Sand core structure for differential shell and casting method
By designing the sand core structure for differential shells and optimizing the casting method, the problems of dimensional deviation and dynamic balance in the production of differential shell castings are solved, achieving more efficient production and lower defect risks.
Patent Information
- Application Number
- CN202510136713.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-07
- Publication Date
- 2025-05-06
AI Technical Summary
During the production process of existing differential shell castings, the accumulation of dimensional deviations leads to unqualified dynamic balance inspection, and conventional methods fail to effectively solve the problems of assembly accuracy and equipment coordination, and even cause defects such as sand squeezing and sand loss.
A sand core structure for differential shell is adopted, including the upper core head model, the sand core main model, the lower core head model, the side square core head model and the end-face round core head model. Through an integrated molding design, combined with the constraints on the core box deviation, the outer mold deformation amount and the clamping error deviation, the casting method is optimized to reduce dimensional deviation.
It effectively reduces the dimensional deviation of castings, improves dynamic balance performance, reduces the risk of defects such as sand squeezing and sand loss, and improves production efficiency.
Smart Images
Figure CN119927149A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of differential case casting, and in particular to a sand core structure and a casting method for a differential case. Background Art
[0002] If there is a large dimensional deviation in the casting of the differential housing, it will directly lead to failure in the dynamic balance performance test of the casting.
[0003] The actual production process of differential housing castings includes: accurately fixing the outer mold on the mold frame, shaping the outer mold to form a cavity; using the core box to make the sand core and accurately placing the sand core in the sand mold; and seamlessly closing the upper and lower sand molds and ensuring the alignment of all parts. Each link will cause dimensional deviation, which will eventually lead to the accumulation of dimensional deviations, and then cause the casting to fail the dynamic balance test.
[0004] In order to reduce the dimensional deviation in the casting production process, the industry usually adopts the method of reducing the gap between the sand core and the sand mold or strengthening the positioning of the sand core. However, the methods of reducing the gap between the sand core and the sand mold and strengthening the positioning of the sand core often fail to fully consider the assembly accuracy between the outer mold and the mold frame, the coordination between the equipment and the influence of the sand core structure, so that the dynamic balance problem is not effectively solved, and sometimes even causes defects such as sand squeezing and sand falling. Summary of the invention
[0005] The purpose of the present invention is to provide a sand core structure and casting method for a differential housing, which effectively solves the problem that existing methods such as reducing the gap between the sand core and the sand mold and strengthening the positioning of the sand core often fail to fully consider the assembly accuracy between the outer mold and the mold plate frame, the coordination between equipment and the influence of the sand core structure, so that the dynamic balance problem is not effectively solved, and sometimes even causes defects such as sand squeezing and sand falling.
[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:
[0007] In a first aspect, a sand core structure for a differential case is provided, comprising an upper core head model, a sand core main body model, a lower core head model, a side square core head model and an end face round core head model, wherein the sand core main body model is arranged on the bottom surface of the upper core head model, and the sand core main body model is used to form an inner cavity of the casting; the lower core head model is arranged on the bottom surface of the sand core main body model; there are two side square core head models, and the two side square core head models are relatively arranged on both sides of the sand core main body model; there are two end face round core head models, and the two end face round core head models are relatively arranged at both ends of the sand core main body model; wherein the upper core head model, the sand core main body model, the lower core head model, the side square core head model and the end face round core head model are integrally formed.
[0008] A further technical solution is: the height H of the upper core head model is ≤30mm; the cross-sectional area of the upper core head model gradually increases along the direction from the top surface of the upper core head model to the bottom surface of the upper core head model, and the angle between the generatrix of the upper core head model and the axis of the upper core head model is α≥1°; the size of the upper core head model is smaller than that of the upper mold, and is used to form a first gap between the outer wall of the upper core head model and the inner wall of the upper mold, and the first gap is greater than or equal to 0.5mm.
