Asbestos mat anti-pinch device for complex internal cavity castings

Abstract

The utility model discloses an asbestos pad anti -clamping skin device for complex inner chamber casting, comprising asbestos pad, asbestos pad sets up positioning structure, asbestos pad surface coats and sticks layer, asbestos pad shape and sand core combination place contact surface match, be used for filling gap and isolating metal liquid, positioning structure is boss, the boss is integrally made with asbestos pad. The utility model can accurate anti -clamping skin: with the asbestos pad of shape sand core combination place's inner chamber gap completely sticks, fills the accuracy of 0.05mm, thoroughly blocks the metal liquid infiltration path, and the incidence of clamping skin reduces to 0.1% below.

Description

Technical Field

[0001] This utility model relates to the field of casting technology, specifically to an asbestos pad anti-pinch device for castings with complex internal cavities. Background Technology

[0002] In the casting industry, castings with complex internal cavity structures, such as engine cylinder blocks, hydraulic valve blocks, and pump bodies, often require multiple sets of sand cores to form the internal cavity. During sand core assembly, there are often tiny gaps of 0.1-2mm at the joint surfaces of adjacent sand cores. When pouring high-temperature molten metal, such as molten iron or aluminum, the molten metal can easily seep into these gaps and react thermally with the incompletely solidified sand core surface, forming a difficult-to-clean sintered layer of metal and sand particles.

[0003] Currently, common methods used in the industry to prevent skin inclusion in sand core assemblies include:

[0004] Manual shaping: The contact surfaces are polished before the sand core is assembled to reduce gaps; however, manual operation relies on experience, and tiny gaps are still difficult to completely eliminate, and the efficiency is low.

[0005] Applying a coating layer: Apply refractory coating to the contact surface of the sand core to fill the gaps and isolate the molten metal; however, if the coating layer is uneven in thickness, local weak points may easily form, and molten metal may still seep in.

[0006] Adding binder can improve the bond strength at the sand core assembly; however, excessive binder can increase the brittleness of the sand core, making it prone to disintegration after casting, which in turn exacerbates the risk of skin inclusion.

[0007] The common drawback of the above methods is that they cannot completely fill the complex gaps at the sand core assembly, such as deep holes, narrow grooves, and non-linear joints. The rate of skin inclusion is still as high as 5%-15%. The cleaning is difficult and requires manual hammering, acid etching, or mechanical grinding, which seriously affects the casting production efficiency and surface quality.

[0008] Therefore, there is an urgent need for an anti-skin-clamping device that can precisely fit the shape of the inner cavity of the sand core assembly, fill the tiny gaps, and isolate the molten metal, so as to solve the skin-clamping problem of castings with complex inner cavities. Utility Model Content

[0009] In order to overcome the shortcomings of the prior art and solve at least one of the technical problems mentioned in the background art, this utility model provides an asbestos pad anti-pinch device for castings with complex internal cavities.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] An asbestos pad anti-skin-clamping device for castings with complex internal cavities includes an asbestos pad with a positioning structure and an adhesive layer coated on its surface. The shape of the asbestos pad matches the contact surface at the sand core assembly to fill gaps and isolate molten metal. The positioning structure is a boss, which is integrally formed with the asbestos pad.

[0012] Furthermore, the surface of the asbestos pad is provided with micro-textures.

[0013] Furthermore, the boss is a prismatic boss.

[0014] Furthermore, it also includes a first combined sand core and a second combined sand core, wherein a first positioning groove is provided on the first combined surface of the first combined sand core, and a second positioning groove is provided on the second combined surface of the second combined sand core;

[0015] Specifically, the boss includes a lower boss disposed on the lower end face of the asbestos pad and an upper boss disposed on the upper end face of the asbestos pad. The lower boss is interference-fitted with the first positioning groove, and the upper boss is interference-fitted with the second positioning groove.

[0016] Furthermore, the depth of the first positioning groove is greater than the height of the lower boss, and the depth of the second positioning groove is greater than the height of the upper boss.

