying and moving mechanism, a casting mold (containing relevant sand cores), as well as a clamping mechanism, an upper mold, a left mold, a right mold, a front mold, a rear mold, etc. (collectively referred to as casting system equipment).
Claims
1. A riserless casting mold for aluminum alloy cylinder heads, comprising an upper mold, a left end mold, a right end mold, a front mold, and a rear mold, characterized in that: The lower part of the front mold has an inward front mold protrusion, and the lower part of the rear mold has an inward rear mold protrusion. The inward front mold protrusion and the inward rear mold protrusion are combined to form the lower mold. The upper mold, left end mold, right end mold, front mold and rear mold are combined to form a mold cavity. The bottom of the lower mold has a main runner, an inner runner and a sprue. The sprue is connected to the transition sleeve and the riser pipe in sequence. The upper mold, left end mold, right end mold, front mold and rear mold are respectively installed on the upper template, left template, right template, front template and rear template.
2. The riserless casting mold for aluminum alloy cylinder heads according to claim 1, characterized in that: A water cooling mechanism is installed on the outer side of the upper mold, and a negative pressure suction mechanism is installed on the outer side of the front mold.