Sand core manufacturing method, sand core manufacturing device, and sand core

Abstract

A sand core manufacturing method. A sand core comprises a first core body (1) and a second core body (2) that can be assembled. The second core body is heated, so that a mating block (11) formed on the first core body is inserted into an accommodating portion (21) on the second core body, thereby assembling a sand core. Also disclosed are a sand core manufacturing device and a sand core. By means of the characteristics of dimensional change in the second core body caused by temperature variation of the second core body itself, the assembly of the first core body and the second core body is realized. Compared with conventional core assembly methods, the processes of bonding and flash trimming are eliminated, thereby significantly shortening the production cycle and reducing production costs. The sand core manufactured on the basis of the sand core manufacturing method has low gas evolution due to the absence of an adhesive, thereby improving the quality of castings.

Description

Sand core preparation method, sand core preparation device and sand core

[0001] This application claims priority to the Chinese patent application No. 2024112901943 filed on September 14, 2024 with the China National Intellectual Property Office, the content of which is incorporated herein in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of sand core production, for example, to a sand core preparation method, a sand core preparation device and a sand core. BACKGROUND

[0003] In the production of castings, due to the complexity of the structure of the castings, the strict standards of the size accuracy and the high requirements of the surface quality, it is usually necessary to produce with the help of complex sand cores. The sand core is divided into solid and hollow two kinds, but whether it is a solid sand core or a hollow sand core, when the core is assembled, the adjacent core bodies are bonded and formed by using an adhesive, and after the bonding is completed, the fitting gap between the adjacent core bodies needs to be repaired with a repair paste, thereby prolonging the production cycle and increasing the production cost. SUMMARY

[0004] The present application provides a sand core preparation method, a sand core preparation device and a sand core to solve the problem that in the related art, whether it is a solid sand core or a hollow sand core, when the core is assembled, the adjacent core bodies are bonded and formed by using an adhesive, and after the bonding is completed, the fitting gap between the adjacent core bodies needs to be repaired with a repair paste, thereby prolonging the production cycle and increasing the production cost.

[0005] The present application provides a sand core preparation method, a sand core preparation device and a sand core to solve the problem that in the related art, whether it is a solid sand core or a hollow sand core, when the core is assembled, the adjacent core bodies are bonded and formed by using an adhesive, and after the bonding is completed, the fitting gap between the adjacent core bodies needs to be repaired with a repair paste, thereby prolonging the production cycle and increasing the production cost.

[0006] The first core body is prepared so that the first core body forms a fitting block;

[0007] The second core body is prepared so that the second core body forms a receiving portion capable of accommodating the fitting block and interference-fitting with the fitting block;

[0008] The second core body is heated to enable the fitting block to be inserted into the receiving portion;

[0009] The fitting block on the first core body is inserted into the receiving portion on the second core body to form a sand core;

[0010] The sand core is cooled to enable the receiving portion to tightly hold the fitting block.

[0011] In an embodiment, the first core body and the second core body are both prepared by using inorganic resin sand.

[0012] In one embodiment, the second core is prepared after the first core has cooled.

[0013] In one embodiment, the sand core is hollow.

[0014] In one embodiment, the contour of the receiving portion is similar to the outer contour of the second core.

[0015] In one embodiment, a stepped surface is provided on the side wall of the receiving portion, and a protrusion that fits against the stepped surface is provided on the mating block.

[0016] In one embodiment, a limiting groove is provided on the step surface, and a limiting block is provided on the mating block, wherein the limiting block can be embedded and engaged in the limiting groove.

[0017] In one embodiment, a compensation hole communicating with the limiting groove is provided on the stepped surface.

[0018] This application embodiment also provides a sand core preparation apparatus, which prepares sand cores using the sand core preparation method described above. The sand core preparation apparatus includes:

[0019] A first mold includes a first cavity and a first forming part disposed in the first cavity corresponding to the mating block. The first mold is configured to prepare the sand material in the first cavity into the first core.

[0020] The second mold includes a second cavity and a second forming part disposed in the second cavity corresponding to the receiving portion. The second mold is configured to prepare the sand material in the second cavity into the second core and is configured to heat the prepared second core.

