A special cast iron cylinder block cooling jacket casting sand mold parting structure

Abstract

A special cast iron cylinder body cooling water jacket casting sand mold parting structure belongs to engine casting technical field. The parting surface of the water jacket casting sand core is provided with a special part, the upper and lower directions of the special part are provided with draft angles, the water jacket casting sand core is provided with a large-diameter water jacket hole position one and a large-diameter water jacket hole position two, the center of the large-diameter water jacket hole position one is located in the special part, and the large-diameter water jacket hole position one and the large-diameter water jacket hole position two are directly cast into shape. The novel sand mold parting structure design ensures the cooling system performance while reducing the processing cost, improving the product quality and eliminating the processing risk, and has remarkable technical advantages and good application prospect.

Description

Technical Field

[0001] This utility model belongs to the field of engine casting technology, specifically a special sand mold parting structure for casting cooling water jackets of cast iron cylinder blocks. Background Technology

[0002] In engine cooling systems, cylinder block water jackets are critical heat dissipation components. Currently, cylinder blocks formed by gravity casting typically have a sand mold parting surface at the center height of the water jacket for demolding. However, when the center point of a large-diameter water jacket hole cannot be adjusted to the original sand mold parting surface due to design limitations, the hole must be formed through machining. Existing technologies have the following drawbacks:

[0003] 1. Machining larger diameter holes requires the use of larger diameter cutting tools, which increases machining costs, extends machining cycle time, and reduces production efficiency;

[0004] 2. During machining, large-diameter cutting tools are prone to interference with the inner wall of the water jacket, affecting machining accuracy and equipment safety;

[0005] 3. Machining holes are prone to sharp edges and burrs, requiring additional processing steps and further increasing costs. Summary of the Invention

[0006] To address the problems existing in the background technology, this utility model provides a special sand mold parting structure for casting cooling water jackets of cast iron cylinder blocks.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a special cast iron cylinder block cooling water jacket casting sand mold parting structure, including a water jacket casting sand core, wherein the water jacket casting sand core includes a parting surface, a special part, a large-diameter water jacket hole position one and a large-diameter water jacket hole position two;

[0008] The parting surface of the water jacket casting sand core is provided with a special part, and the special part is provided with draft angles in both the upper and lower directions. The water jacket casting sand core is provided with a large-diameter water jacket hole one and a large-diameter water jacket hole two. The center of the large-diameter water jacket hole one is located in the special part. The large-diameter water jacket hole one and the large-diameter water jacket hole two are directly cast.

[0009] The upper and lower surfaces of the special part are respectively set with a draft angle of 1°-5° in the upward and downward direction based on the parting surface. This angle setting ensures that the edge of the water jacket hole is not damaged when the sand core is demolded.

[0010] The shape of the special part matches the distribution position of the large-diameter water jacket hole one, so as to ensure that the large-diameter water jacket hole one can be directly formed by sand mold after being centered.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. Reduced processing costs: Through special design, the large-diameter water jacket holes that originally required machining are directly formed during gravity casting, reducing 1-2 machining steps and significantly reducing the processing cost per cylinder block; at the same time, the ≥0.5mm allowance required for machining and the subsequent deburring process are avoided, further saving costs.

[0013] 2. Improve product quality: Special parts are designed with a draft angle of 1°-5° to ensure that the demolding force is ≤50N, which is far lower than the industry standard of 80N, effectively avoiding damage to the hole edges; after casting, the hole edges form a smooth transition with a radius of ≥0.8mm, and the surface roughness of the sand mold Ra≤6.3μm, meeting the sealing requirements of the engine cooling system.

[0014] 3. Eliminate machining risks: For holes with a diameter ≥ 50mm, it solves the vibration and resonance risk caused by the tool length-to-diameter ratio exceeding 3:1 in traditional machining (reducing the resonance probability by 20%), ensuring stable hole dimensional accuracy; at the same time, it avoids interference between the machining tool and the inner wall of the water jacket.

[0015] 4. Ensure stable performance: The change in water jacket width caused by the draft angle is ≤0.5mm. Thermal simulation test shows that the impact on heat dissipation performance is <1%. Under the same working conditions, compared with the traditional machining solution, the maximum difference in water jacket wall temperature is ≤0.5℃ and the difference in heat dissipation efficiency is <0.8%, ensuring that the performance of the cooling system is not affected.

[0016] 5. Expanded application range: Suitable for high-efficiency gasoline engine cast iron cylinder blocks with a vertical distance of >10mm between the center of the water jacket hole and the conventional parting surface, especially with significant advantages in the field of large-diameter water jacket hole machining.

[0017] In summary, this utility model, through its innovative sand mold parting structure design, reduces processing costs, improves product quality, eliminates processing risks, and ensures the performance of the cooling system, demonstrating significant technical advantages and promising application prospects. Attached Figure Description

[0018] Figure 1 This is a front view of the present invention; Detailed Implementation

[0019] The technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of the utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0020] This embodiment describes a special casting sand mold parting structure for a cast iron cylinder block cooling water jacket, including a water jacket casting sand core. The water jacket casting sand core includes a parting surface 1, a special part 2, a large-diameter water jacket hole position one 3, and a large-diameter water jacket hole position two 4.

