Method for eliminating spring seat face shrinkage of diesel engine cylinder head

Abstract

This invention provides a molding method for eliminating shrinkage porosity on the cylinder head spring seat surface of a diesel engine, belonging to the field of casting technology. Specifically, it includes the following steps: fabricating a #1 conical chill and a #2 cylindrical chill, with the surface of the #1 conical chill coated with a layer of paint; assembling the chills: during the core fabrication of the diesel engine cylinder head, the #1 conical chill is placed at the forming position of the cylinder head spring seat surface, tightly fitting around the formed cylinder head spring seat surface; the #2 cylindrical chill is arranged below the #1 conical chill, with a 1mm gap between the upper end of the #2 cylindrical chill and the bottom surface of the #1 conical chill; after the diesel engine cylinder head is cast, cleaning only requires removing the #1 conical chill, avoiding the formation of iron-clad sand. This invention, by changing the structure and arrangement of the chills in the cylinder head spring seat, eliminates shrinkage porosity on the cast cylinder head spring seat surface, while also facilitating cleaning and production use.

Description

Technical Field

[0001] This invention belongs to the field of casting technology, specifically relating to a molding method for eliminating shrinkage and porosity of the cylinder head spring seat surface in diesel engines. Background Technology

[0002] Diesel engines operate by generating powerful thrust through the combustion of diesel fuel, which drives the piston in a reciprocating motion to output power. This continuous reciprocating motion causes the surface temperature of the cylinder head, connected to the piston, to rise, reaching up to 2000℃. This poses a severe test to the overall performance of the cylinder head, thus requiring stringent standards from the raw material stage of cylinder head production. To withstand the high temperature and high pressure environment, the cylinder head incorporates flow channels, bores, and cooling water passages. It also houses intake and exhaust valves, fuel injectors, indicator valves, starter valves, and safety valves. These factors make the cylinder head one of the most structurally complex parts in a diesel engine, significantly increasing the difficulty of its casting.

[0003] After generations of research, we are now able to manufacture most types of cylinder head parts. However, there are still some problems in the production of high-power diesel engine cylinder heads, the most frequent of which is the loosening of the cylinder head spring seat surface.

[0004] Currently, the chills designed to address shrinkage issues in cylinder head spring seat surfaces are two-part cylindrical structures. While these chills can eliminate shrinkage, their use increases the difficulty of cleaning the cylinder head and raises production costs. This is because these chills need to be placed within a sand core and used together with it on the cylinder head spring seat surface. This method works for relatively small diesel engine cylinder heads, but when used in large diesel engine cylinder heads (cylinder head blank weight ≥ 500 kg), the larger size requires more molten iron, resulting in a longer holding time for the casting. While a sufficient sand core can usually withstand the high temperatures, the need to place the chill on the spring seat surface significantly reduces the sand content, leaving only a thin layer of sand on the chill surface. This greatly weakens the sand core's high-temperature resistance, leading to a problem of sand encasing iron. In severe cases, the sand may melt, bonding the casting to the chill, increasing cleaning difficulty. Careless cleaning can damage the casting during chill removal, potentially rendering the cylinder head unusable. This invention is a further improvement on the existing process for removing cylinder head spring shrinkage, in order to achieve a solution suitable for actual production use. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a molding method for eliminating shrinkage porosity on the cylinder head spring seat surface of a diesel engine. The purpose of this invention is to change the structure and arrangement of the chills used to form the cylinder head spring seat so that the cast cylinder head spring seat surface is free from shrinkage porosity, and is easy to clean and use in production.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A forming method to eliminate shrinkage on the spring seat surface of a diesel engine cylinder head. This method avoids the occurrence of shrinkage on the spring seat surface and the difficulty in cleaning during the manufacturing process of the diesel engine cylinder head by changing the structure and installation method of the chill. Specifically, it includes the following steps:

[0008] Step 1): Fabricate a #1 conical chill and a #2 cylindrical chill, wherein the surface of the #1 conical chill is coated with a layer of paint.

[0009] Step 2): Assemble the chills: When making the lower core of the diesel engine cylinder head, place the #1 conical chill on the forming position of the cylinder head spring seat surface and fit it tightly around the cylinder head spring seat surface. The #2 cylindrical chill is arranged below the #1 conical chill, and the upper end of the #2 cylindrical chill maintains a 1mm gap with the bottom surface of the #1 conical chill.

[0010] Step 3): After the diesel engine cylinder head is cast, during cleaning, simply remove the #1 conical chill directly to avoid the formation of iron-clad sand.

