Large casting sand core and core assembly method thereof

Abstract

The invention discloses a large casting sand core which comprises at least one sand core body, the sand core body comprises a first branch sand core and a second branch sand core which are divided by a parting surface, the sand core body is provided with a limiting hole which is perpendicular to the parting surface and used for limiting, and the limiting hole penetrates through the first branch sand core and the second branch sand core. The limiting hole is filled with resin sand, the limiting hole comprises a hole part and an end part which are communicated with each other, and the size of the end part of the limiting hole is larger than that of the hole part of the limiting hole. According to the large casting sand core, the fitting tightness of parting surfaces can be guaranteed, the step of cleaning burrs or burrs in a casting is reduced, the production efficiency is higher, the production cost is lower, and the quality of the casting is better. The invention further discloses a core assembling method of the large casting sand core.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a large casting sand core and a core assembly method thereof. Background Art

[0002] The sand cores of large and complex shell castings usually need to be divided into several parts for separate core making, and then the parts are cored in a certain order to complete the core assembly. The parting surfaces of the sand core, especially the parting surfaces in the vertical and horizontal directions, are very likely to form burrs and flashes on the inner surface of the casting due to loose fit or displacement due to the buoyancy of the molten metal. It is very difficult to clean the burrs or flashes inside large and complex shell castings, and it is even necessary to open holes in the already formed castings, clean the burrs or flashes, and then weld them, resulting in low labor productivity, increased production costs, and reduced overall casting performance. Summary of the invention

[0003] In view of this, the present invention provides a large casting sand core, which can ensure the tightness of the parting surface fit, reduce the steps of cleaning burrs or flashes inside the casting, and has higher production efficiency, lower production costs and better casting quality.

[0004] The invention also provides a core assembling method for large casting sand cores.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A large casting sand core comprises at least one sand core body, wherein the sand core body comprises a first sub-sand core and a second sub-sand core separated by a parting surface, the sand core body is provided with a limiting hole for limiting which is arranged perpendicular to the parting surface, the limiting hole passes through the first sub-sand core and the second sub-sand core, the limiting hole is filled with resin sand, the limiting hole comprises a hole portion and an end portion which are connected, and the end portion size of the limiting hole is larger than the hole portion size of the limiting hole.

[0007] Optionally, the side wall of the end of the limiting hole is a conical surface, and the small end of the conical surface is arranged close to the hole portion of the limiting hole;

[0008] Alternatively, the side wall of the end portion of the limiting hole is an arc-shaped surface, and the small end of the arc-shaped surface is arranged close to the hole portion of the limiting hole.

[0009] Optionally, a plurality of the limiting holes are provided on the sand core body, and a spacing between the limiting holes is 100 mm to 400 mm.

[0010] Optionally, the sand intake around the limiting hole is 20 mm to 200 mm.

[0011] Optionally, the maximum diameter of the end of the limiting hole is 20mm~50mm, the hole portion of the limiting hole is a cylindrical hole, the diameter of the hole portion of the limiting hole is 10mm~40mm, and the difference between the maximum diameter of the end of the limiting hole and the diameter of the hole portion of the limiting hole is 10mm.

[0012] Optionally, the first sub-sand core and the second sub-sand core are symmetrically arranged with respect to the parting plane;

[0013] An exhaust channel for exhausting the sand core is arranged on the parting surface of the sand core body. The exhaust channel is extended along the parting surface and does not intersect with the limiting hole.

[0014] Optionally, the cross section of the exhaust channel is circular, and the diameter of the cross section of the exhaust channel is 3 mm to 5 mm.

[0015] Optionally, it comprises a plurality of the sand core bodies spliced ​​together, and the exhaust passages on adjacent sand core bodies are connected.