[0017] Furthermore, the lower outer periphery of the lower boss and the upper outer periphery of the upper boss are chamfered to facilitate compression of the positioning groove surface during the interference fit process.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. Precise anti-skin-fraying: The conformal asbestos pad fits perfectly into the inner cavity gap of the sand core assembly (filling accuracy ±0.05mm), completely blocking the path of molten metal penetration, reducing the skin-fraying rate to below 0.1% (compared to 5%-15% in traditional processes).

[0020] 2. Strong adaptability: Asbestos pads (molded) can be customized according to the shape of the sand core cavity, which is suitable for complex structures such as deep holes, narrow grooves, and non-linear joints, and has strong versatility.

[0021] 3. Highly efficient cleaning: No skin or only trace residue (which can be blown away with compressed air), no need for manual knocking or acid etching, improving cleaning efficiency by more than 80%.

[0022] 4. Improve casting quality: Avoid casting dimensional deviations and surface roughness caused by inclusions, increasing the casting pass rate by 10%-15%. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an asbestos pad anti-pinch device for castings with complex internal cavities according to this utility model.

[0024] Figure 2 This is a top view schematic diagram of the first combined sand core in this utility model.

[0025] Figure 3 This is a bottom view of the second positioning groove in this utility model.

[0026] Figure 4 This is a schematic diagram of the assembly structure of the asbestos pad and the combined sand core in this utility model.

[0027] In the figure: 1-Asbestos pad; 2-Location hole; 21-Boss; 211-Lower boss; 212-Upper boss; 3-Adhesive; 4-First combination sand core; 41-First positioning groove; 5-Second combination sand core; 51-Second positioning groove. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Example 1:

[0030] Please see Figures 1 to 4 The present invention provides an asbestos pad anti-pinch device for castings with complex internal cavities, including a conformal refractory asbestos pad 1, wherein the asbestos pad 1 is provided with a positioning structure 2, and the surface of the asbestos pad 1 is coated with an adhesive layer 3.

[0031] The shape of the asbestos pad 1 perfectly matches the contact surface at the sand core assembly, and is used to fill the gap and isolate the molten metal.

[0032] The positioning structure 2 is used to fix the asbestos pad at the target position of the sand core assembly.

[0033] The adhesive layer 3 is applied to the contact surface between the asbestos pad 1 and the sand core to enhance the bonding force between the asbestos pad 1 and the sand core.

[0034] Specifically, the asbestos pad 1 is made of aluminum silicate fiber Al2O3·SiO2 as the main material, with 5%-10% alumina micro powder Al2O3 and 3%-5% silica sol binder added, and is made by molding and high-temperature sintering at 1000℃-1200℃.

[0035] Specifically, the asbestos pad 1 has the following structural design: the thickness of the asbestos pad 1 is δ=1-3mm, which is adjusted according to the gap size of the sand core assembly. When the gap is 0.1-1mm, δ=1mm; when the gap is 1-2mm, δ=2mm; and when the gap is >2mm, δ=3mm. The surface of the asbestos pad 1 is provided with micro-protrusions with a height of 0.1-0.3mm and a spacing of 1-2mm to enhance the mechanical interlocking with the surface of the sand core. The asbestos pad 1 has a temperature resistance range of ≥1600℃, which meets the high temperature requirements of most casting processes, and a thermal conductivity of ≤0.1W / (m·K), providing excellent thermal insulation performance.

[0036] Furthermore, the positioning structure 2 is a boss 21, which is integrally formed with the asbestos pad 1 by a molding and sintering process.

[0037] Specifically, the boss 21 is a prismatic boss, and the boss and the groove at the sand core assembly are interference fit with an interference amount of 0.05-0.1mm to prevent the asbestos pad from shifting during casting.

[0038] Furthermore, the adhesive layer 3 uses a low-temperature fast-drying silicate adhesive such as sodium silicate solution with a modulus of 2.5-3.0, or a high-temperature phenolic resin adhesive with a curing temperature of 80℃-120℃; the coating process is as follows: a 0.05-0.1mm thick adhesive layer 3 is uniformly coated on the contact surface between the asbestos pad 1 and the sand core, and after being left to dry for 5-10 minutes, it is bonded to the sand core and fixed by curing with the adhesive.