[0011] In the above steps, the structure of the #1 conical chill includes a lower conical chill section and an upper cylindrical section; the surface of the lower conical chill section is a conical surface, and the large-diameter end of the lower conical chill section is connected to the upper cylindrical section and the two are coaxial.

[0012] The diameter of the large-diameter end of the lower conical chill section is greater than the diameter of the inner cylindrical surface of the cylinder head spring seat. The diameter of the small-diameter end of the lower conical chill section is 0.5 mm smaller than the diameter of the inner cylindrical surface of the cylinder head spring seat. The height of the lower conical chill section is 10 mm higher than the depth of the cylinder head spring seat, and the maximum radius of the protruding part is 5 mm larger than the radius of the cylinder head spring seat. The diameter of the upper cylindrical section is greater than the diameter of the large-diameter end of the lower conical chill section.

[0013] The surface of the lower conical chill section is coated with a coating layer, which is a zircon powder coating.

[0014] The No. 2 cylindrical chill adopts a general-purpose cylindrical chill structure.

[0015] Advantages of this invention compared to existing technologies:

[0016] 1. This solution modifies the structure of the chill, creating a conical chill structure that acts like a bottle stopper. Through a well-designed size, the chill fits snugly against the cylinder head spring seat surface. Only a thin coating is applied around the chill before installation on the spring seat surface, preventing sand particles from falling in and causing inclusion defects. Cleaning with this chill is simple; just remove it, avoiding the formation of sand-covered iron. The operation is simple and easy to clean. This method not only prevents shrinkage and loosening of the cylinder head spring seat surface but also facilitates operation in actual production without creating new problems.

[0017] 2. In order to make the chill fit snugly against the spring seat surface of the cylinder head blank, the lower radius of the #1 conical chill is 0.5mm smaller than the radius of the spring seat surface. The surface is coated with a paint layer, and the height is 10mm higher than the depth of the spring seat surface. The radius of the 10mm higher part is 5mm larger than the radius of the spring seat surface. This design can make the chill fit tightly with the upper sand core, while facilitating installation and preventing the chill from separating from the sand core.

[0018] 3. The structure of the #1 conical chill in this design has a certain slope. This design facilitates demolding. When lowering the core, the tops of the #1 conical chill and the #2 cylindrical chill are placed close together. This installation method prevents slag from entering the lower part of the spring seat surface and causing new defects.

[0019] 4. This solution uses a new type of chilled iron, which can effectively solve the problem of cylinder head spring seat surface shrinkage and loosening, and is also easy to clean, providing a brand-new solution to the problem of cylinder head spring seat surface shrinkage and loosening. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the #1 conical chill in this invention;

[0022] Figure 3 This is a rendering of a cylinder head manufactured using the method of the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0025] Please see Figure 1-3 The embodiments of the present invention are described in detail below.

[0026] Example: A forming method to eliminate shrinkage on the spring seat surface of a diesel engine cylinder head. This method avoids shrinkage on the spring seat surface during the manufacturing process of the diesel engine cylinder head by changing the structure and installation method of the chill; see also Figure 1 As shown, the specific steps include:

[0027] Step 1): Fabricate a dedicated #1 conical chill 3 and a general-purpose #2 cylindrical chill 4. The surface of the #1 conical chill 3 is coated with a layer of paint.

[0028] Step 2): Assemble the chills: When making the lower core of the diesel engine cylinder head 1, place the #1 conical chill 3 at the forming position of the cylinder head spring seat 2, so that it fits tightly with the cylinder head spring seat 2 after forming. The #2 cylindrical chill 4 is coaxially arranged at the lower part of the #1 conical chill 3, and the upper end face of the #2 cylindrical chill 4 maintains a 1mm gap with the bottom face of the #1 conical chill 3.

[0029] Step 3): After the diesel engine cylinder head 1 is cast, during cleaning, simply remove the #1 conical chill 3 directly to avoid iron-clad sand.

[0030] The structure of the #1 conical chill 3 in the above steps is as follows: See Figure 2 As shown, it includes a lower conical chill section 3-1 and an upper cylindrical section 3-2; the surface of the lower conical chill section 3-1 is a conical surface, and the large-diameter end of the lower conical chill section 3-1 is connected to the upper cylindrical section 3-2 and the two are coaxial.