[0009] A further technical solution is: the height h of the lower core head model is ≤30mm; the cross-sectional area of the lower core head model gradually increases along the direction from the bottom surface of the lower core head model to the top surface of the lower core head model, and the angle between the generatrix of the lower core head model and the axis of the lower core head model is β≥1°; the size of the lower core head model is smaller than that of the lower mold, and is used to form a second gap between the outer wall of the lower core head model and the inner wall of the lower mold, and the second gap is greater than or equal to 0.5mm.
[0010] A further technical solution is: the side square core head model includes a first side square core head unit and a second side square core head unit; the first side square core head unit and the second side square core head unit are both connected to the side walls of the sand core main body model; the first side square core head unit is arranged on the top surface of the second side square core head unit, and the top surface of the first side square core head unit gradually approaches the top surface of the second side square core head unit along the direction away from the sand core main body model, and the first side square core head unit is used to fit in the upper mold; wherein, the size of the second side square core head unit is smaller than the size of the upper mold, and is used to form a third gap between the side wall of the second side square core head unit and the inner wall of the upper mold, and the third gap is less than or equal to 0.3mm.
[0011] A further technical solution is: the end face circular core head model includes a first end face circular core head unit, a second end face circular core head unit and a third end face circular core head unit; the first end face circular core head unit, the second end face circular core head unit and the third end face circular core head unit are all arranged on the end wall of the sand core main body model, and the first end face circular core head unit, the second end face circular core head unit and the third end face circular core head unit are arranged in sequence along the top surface of the sand core main body model toward the bottom surface of the sand core main body model; the first end face circular core head unit is used to form a cavity on the side of the differential housing; wherein the size of the first end face circular core head unit is smaller than the size of the upper mold, and is used to form a fourth gap between the outer wall of the first end face circular core head unit and the inner wall of the upper mold, and the fourth gap is greater than or equal to 0.5 mm; the cross-sectional area of the second end face circular core head unit, along the top surface of the second end face circular core head unit to the second end face circular core head unit The width D of the top surface of the second end face round core head unit is greater than or equal to 10, and the top surface of the second end face round core head unit is used to fit the inner wall of the upper mold; wherein the size of the second end face round core head unit is smaller than the size of the upper mold, and is used to form a fifth gap between the side wall of the second end face round core head unit and the inner wall of the upper mold, and the fifth gap is greater than or equal to 0.5mm; the cross-sectional area of the third end face round core head unit increases successively along the direction from the bottom surface of the third end face round core head unit to the top surface of the third end face round core head unit; the width d of the bottom surface of the third end face round core head unit is greater than or equal to 10; and the bottom surface of the third end face round core head unit is used to fit the inner wall of the lower mold; wherein the size of the third end face round core head unit is smaller than the size of the lower mold, and is used to form a sixth gap between the side wall of the third end face round core head unit and the inner wall of the lower mold, and the sixth gap is less than or equal to 0.3mm.
[0012] In a second aspect, a casting method is provided, the casting method being used for the sand core structure as described in the first aspect, the casting method comprising the following operations:
[0013] Use core boxes to make sand core structures;
[0014] The upper mold and the lower mold of the outer mold are installed on the upper mold plate frame and the lower mold plate frame respectively, and the upper mold, the lower mold, the upper mold plate frame and the lower mold plate frame are placed in the molding machine equipment for sand filling and compaction to obtain the upper cavity and the lower cavity;
[0015] The sand core structure is placed in the lower cavity, and the upper cavity and the lower cavity are molded together by a closing machine to obtain a differential housing casting cavity;
[0016] The differential case casting cavity is filled with molten metal, and after the molten metal is cooled, sand removal is performed to obtain the differential case casting.
[0017] A further technical solution is: the core box comprises a first core box part and a second core box part; and the misalignment between the first core box part and the second core box part when the mold is closed is less than or equal to 0.3 mm.
[0018] A further technical solution is that the deformation amounts of the upper die and the lower die of the outer die are both less than or equal to 0.3 mm.
[0019] A further technical solution is that the offset amount of the upper mold of the outer mold installed on the upper mold frame and the offset amount of the lower mold of the outer mold installed on the lower mold frame are both less than or equal to 0.2mm.