[0016] It can be seen from the above technical scheme that the large casting sand core provided by the present invention is achieved by providing a connecting limit hole on the first and second sand cores on both sides of the parting surface, and the limit hole is set to a structure with an end size larger than the hole size, and self-hardening resin sand is filled in the limit hole. After the resin sand in the limit hole is hardened, it is equivalent to providing a locking structure in the limit hole, so as to avoid the first and second sand cores from moving away from each other, so that the first and second sand cores are tightly fitted at the parting surface position, and the positions of the first and second sand cores are more reliable, avoiding the displacement of the positions due to the loose fitting of the sand cores or the buoyancy of the molten metal, so that there is no gap between the first and second sand cores, avoiding the alloy liquid from flowing into the parting surface to form burrs and burrs, and the molding quality of the casting is better, saving the steps of cleaning the burrs or burrs inside the casting in the prior art, improving production efficiency, reducing production costs, and no need to open holes in the casting to clean defects such as burrs, and the overall performance of the casting is better.

[0017] The present invention also provides a core assembly method for a large casting sand core, comprising:

[0018] Group the sand cores, design the parting surface and make the mold, and make the sand core bodies of the sand core according to the mold;

[0019] The sand core body is assembled along the parting surface, and the reserved limiting holes are filled with resin sand to form a limiting structure. After the filled resin sand is hardened, the surface of the sand core body is polished and smoothed;

[0020] The cores are removed one by one according to the above steps, and finally the sand core body is assembled.

[0021] Optionally, an exhaust channel is reserved on the parting surface of the sand core body, and the exhaust channels between adjacent sand core bodies are connected.

[0022] The core assembly method of the large casting sand core of the present invention is used to assemble the above-mentioned large casting sand core, and thus has the advantages of the above-mentioned large casting sand core, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic cross-sectional view of the position of the limiting holes on the sand core body provided by one embodiment of the present invention;

[0025] Figure 2 for Figure 1 A schematic diagram of the structure after the resin sand filled in the limiting hole is hardened;

[0026] Figure 3 A schematic cross-sectional view of the position of the limiting holes on the sand core body provided by another embodiment of the present invention;

[0027] Figure 4 A schematic diagram of a partial cross-sectional structure of a first sand core provided in an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of a partial cross-sectional structure of a second sand core provided in an embodiment of the present invention;

[0029] Figure 6 A schematic structural diagram of a sand core body provided with an exhaust channel provided in an embodiment of the present invention;

[0030] Figure 7 A schematic structural diagram of a first sub-sand core provided with an exhaust channel provided in an embodiment of the present invention;

[0031] Figure 8 A schematic structural diagram of a second sub-sand core provided with an exhaust channel provided in an embodiment of the present invention;

[0032] Fig. 9 A schematic structural diagram of a casting formed by a sand core according to an embodiment of the present invention;

[0033] Fig.10 The embodiment of the present invention provides Fig. 9 Schematic diagram of the explosion structure of the sand core corresponding to the casting;

[0034] Fig.11 for Fig.10 Schematic diagram of the core assembly structure of the sand core.

[0035] in:

[0036] 1. Sand core,

[0037] 101. The first sand core,

[0038] 1011, a first tapered hole, 1012, a first sub-hole, 1013, a first sub-airflow channel,

[0039] 102. The second sand core,

[0040] 1021, a second tapered hole, 1022, a second sub-hole, 1023, a second sub-airflow channel,

[0041] 103. Limiting hole,

[0042] 104. Parting surface,

[0043] 105. Resin sand,

[0044] 106. Exhaust channel. DETAILED DESCRIPTION

[0045] The invention discloses a large-scale casting sand core, which can ensure the tightness of the parting surface fitting, reduces the steps of cleaning the burrs or flashes inside the casting, has higher production efficiency, lower production cost and better casting quality.

[0046] The invention also discloses a core assembling method for large-scale casting sand cores.

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Reference Figures 1 to 5The large casting sand core of the present invention comprises at least one sand core body 1, the sand core body 1 comprises a first sub-sand core 101 and a second sub-sand core 102 separated by a parting surface 104, and a limiting hole 103 for limiting arranged perpendicular to the parting surface 104 is arranged on the sand core body 1, the limiting hole 103 penetrates the first sub-sand core 101 and the second sub-sand core 102, and the limiting hole 103 is filled with resin sand 105. The limiting hole 103 comprises a hole portion and an end portion which are connected, and the size of the end portion of the limiting hole 103 is larger than the size of the hole portion of the limiting hole 103, so that the resin sand 105 in the limiting hole 103 forms a structure for limiting the first sub-sand core 101 and the second sub-sand core 102.