[0031] When designing the dimensions of the #1 conical chill 3, in order to ensure that the #1 conical chill 3 fits snugly against the cylinder head blank spring seat surface, please refer to... Figure 2As shown, the large-diameter end of the lower conical chill section 3-1 is larger than the inner cylindrical surface diameter of the cylinder head spring seat surface 2, the small-diameter end of the lower conical chill section 3-1 is 0.5mm smaller than the inner cylindrical surface diameter of the cylinder head spring seat surface 2, and the height of the lower conical chill section 3-1 is 10mm higher than the depth of the cylinder head spring seat surface 2, with the maximum radius of the protruding portion being 5mm larger than the radius of the cylinder head spring seat surface 2; the diameter of the upper cylindrical section 3-2 is larger than the large-diameter end diameter of the lower conical chill section 3-1. This design allows the #1 conical chill 3 to be tightly bonded to the upper sand core, while also facilitating installation and preventing the chill from detaching from the sand core.

[0032] According to the use of the #1 conical chill 3, a coating layer is coated on the surface of the lower conical chill section 3-1. Preferably, the coating layer is a zircon powder coating, which can effectively prevent the casting from sticking to the chill and causing cleaning difficulties.

[0033] In this embodiment, the structure of the #1 conical chill 3 has a certain slope. This design is to facilitate demolding. When lowering the core, the bottom of the #1 conical chill 3 is placed close to the top of the #2 cylindrical chill 4. This installation method prevents slag from entering the lower part of the spring seat surface and causing new defects.

[0034] Product efficacy, such as Figure 3 The image shows a cylinder head produced using this method. After cutting and inspecting the cylinder head spring seat surface, it was found that there was no shrinkage or loosening, meeting production requirements, and cleaning was convenient. Therefore, it is concluded that the chill structure and arrangement of this solution can effectively solve the problem of shrinkage and loosening of the cylinder head spring seat surface, while also facilitating cleaning. This provides a completely new solution to the problem of shrinkage and loosening of the cylinder head spring seat surface, and the operation is simple and convenient.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0036] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A molding method for eliminating shrinkage of the cylinder head spring seat surface in diesel engines, characterized in that: This method avoids shrinkage on the spring seat surface during diesel engine cylinder head manufacturing and facilitates cleaning by changing the structure and installation method of the chill; specifically, it includes the following steps: Step 1): Fabricate a #1 conical chill (3) and a #2 cylindrical chill (4), wherein the surface of the #1 conical chill (3) is coated with a layer of paint. Step 2): Assemble the chills: When casting the cylinder head (1) of the diesel engine, place the #1 conical chill (3) at the forming position of the cylinder head spring seat (2) and fit it tightly around the cylinder head spring seat (2). The #2 cylindrical chill (4) is arranged at the lower part of the #1 conical chill (3). The upper end of the #2 cylindrical chill (4) maintains a 1mm gap with the bottom surface of the #1 conical chill (3). Step 3): After the diesel engine cylinder head (1) is cast, during cleaning, simply remove the #1 cone-shaped chill (3) to avoid the occurrence of iron-clad sand.

2. The molding method for eliminating shrinkage of the cylinder head spring seat surface of a diesel engine according to claim 1, characterized in that: In the above steps, the structure of the #1 conical chill (3) includes a lower conical chill section (3-1) and an upper cylindrical section (3-2); the surface of the lower conical chill section (3-1) is a conical surface, and the large diameter end of the lower conical chill section (3-1) is connected to the upper cylindrical section (3-2) and the two are coaxial.

3. The molding method for eliminating shrinkage of the cylinder head spring seat surface in a diesel engine according to claim 2, characterized in that: The diameter of the large-diameter end of the lower conical chill section (3-1) is greater than the diameter of the inner cylindrical surface of the cylinder head spring seat (2). The diameter of the small-diameter end of the lower conical chill section (3-1) is 0.5 mm smaller than the diameter of the inner cylindrical surface of the cylinder head spring seat (2). The height of the lower conical chill section (3-1) is 10 mm higher than the depth of the cylinder head spring seat (2), and the maximum radius of the protruding part is 5 mm larger than the radius of the cylinder head spring seat (2). The diameter of the upper cylindrical section (3-2) is greater than the diameter of the large-diameter end of the lower conical chill section (3-1).

4. The molding method for eliminating shrinkage of the cylinder head spring seat surface in a diesel engine according to claim 3, characterized in that: The surface of the lower conical chill section (3-1) is coated with a coating layer, which is a zircon powder coating.

5. The molding method for eliminating shrinkage of the cylinder head spring seat surface of a diesel engine according to claim 1, characterized in that: The No. 2 cylindrical chill (4) adopts a general-purpose cylindrical chill structure.

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