[0021] This application also provides a sand core, prepared according to the sand core preparation method described above. Attached Figure Description

[0022] Figure 1 is a structural schematic diagram of the second core provided in this application;

[0023] Figure 2 is a structural schematic diagram of the first core provided in this application;

[0024] Figure 3 is a schematic diagram of the structure of the sand core provided in this application;

[0025] Figure 4 is a flowchart of the sand core preparation method provided in this application.

[0026] In the figure: 1. First core; 11. Mating block; 111. Protrusion; 112. Limiting block; 2. Second core; 21. Receiving part; 211. Step surface; 212. Limiting groove; 213. Compensation hole. DETAILED DESCRIPTION

[0027] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the above-described accompanying drawings.

[0028] In this application, the terms "including", "containing", "having" or any other similar words are intended to cover a non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or apparatus including the element.

[0029] In this application, the term "and / or" is a description of the association relationship between the associated objects, which means that there can be three kinds of relationships. For example, a centrifugal vortex magnetic force pump and / or a centrifugal vortex magnetic force pump can mean that there is only one centrifugal vortex magnetic force pump, there is a centrifugal vortex magnetic force pump and a centrifugal vortex magnetic force pump, and there is only a centrifugal vortex magnetic force pump. In addition, the character " / " in this application generally represents that the front and rear associated objects are a "and / or" relationship.

[0030] In this application, the terms "connection", "combination", "coupling", "mounting" can be direct connection, combination, coupling or mounting, or indirect connection, combination, coupling or mounting. Among them, for example, direct connection refers to the connection of two parts or components without the need for an intermediate part, and indirect connection refers to the connection of two parts or components with at least one intermediate part. The two parts or components are connected through the intermediate part. In addition, "connection" and "coupling" are not limited to physical or mechanical connection or coupling, and can include electrical connection or coupling.

[0031] In this application, those of ordinary skill in the art will understand that the relative terms used in connection with a quantity or a condition (for example, "about", "approximately", "substantially", etc.) include the numerical value and have the meaning indicated by the context. For example, the relative terms at least include the degree of error related to the measurement of a specific value, the tolerance caused by manufacturing, assembly, use, etc. related to a specific value. Such terms should also be considered to disclose the range defined by the absolute values of the two endpoints. The relative terms can refer to the addition or subtraction of a certain percentage (for example, 1%, 5%, 10% or more) of the indicated value. The numerical value without the relative term should also be disclosed as a specific value with a tolerance. In addition, "substantially" when expressing the relative angular positional relationship (for example, substantially parallel, substantially perpendicular), can refer to the addition or subtraction of a certain degree (for example, 1 degree, 5 degrees, 10 degrees or more) based on the indicated angle.

[0032] In this application, those of ordinary skill in the art will understand that the functions performed by the components can be performed by one component, multiple components, one part, or multiple parts. Similarly, the functions performed by the parts can also be performed by one part, one component, or a combination of multiple parts.

[0033] In this application, the terms "upper", "lower", "left", "right", "front", "back" and the like are described in the orientation and positional relationship shown in the drawings, and should not be understood as limiting the embodiments of the present application. In addition, it is also understood in the context that when referring to one element connected to another element "on" or "under", it can not only be directly connected to another element "on" or "under", but also indirectly connected to another element "on" or "under" through an intermediate element. It should also be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like not only represent the positive direction, but also can be understood as the side direction. For example, the lower side can include the directly below, the left below, the right below, the front below and the back below, etc.

[0034] Referring to FIGS. 1-4, the present embodiment provides a sand core preparation method for preparing a sand core, the sand core including a first core body 1 and a second core body 2 capable of being assembled, the sand core preparation method including:

[0035] Preparation of the first core body 1 to form a fitting block 11 on the first core body 1;

[0036] Preparation of the second core body 2 to form a receiving portion 21 capable of accommodating the fitting block 11 and in interference fit with the fitting block 11 on the second core body 2;

[0037] Heating treatment of the second core body 2 to enable the fitting block 11 to be inserted into the receiving portion 21;

[0038] Assembly of the sand core by inserting the fitting block 11 on the first core body 1 into the receiving portion 21 on the second core body 2.

[0039] The sand core is cooled to make the accommodating portion 21 tightly fit the fitting block 11.

[0040] Based on the above, the embodiment realizes the assembly of the first core 1 and the second core 2 by the size change of the second core 2 caused by the temperature change of the second core 2 itself, cancels the bonding and the trimming process compared with the traditional core assembly method, and thus significantly shortens the production cycle and reduces the production cost.