[0049] The resin sand 105 is self-hardening resin sand. The ends of the limiting hole 103 refer to both ends thereof.

[0050] The large casting sand core of the present invention is provided with a connecting limit hole 103 on the first and second part sand cores 101 and 102 on both sides of the parting surface 104, and the limit hole 103 is configured to have an end size larger than the hole size, and the limit hole 103 is filled with self-hardening resin sand 105. After the resin sand 105 in the limit hole 103 is hardened, it is equivalent to a locking structure provided in the limit hole 103, so as to prevent the first and second part sand cores 101 and 102 from moving away from each other, so that the first and second part sand cores 101 and 102 can be locked. The parting surface 104 is tightly fitted, and the positions of the first and second part sand cores 101 and 102 are more reliable, which avoids the displacement of the part sand cores due to loose fitting or the buoyancy of the molten metal, so that there is no gap between the first and second part sand cores 101 and 102, and the alloy liquid is prevented from flowing into the parting surface 104 to form burrs and flashes, so that the molding quality of the casting is better, and the step of cleaning the burrs or flashes inside the casting in the prior art is saved, thereby improving the production efficiency, reducing the production cost, and improving the overall quality of the casting.

[0051] In one embodiment, the side wall of the end of the limiting hole 103 is a conical surface, such as Figure 1 As shown, the small end of the conical surface is arranged close to the hole portion of the limiting hole 103. The diameter of the small end of the conical surface is the same as the diameter of the hole portion of the limiting hole 103. The parting surface 104 is arranged along the symmetric plane of the first sub-sand core 101 and the second sub-sand core 102, or the parting surface 104 is a plane arranged close to the symmetric plane of the first sub-sand core 101 and the second sub-sand core 102.

[0052] In another embodiment, the side wall of the end of the limiting hole 103 is an arc-shaped surface, such as Figure 3 As shown, the small end of the arc-shaped surface is arranged close to the hole portion of the limiting hole 103. The diameter of the small end of the arc-shaped surface is the same as the diameter of the hole portion of the limiting hole 103.

[0053] In order to improve the reliability of the fitting between the first sub-sand core 101 and the second sub-sand core 102, a plurality of limiting holes 103 are provided on the sand core body 1. The number of the limiting holes 103 is set by technicians in this field according to actual needs, and the spacing between the limiting holes 103 is 100mm to 400mm.

[0054] Specifically, Figure 4 As shown, the first sub-hole 1012 is provided on the first sub-core 101, and the end of the first sub-hole 1012 away from the second sub-core 102 is provided with a first tapered hole 1011, and the first sub-hole 1012 is connected to the first tapered hole 1011. Correspondingly, the second sub-core 102 is provided with a second sub-hole 1022, as shown in FIG. Figure 5 As shown, the end of the second sub-hole 1022 away from the first sub-core 101 is provided with a second tapered hole 1021, and the second tapered hole 1021 is connected with the second sub-hole 1022. The first sub-hole 1012 and the second sub-hole 1022 have the same aperture, and their positions correspond. The first sub-hole 1012 and the second sub-hole 1022 are spliced ​​into a limiting hole 103. The first tapered hole 1011 and the second tapered hole 1021 are symmetrically arranged about the parting surface 104.

[0055] In order to prevent the structure of the limiting hole 103 from affecting the outer contour of the sand core body 1, the sand intake around the limiting hole 103 is 20 mm to 200 mm. The sand intake refers to the distance from the edge of the hole to the outer surface of the sand core body 1 in the radial direction, so as to ensure the strength of the sand core body 1 around the limiting hole 103. It can be understood that the larger the aperture of the limiting hole 103, the greater the sand intake, and the smaller the aperture of the limiting hole 103, the smaller the sand intake.