[0020] A further technical solution is that the misalignment between the upper cavity and the lower cavity is less than or equal to 0.3 mm.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] On the one hand, the core head model, the sand core main body model, the lower core head model, the side square core head model and the end round core head model are designed as a whole through an integrated molding method, so as to improve production efficiency and reduce the dimensional deviation problem caused by combining two sand cores in the prior art, thereby effectively improving the problem of unqualified dynamic balance of castings and reducing the risk of defects such as sand squeezing and sand falling.
[0023] On the other hand, by constraining the core box misalignment, outer mold deformation, outer mold misalignment, and mold closing misalignment, it is hoped to effectively reduce the dimensional deviation of the differential case casting, thereby effectively improving the problem of unqualified dynamic balance of the differential case casting, and reducing the risk of defects such as sand extrusion and sand falling. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 This is a schematic diagram of the front view of a sand core structure for a differential housing in this embodiment;
[0025] Figure 2 This is a schematic diagram of a top view of a sand core structure for a differential housing in this embodiment;
[0026] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle;
[0027] Figure 4 It is a side view structural schematic diagram of a sand core structure for a differential housing in this embodiment;
[0028] Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure at the middle BB;
[0029] Figure 6 Schematic diagram of a casting method in this embodiment.
[0030] Marks and corresponding parts names in the attached drawings:
[0031] 1-upper core head model; 2-sand core main body model; 3-lower core head model;
[0032] 4-side square core head model; 41-first side square core head unit; 42-second side square core head unit;
[0033] 5-end face round core head model; 51-first end face round core head unit; 52-second end face round core head unit; 53-third end face round core head unit. DETAILED DESCRIPTION
[0034] The present invention will be further described below in conjunction with the accompanying drawings.
[0035] Example 1
[0036] This embodiment provides a sand core structure for a differential housing, such as Figure 1-Figure 5 As shown, it includes an upper core head model 1, a sand core main body model 2, a lower core head model 3, a side square core head model 4 and an end face round core head model 5, wherein the sand core main body model 2 is arranged on the bottom surface of the upper core head model 1, and the sand core main body model 2 is used to form an inner cavity of a casting; the lower core head model 3 is arranged on the bottom surface of the sand core main body model 2; there are two side square core head models 4, and the two side square core head models 4 are relatively arranged on both sides of the sand core main body model 2; there are two end face round core head models 5, and the two end face round core head models 5 are relatively arranged at the two ends of the sand core main body model 2; wherein the upper core head model 1, the sand core main body model 2, the lower core head model 3, the side square core head model 4 and the end face round core head model 5 are integrally formed.
[0037] Exemplarily, during the implementation process, the sand core main body model 2 is used to form the inner cavity of the casting, and the structure of the sand core main body model 2 is determined by the structure of the substitute casting product, which is not specifically limited here. The upper core head model 1 is integrally formed on the top surface of the sand core main body model 2, the lower core head model 3 is integrally formed on the bottom surface of the sand core main body model 2, the two side square core head models 4 are symmetrically connected to the two sides of the sand core main body model 2 by one-side molding, and the two end round core head models 5 are stacked and connected to the two ends of the sand core main body model 2 by integral molding.
[0038] The core head model, the sand core main body model 2, the lower core head model 3, the side square core head model 4 and the end round core head model 5 are designed as a whole by an integrated molding method. It is expected to improve production efficiency and reduce the dimensional deviation problem caused by combining two sand cores in the prior art, thereby effectively improving the problem of unqualified dynamic balance of castings, and reducing the risk of defects such as sand squeezing and sand falling.
[0039] Example 2
[0040] In order to further improve the problem of unqualified dynamic balance of castings. Figure 3 As shown, on the basis of the above-mentioned embodiment 1, in this embodiment, the height H of the upper core head model 1 is ≤30mm; the cross-sectional area of the upper core head model 1 gradually increases along the direction from the top surface of the upper core head model 1 to the bottom surface of the upper core head model 1, and the angle between the generatrix of the upper core head model 1 and the axis of the upper core head model 1 is α≥1°; the size of the upper core head model 1 is smaller than that of the upper mold, and is used to form a first gap between the outer wall of the upper core head model 1 and the inner wall of the upper mold, and the first gap is greater than or equal to 0.5mm.