[0021] The parting surface 1 of the water jacket casting sand core is provided with a special part 2. The special part 2 is provided with draft angles in both the upper and lower directions. The water jacket casting sand core is provided with a large-diameter water jacket hole 1 3 and a large-diameter water jacket hole 2 4. The center of the large-diameter water jacket hole 1 3 is located in the special part 2. The large-diameter water jacket hole 1 3 and the large-diameter water jacket hole 2 4 are directly cast.

[0022] The upper and lower surfaces of the special part 2 are respectively set with a draft angle of 1°-5° in the upward and downward direction based on the parting surface 1. This angle setting ensures that the edge of the water jacket hole is not damaged when the sand core is demolded.

[0023] The shape of the special part 2 matches the distribution position of the large-diameter water jacket hole position 3, so as to ensure that the large-diameter water jacket hole position 3 can be directly formed by sand mold after being centered.

[0024] This invention adds a special part 2 to the parting surface 1 of the water jacket casting sand core, positioning the center of the large-diameter water jacket hole 3, which originally required machining, to the special part 2. The sand core is demolded by using a draft angle of 1°-5° in the vertical direction, so that the hole is directly formed during the gravity casting process, avoiding interference from machining tools, increased costs, and burr problems.

[0025] The structure of special part 2: Special part 2 is a protrusion / groove structure that is perpendicular or inclined to the parting surface 1 (such as a cylindrical protrusion when the large diameter water jacket hole 3 is circular). Its cross-sectional profile is completely matched with the edge of the large diameter water jacket hole 3 to ensure that there is no friction between the sand core and the hole wall during demolding (for example, when the hole diameter is 50mm and the draft angle is 2°, the difference in size between the upper and lower ends of the sand core is ≤1.7mm).

[0026] Hole reservation method: Hole 3 of the large diameter water jacket is reserved through the hollow structure of the special part 2, and hole 4 of the large diameter water jacket is directly opened in the conventional area of ​​the parting surface 1. Both are set with draft angle according to the gravity casting process.

[0027] Mold assembly and casting process: After the sand core is assembled into the mold cavity, the molten iron fills the cavity under the action of gravity. Due to the draft angle design of special part 2, when the molten iron cools and solidifies, a draft angle is formed between the inner wall of the hole and the sand core, avoiding the risk of interference between the tool diameter (e.g., ≥50mm) and the inner wall of the water jacket in traditional machining (machining requires a ≥0.5mm allowance, while casting directly forms without any allowance).

[0028] Demolding and forming effect: When demolding, the water jacket casting sand core is pulled out. The demolding angle of special part 2 makes the separation force between the sand core and the inner wall of the hole ≤50N (industry standard ≤80N). There is no damage to the edge of the hole. After casting, the edge of the hole forms a smooth transition with a radius ≥0.8mm (preferably the surface roughness of the sand mold Ra≤6.3μm). No deburring is required by machining, which meets the sealing requirements of the engine cooling system.

[0029] Draft angle criteria: Within the range of 1°-5°, the change in water jacket width is ≤0.5mm (e.g., for a 50mm wide water jacket, the width increases by 0.43mm at a 5° angle). Thermal simulation tests show that the impact on heat dissipation performance is <1% (e.g., temperature difference ≤0.5℃; compared with the traditional machining hole scheme, under the same working conditions of engine speed 3000r / min and coolant flow rate 20L / min, thermal simulation shows that the maximum temperature difference of the water jacket wall with special parting surface design is ≤0.5℃, and the heat dissipation efficiency difference rate is <0.8%).

[0030] Critical value for hole diameter: When the hole diameter is ≥50mm, the length-to-diameter ratio of traditional machining tools is ≥50mm (e.g., tool length 150mm). According to the "Metal Cutting Processing Handbook", the probability of the tool vibration frequency resonating with the machine tool's natural frequency increases by 20% at this time, while casting direct forming can eliminate this risk.

[0031] In high-efficiency gasoline engine cast iron cylinder blocks, when the vertical distance between the center of the water jacket hole and the conventional parting surface is >10mm, this design can reduce 1-2 machining processes, lower the machining cost per cylinder block, and eliminate the need for machining after the hole is formed, directly meeting the usage requirements.

[0032] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A special cast-iron cylinder block cooling jacket sand mold parting structure characterized by: The water jacket casting sand core includes a parting surface (1), a special part (2), a large-diameter water jacket hole position one (3), and a large-diameter water jacket hole position two (4). The parting surface (1) of the water jacket casting sand core is provided with a special part (2). The special part (2) is provided with a draft angle in both the upper and lower directions. The water jacket casting sand core is provided with a large-diameter water jacket hole one (3) and a large-diameter water jacket hole two (4). The center of the large-diameter water jacket hole one (3) is located in the special part (2). The large-diameter water jacket hole one (3) and the large-diameter water jacket hole two (4) are directly cast.

2. The split pattern of the special cast-iron cylinder block cooling jacket sand mold according to claim 1, characterized in that: The upper and lower surfaces of the special part (2) are respectively based on the parting surface (1) and have a draft angle of 1°-5° in the upward and downward direction. This angle setting ensures that the edge of the water jacket hole is not damaged when the sand core is demolded.

3. The split pattern of the special cast-iron cylinder block cooling jacket sand mold according to claim 1, characterized in that: The shape of the special part (2) matches the distribution position of the large-diameter water jacket hole position one (3) to ensure that the large-diameter water jacket hole position one (3) can be directly formed by sand mold after the center is positioned.

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