[0056] Furthermore, the maximum diameter of the end of the limiting hole 103 is 20 mm to 50 mm, the hole portion of the limiting hole 103 is a cylindrical hole, and the diameter of the hole portion of the limiting hole 103 is 10 mm to 40 mm. In order to ensure the limiting strength of the end of the limiting hole 103 and avoid the structural strength of the entire core being affected by the structure of the limiting hole 103, the difference between the maximum diameter of the end of the limiting hole 103 and the diameter of the hole portion of the limiting hole 103 is 10 mm. If the difference between the maximum diameter of the end of the limiting hole 103 and the diameter of the hole portion of the limiting hole 103 is too small, the fitting force of the first sub-sand core 101 and the second sub-sand core 102 cannot be guaranteed. If the difference between the maximum diameter of the end of the limiting hole 103 and the diameter of the hole portion of the limiting hole 103 is too large, the structural strength of the sand core will be affected.

[0057] In order to improve the smoothness of the exhaust of the sand core body 1, at least one exhaust channel 106 is provided on the parting surface 104 of the sand core body 1. Figure 6As shown, the exhaust channel 106 is extended along the parting surface 104, so as to facilitate the exhaust of the gas in the sand core body 1. In order to prevent the exhaust channel 106 from affecting the limiting effect of the limiting hole 103, the exhaust channel 106 does not intersect with the limiting hole 103. In order to facilitate molding and to reduce the occurrence of concentrated force positions, the cross-section of the exhaust channel 106 is circular. In order to reduce the influence of the exhaust channel 106 on the structural strength of the sand core body 1, the diameter of the cross-section of the exhaust channel 106 is 3mm to 5mm. In order to facilitate the molding of the exhaust channel 106, as shown in FIG. Figure 7 As shown, a first sub-airflow channel 1013 is provided on the surface where the first sub-sand core 101 contacts the second sub-sand core 102. Figure 8 As shown, a second branch airflow channel 1023 is provided on the surface where the second branch sand core 102 contacts the first branch sand core 101. The first branch airflow channel 1013 and the second branch airflow channel 1023 are both semicircular channels, and the apertures of the first branch airflow channel 1013 and the second branch airflow channel 1023 are the same, and the arrangement positions of the two correspond, so that the first branch airflow channel 1013 and the second branch airflow channel 1023 are spliced ​​into an exhaust channel 106. When the casting sand core includes a plurality of sand core bodies 1 spliced ​​together, the exhaust channels 106 on adjacent sand core bodies 1 are connected to establish an overall smooth exhaust system.

[0058] In one embodiment, if Fig. 9 This is a schematic diagram of a large aluminum alloy bracket casting. Fig.10 for Fig. 9 A schematic diagram of the structure in which the sand core of the casting is divided into multiple sand core bodies 1, and a schematic diagram of the parting surfaces of each sand core body 1. Fig.10 In the figure, the entire sand core of the casting is divided into six sand core bodies 1, namely A, B, C, D, E and F, and each sand core body 1 includes two sub-sand cores divided along the parting surface. Fig.11 for Fig.10 The schematic diagram of the structure of the six sand core bodies after the core is assembled. Fig.11 A limiting hole 103 is provided on each sand core body 1.

[0059] The large casting sand core of the present invention can reduce or even eliminate the burrs or flashes on the inner surface of large shell castings, reduce the steps of cleaning the burrs or flashes, avoid damaging the structure of the castings to clean the burrs or flashes on the inner surface, improve productivity, and reduce production costs. By providing the exhaust channel 106, it is prevented that the gas enters the alloy liquid of the casting through the surface of the sand core, prevents the casting from forming defects such as invasive pores and inclusions, and improves the metallurgical quality of the casting.