[0041] The bonding process is a process of bonding adjacent cores in the traditional core assembly method, and the trimming process is a process of repairing the fitting gap between adjacent cores in the traditional core assembly method. In addition, the trimming process also increases the probability of abnormal sand core, and if the repair is not good, it will cause defects in the inner cavity of the casting, and even cause the product to be scrapped. The embodiment can avoid this problem.

[0042] The fitting gap between the fitting block 11 and the accommodating portion 21 is selected according to the actual application scene, wherein the main reference characteristic is the shrinkage rate of the second core 2, that is, the expansion rate of the second core 2 in the high-temperature state, so as to insert the fitting block 11 on the first core 1 into the accommodating portion 21 on the second core 2.

[0043] It is worth noting that in the pouring of materials such as steel and aluminum which are very sensitive to gas, the gas emission amount of the sand core will greatly affect the quality of the casting. The gas emitted by the sand core is easy to cause defects such as pores and pinholes in the casting. However, the traditional sand core assembly is connected and formed by using adhesive, and the gas emission amount of the adhesive is much larger than that of the sand material used to prepare the sand core. Based on the above, the embodiment realizes the assembly of the first core 1 and the second core 2 by the size change of the second core 2 caused by the temperature change of the second core 2 itself, cancels the bonding process compared with the traditional core assembly method, that is, the adhesive is not needed in the embodiment, and thus the influence of the large gas emission amount of the adhesive on the casting can be avoided, and the quality of the casting is improved.

[0044] Generally, most of the sand materials (sand core materials) used to prepare sand cores are coated sand and cold core resin sand. In the process of manufacturing sand cores by using coated sand and cold core resin sand, resin sand is added with resin and curing agent or catalyst. When manufacturing, the resin will emit a lot of pollutants, such as methyl furan, benzene, dimethyl furan, toluene, p-xylene, o-xylene, phenol, methyl phenol, naphthalene, etc. In addition, catalysts such as triethylamine will also emit pollutants. The preparation of inorganic resin sand core can effectively reduce the emission of pollutants. Therefore, in the embodiment, the first core 1 and the second core 2 are both prepared by using inorganic resin sand. It should be noted that the method of preparing the inorganic resin sand core is related technology, and thus is not described herein.

[0045] To further improve the production efficiency of the sand core, in this embodiment, the preparation of the second core 2 is started after the first core 1 is cooled. It can be understood that the inorganic resin sand requires a high-temperature environment for core preparation, so the production environment of the second core 2 can be used for high-temperature treatment. Correspondingly, after the first core 1 is cooled, the preparation of the second core 2 is started, which can directly assemble the second core 2 just prepared in a high-temperature state with the first core 1 in a normal temperature state. In this way, on the one hand, the production cycle can be further shortened, and the production efficiency can be improved. On the other hand, the production cost can be further reduced. It should be pointed out that in this embodiment, the design temperature when the second core 2 is assembled with the first core 1 is 200°, and the temperature just after preparation is about 200°. Of course, in other embodiments, the design temperature can also be selected as 190°, 180°, 170°, etc. This embodiment does not require and limit this.

[0046] It can be understood that the use amount of the sand core material of the solid sand core is large, and the production cost is high. Therefore, to solve this problem, in this embodiment, the sand core is hollow, that is, the sand core prepared in this embodiment is a hollow sand core. In this way, the use amount of the sand core material can be significantly reduced, and the production cost can be reduced. The preparation method of the hollow sand core is a related technology, and therefore will not be described in detail.

[0047] The contour of the accommodating portion 21 is similar to the outer contour of the second core 2. In this way, the accommodating portion 21 can uniformly enlarge along the regularity of the high-temperature expansion of the second core 2, so that the fitting block 11 can be smoothly inserted into the accommodating portion 21.

[0048] To make the accommodating portion 21 and the fitting block 11 more firmly clamped, a stepped surface 211 is arranged on the side wall of the accommodating portion 21, and a protrusion 111 corresponding to the stepped surface 211 is arranged on the fitting block 11. A limiting groove 212 is arranged on the stepped surface 211, and a limiting block 112 is arranged on the fitting block 11, which can be embedded and clamped in the limiting groove 212. In this way, when the limiting block 112 is embedded in the limiting groove 212, the fitting block 11 can be guided, and the fitting block 11 can be more accurately inserted into the accommodating portion 21.