[0041] Exemplarily, during the implementation process, the height H of the upper core head model 1 does not exceed 30 millimeters (H≤30mm). Preferably, the height H of the upper core head model 1 is 10mm. The upper core head model 1 is in the shape of a truncated cone with a cross-sectional area gradually increasing from the top surface of the upper core head model 1 to the bottom surface of the upper core head model 1. And the angle αα between the generatrix of the upper core head model 1 and the axis is ≥1°. The size of the upper core head model 1 is smaller than the size of the upper mold, so that the first gap formed between the outer wall of the upper core head model 1 and the inner wall of the upper mold is ≥0.5mm. In other words, a first gap with a width greater than or equal to 0.5mm can be formed between the top surface of the upper core head model 1 and the inner wall of the upper mold, as well as between the side wall of the upper core head model 1 and the inner wall of the upper mold. Preferably, the first gap is 1.0mm. By constraining the size of the upper core head model 1, it is expected to significantly reduce the imbalance factor caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0042] Example 3
[0043] In order to further improve the problem of unqualified dynamic balance of castings. Figure 3 As shown, on the basis of the above-mentioned embodiment 1, in this embodiment, the height h of the lower core head model 3 is ≤30mm; the cross-sectional area of the lower core head model 3 gradually increases along the direction from the bottom surface of the lower core head model 3 to the top surface of the lower core head model 3, and the angle between the generatrix of the lower core head model 3 and the axis of the lower core head model 3 is β ≥1°; the size of the lower core head model 3 is smaller than that of the lower mold, and is used to form a second gap between the outer wall of the lower core head model 3 and the inner wall of the lower mold, and the second gap is greater than or equal to 0.5mm.
[0044] Exemplarily, during the implementation process, the height h of the lower core head model 3 does not exceed 30 millimeters (h≤30mm). Preferably, the height h of the lower core head model 3 is 10mm. The lower core head model 3 is in the shape of a truncated cone with a cross-sectional area gradually increasing from the bottom surface of the lower core head model 3 to the top surface of the upper core head model 1. And the angle β between the generatrix of the lower core head model 3 and the axis is ≥1°. The size of the lower core head model 3 is smaller than the size of the lower mold, so that the second gap formed between the outer wall of the lower core head model 3 and the inner wall of the lower mold is ≥0.5mm. In other words, a second gap with a width greater than or equal to 0.5mm can be formed between the bottom surface of the lower core head model 3 and the inner wall of the lower mold, and between the side wall of the lower core head model 3 and the inner wall of the upper mold. Preferably, the second gap is 1.0mm. By constraining the size of the lower core head model 3, it is expected to significantly reduce the imbalance factor caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0045] Example 4
[0046] In order to further improve the problem of unqualified dynamic balance of castings. Figure 3 As shown, on the basis of the above-mentioned embodiment 1, in this embodiment, the side square core head model 4 includes a first side square core head unit 41 and a second side square core head unit 42; the first side square core head unit 41 and the second side square core head unit 42 are both connected to the side wall of the sand core main body model 2; the first side square core head unit 41 is arranged on the top surface of the second side square core head unit 42, and the top surface of the first side square core head unit 41 gradually approaches the top surface of the second side square core head unit 42 along the direction away from the sand core main body model 2, and the first side square core head unit 41 is used to fit in the upper mold; wherein, the size of the second side square core head unit 42 is smaller than the size of the upper mold, and is used to form a third gap between the side wall of the second side square core head unit 42 and the inner wall of the upper mold, and the third gap is less than or equal to 0.3mm.