[0060] The present invention also provides a core assembly method for large casting sand cores, including: grouping sand cores, designing parting surfaces and making molds, and making each sand core body 1 of the sand core according to the mold, with a limit hole 103 reserved on the sand core body 1, and an exhaust channel 106 reserved on the parting surface 104. The sand core body 1 is assembled along the parting surface 104, and the reserved limit hole 103 is filled with resin sand 105 to form a limit structure. After the filled resin sand 105 is hardened, the surface of the sand core body 1 is polished and smoothed, and each sand core is processed according to the above processing steps. All sand core bodies 1 are spliced ​​into the entire sand core. Among them, an exhaust channel 106 for exhaust is provided on the parting surface 104 of the sand core body 1, and the exhaust channels 106 of adjacent sand core bodies 1 are connected to facilitate the discharge of gas in the sand core.

[0061] The large casting sand core of the present invention is suitable for casting large and complex hanger-type structural parts. Large refers to a length of not less than 2.5m and a weight of not less than 500kg; complex refers to a complex structure, large wall thickness differences, and a wing-shaped structure that conforms to aerodynamic design; hanger-type structural parts refer to structural parts composed of multiple load-bearing beams, and the load-bearing beams are connected by wing-shaped structures, which are usually placed externally on aircraft and used to hang or carry items.

[0062] In the description of this solution, it should be understood that the terms "upper", "lower", "vertical", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this solution.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this solution, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0064] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A large casting sand core, characterized in that: The invention comprises at least one sand core body, wherein the sand core body comprises a first sub-sand core and a second sub-sand core separated by a parting surface, and the sand core body is provided with a limiting hole for limiting which is arranged perpendicular to the parting surface, and the limiting hole passes through the first sub-sand core and the second sub-sand core, and the limiting hole is filled with resin sand, and the limiting hole comprises a hole portion and an end portion which are connected, and the end portion size of the limiting hole is larger than the hole portion size of the limiting hole.

2. The large casting sand core according to claim 1, characterized in that: The side wall of the end of the limiting hole is a conical surface, and the small end of the conical surface is arranged close to the hole portion of the limiting hole; Alternatively, the side wall of the end portion of the limiting hole is an arc-shaped surface, and the small end of the arc-shaped surface is arranged close to the hole portion of the limiting hole.

3. The large casting sand core according to claim 1 or 2, characterized in that: The sand core body is provided with a plurality of the limiting holes, and the spacing between the limiting holes is 100 mm to 400 mm.

4. The large casting sand core according to claim 1 or 2, characterized in that: The sand intake around the limiting hole is 20mm to 200mm.

5. The large casting sand core according to claim 1, characterized in that: The maximum diameter of the end of the limiting hole is 20mm~50mm, the hole portion of the limiting hole is a cylindrical hole, the diameter of the hole portion of the limiting hole is 10mm~40mm, and the difference between the maximum diameter of the end of the limiting hole and the diameter of the hole portion of the limiting hole is 10mm.

6. The large casting sand core according to claim 1, characterized in that: The first sub-sand core and the second sub-sand core are symmetrically arranged with respect to the parting plane; An exhaust channel for exhausting the sand core is arranged on the parting surface of the sand core body. The exhaust channel is extended along the parting surface and does not intersect with the limiting hole.

7. The large casting sand core according to claim 6, characterized in that: The cross section of the exhaust channel is circular, and the diameter of the cross section of the exhaust channel is 3 mm to 5 mm.

8. The large casting sand core according to claim 6, characterized in that: It comprises a plurality of sand core bodies spliced ​​together, and the exhaust passages on adjacent sand core bodies are connected.

9. A method for assembling a large casting sand core, characterized in that: include: Group the sand cores, design the parting surface and make the mold, and make the sand core bodies of the sand core according to the mold; The sand core body is assembled along the parting surface, and the reserved limiting holes are filled with resin sand to form a limiting structure. After the filled resin sand is hardened, the surface of the sand core body is polished and smoothed; The cores are removed one by one according to the above steps, and finally the sand core body is assembled.

10. The method for assembling a large casting sand core according to claim 9, characterized in that: An exhaust channel is reserved on the parting surface of the sand core body, and the exhaust channels between adjacent sand core bodies are connected.

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