[0049] The stepped surface 211 is provided with a compensation hole 213 communicating with the limiting groove 212. In this way, the problem that the slot wall of the limiting groove 212 is cracked during cooling shrinkage can be avoided, and the fitting gap between the accommodating portion 21 and the fitting block 11 can be affected, so that the core assembly quality can be improved. The compensation hole 213 is provided with a plurality of compensation holes, which are distributed on the circumferential side of the stepped surface 211. It can be understood that through the plurality of compensation holes 213 distributed on the circumferential side of the stepped surface 211, the problem of cracking of the accommodating portion 21 can be further avoided.

[0050] The embodiment further provides a sand core preparation device for preparing the sand core by the sand core preparation method. The sand core preparation device comprises a first mold and a second mold. The first mold comprises a first cavity and a first forming part corresponding to the matching block 11 in the first cavity. The first mold is configured to prepare the sand material in the first cavity into the first core body 1. The second mold comprises a second cavity and a second forming part corresponding to the accommodating part 21 in the second cavity. The second mold is configured to prepare the sand material in the second cavity into the second core body 2 and is configured to heat the prepared second core body 2.

[0051] It can be understood that the first core body 1 and the second core body are prepared by the first mold and the second mold respectively, and the second core body 2 is heated by the second mold, so that the assembly of the first core body 1 and the second core body 2 can be realized. Compared with the traditional core assembly method, the processes of bonding and trimming are cancelled, thereby significantly shortening the production cycle and reducing the production cost.

[0052] The embodiment further provides a sand core prepared according to the sand core preparation method. It can be understood that the sand core prepared according to the sand core preparation method has low gas emission because no adhesive is used, which helps to improve the quality of the casting.

Claims

1. A sand core preparation method for preparing a sand core, the sand core comprising a first core body (1) and a second core body (2) capable of being assembled, the method comprising: preparing the first core body (1) to form a fitting block (11) on the first core body (1) ; preparing the second core body (2) to form a receiving portion (21) capable of accommodating the fitting block (11) and in interference fit with the fitting block (11) on the second core body (2) ; performing a heating treatment on the second core body (2) to enable the fitting block (11) to be inserted into the receiving portion (21) ; inserting the fitting block (11) on the first core body (1) into the receiving portion (21) on the second core body (2) to assemble a sand core; performing a cooling treatment on the sand core to enable the receiving portion (21) to tightly hold the fitting block (11).

2. A method of making a sand core according to claim 1 wherein, The first core body (1) and the second core body (2) are both prepared by using inorganic resin sand.

3. A method of making a sand core according to claim 2 wherein, The second core body (2) is prepared after the first core body (1) is cooled.

4. A method of making a sand core according to claim 2 wherein, The sand core is hollow.

5. A method of making a sand core as defined in claim 1, wherein, The receiving portion (21) is shaped in accordance with the outer contour of the second core body (2).

6. A method of making a sand core as defined in claim 1, wherein, A step surface (211) is provided on the sidewall of the receiving portion (21), and a protruding block (111) corresponding to the step surface (211) is provided on the fitting block (11).

7. A method of making a sand core according to claim 6 wherein, A limiting slot (212) is provided on the step surface (211), and a limiting block (112) is provided on the fitting block (11), the limiting block (112) being capable of being embedded and clamped in the limiting slot (212).

8. A method of making a sand core according to claim 7 wherein, A compensation hole (213) is provided on the step surface (211) and is in communication with the limiting slot (212). 9.A sand core preparation device for preparing a sand core by the sand core preparation method according to any one of claims 1-8, the sand core preparation device comprising: a first mold comprising a first cavity and a first forming portion corresponding to the fitting block (11) in the first cavity, the first mold being configured to prepare the first core body (1) from sand material in the first cavity; a second mold comprising a second cavity and a second forming portion corresponding to the receiving portion (21) in the second cavity, the second mold being configured to prepare the second core body (2) from sand material in the second cavity and being configured to perform a heating treatment on the prepared second core body (2). 10.A sand core prepared according to the sand core preparation method according to any one of claims 1-8.

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