[0039] Example 2:

[0040] Based on Embodiment 1, this embodiment also includes a first combined sand core 4 and a second combined sand core 5. The first combined sand core 4 has a first positioning groove 41 on its first combined surface, and the second combined sand core 5 has a second positioning groove 51 on its second combined surface. The boss 21 includes a lower boss 211 on the lower end face of the asbestos pad 1 and an upper boss 212 on the upper end face of the asbestos pad 1. The lower boss 211 is interference-fitted with the first positioning groove 41, and the upper boss 212 is interference-fitted with the second positioning groove 51.

[0041] Specifically, the depth of the first positioning groove 41 is greater than the height of the lower boss 211, and the depth of the second positioning groove 51 is greater than the height of the upper boss 212, so that the sand particles squeezed out during the interference fit have a space to be accommodated. The positioning groove and the boss are tightly fitted by the elastic force of the sand core after the interference fit, and the positioning asbestos pad 1 is positioned.

[0042] Specifically, the lower outer periphery of the lower boss 211 and the upper outer periphery of the upper boss 212 are chamfered to facilitate compression of the positioning groove surface during the interference fit process.

[0043] When the asbestos pad 1 has a long and a short axis, a set of lower bosses 211 and upper bosses 212 are provided on the long axis, and a set of lower bosses 211 and upper bosses 212 are provided on the short axis.

[0044] Working principle of an asbestos pad anti-pinch device for castings with complex internal cavities:

[0045] Pre-treatment stage: Based on the inner cavity shape of the sand core assembly, the shape is obtained through 3D scanning or mold mapping, and a custom-made conformal refractory asbestos pad 1 is processed to ensure that its shape and gap are perfectly matched.

[0046] Assembly stage: Apply adhesive layer 3 to the surface of asbestos pad 1; fix asbestos pad 1 to the first combined sand core 4 through the lower boss 211 of positioning structure 2 to prevent displacement;

[0047] Sand core assembly stage: The second sand core 5 is combined with the first sand core 4 with asbestos pad 1 according to the process requirements. The second positioning groove 51 is interference-fitted with the upper boss 212, and the asbestos pad 1 fills the tiny gaps.

[0048] During the casting stage: When the high-temperature molten metal is injected into the sand mold, the asbestos pad 1 effectively isolates the molten metal from the surface of the sand core due to its high temperature resistance and good heat insulation. At the same time, its micro-textured structure and the bonding layer 3 work together to prevent the molten metal from seeping into the gaps, thus fundamentally eliminating the formation of skin.

[0049] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0050] In this utility model, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0051] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0052] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0053] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An asbestos pad anti-pinch device for castings with complex internal cavities, comprising an asbestos pad, characterized in that, The asbestos pad is provided with a positioning structure, and the surface of the asbestos pad is coated with an adhesive layer; the shape of the asbestos pad matches the contact surface at the sand core assembly, and is used to fill the gap and isolate the molten metal; the positioning structure is a boss, and the boss is integrally formed with the asbestos pad.

2. The asbestos pad anti-pinch device for castings with complex internal cavities according to claim 1, characterized in that, The surface of the asbestos pad has micro-textures.

3. The asbestos pad anti-pinch device for castings with complex internal cavities according to claim 1, characterized in that, The boss is a prismatic boss.

4. The asbestos pad anti-pinch device for castings with complex internal cavities according to claim 1, characterized in that, It also includes a first combined sand core and a second combined sand core, wherein a first positioning groove is provided on the first combined surface of the first combined sand core and a second positioning groove is provided on the second combined surface of the second combined sand core. The boss includes a lower boss disposed on the lower end face of the asbestos pad and an upper boss disposed on the upper end face of the asbestos pad. The lower boss is interference-fitted with the first positioning groove, and the upper boss is interference-fitted with the second positioning groove.

5. The asbestos pad anti-pinch device for castings with complex internal cavities according to claim 4, characterized in that, The depth of the first positioning groove is greater than the height of the lower boss, and the depth of the second positioning groove is greater than the height of the upper boss.

6. The asbestos pad anti-pinch device for castings with complex internal cavities according to claim 4, characterized in that, The lower outer periphery of the lower boss and the upper outer periphery of the upper boss are chamfered to facilitate compression of the positioning groove surface during the interference fit process.

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