[0047] Exemplarily, during implementation, the above-mentioned side square core head model 4 includes a first side square core head unit 41 and a second side square core head unit 42. The first side square core head unit 41 and the second side square core head unit 42 are both connected to the side wall of the sand core main body model 2 by means of one-piece molding. Among them, the first side square core head unit 41 is connected to the top surface of the second side square core head unit 42 by means of one-piece molding, and the top surface of the first side square core head unit 41 gradually approaches the top surface of the second side facing core head unit in the direction away from the sand core main body model 2. And the first side square core head unit 41 is used to fit in the upper mold. In other words, the top surface of the first side square core head unit 41 and the side wall of the first side square core head unit 41 are both in contact with the inner wall of the upper mold (that is, the gap between the first side square core head unit 41 and the upper mold is 0 mm).
[0048] The top surface of the second side square core head unit 42 and the bottom surface of the second side square core head unit 42 are both in contact with the inner wall of the upper mold (the gap between the top surface of the second side square core head unit 42 and the upper mold, and the gap between the bottom surface of the second side square core head unit 42 and the upper mold are both 0mm). And the size of the second side square core head unit 42 is smaller than the size of the upper mold, so that the third gap formed between the side wall of the second side square core head unit 42 and the inner wall of the lower mold is ≤0.3mm. Preferably, the third gap is 0.15mm. By constraining the sizes of the first side square core head unit 41 and the second side square core head unit 42, it is expected to significantly reduce the imbalance factors caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0049] Example 5
[0050] In order to further improve the problem of unqualified dynamic balance of castings. Figure 5As shown, on the basis of the above-mentioned embodiment 1, in this embodiment, the end face round core head model 5 includes a first end face round core head unit 51, a second end face round core head unit 52 and a third end face round core head unit 53; the first end face round core head unit 51, the second end face round core head unit 52 and the third end face round core head unit 53 are all arranged on the end wall of the sand core main body model 2, and the first end face round core head unit 51, the second end face round core head unit 52 and the third end face round core head unit 53 are arranged in sequence along the top surface of the sand core main body model 2 toward the bottom surface of the sand core main body model 2; the first end face round core head unit 51 is used to form a cavity on the side of the differential housing; wherein the size of the first end face round core head unit 51 is smaller than the size of the upper mold, and is used to form a fourth gap between the outer wall of the first end face round core head unit 51 and the inner wall of the upper mold, and the fourth gap is greater than or equal to 0.5 mm; the cross-sectional area of the second end face round core head unit 52, along the top surface of the second end face round core head unit 52 The second end face round core head unit 52 has a width D of ≥10 on the top surface, and the top surface of the second end face round core head unit 52 is used to fit the inner wall of the upper mold; wherein the size of the second end face round core head unit 52 is smaller than the size of the upper mold, and is used to form a fifth gap between the side wall of the second end face round core head unit 52 and the inner wall of the upper mold, and the fifth gap is greater than or equal to 0.5 mm; the cross-sectional area of the third end face round core head unit 53 is The width d of the bottom surface of the third end face round core head unit 53 increases successively from the bottom surface of the third end face round core head unit 53 to the top surface of the third end face round core head unit 53; the bottom surface of the third end face round core head unit 53 is ≥10; and the bottom surface of the third end face round core head unit 53 is used to fit on the inner wall of the lower mold; wherein the size of the third end face round core head unit 53 is smaller than that of the lower mold, and is used to form a sixth gap between the side wall of the third end face round core head unit 53 and the inner wall of the lower mold, and the sixth gap is less than or equal to 0.3mm.
[0051] Exemplarily, in the implementation process, the end face round core head model 5 includes a first end face round core head unit 51 , a second end face round core head unit 52 and a third end face round core head unit 53 .
[0052] The first end face round core head unit 51, the second end face round core head unit 52 and the third end face round core head unit 53 are all connected to the end wall of the sand core main body model 2 by means of integral molding. The first end face round core head unit 51, the second end face round core head unit 52 and the third end face round core head unit 53 are arranged in sequence along the direction from the top surface of the sand core main body model 2 to the bottom surface of the sand core main body model 2. The bottom surface of the first end face round core head unit 51 is connected to the top surface of the second end face round core head unit 52 by means of integral molding, and the bottom surface of the second end face round core head unit 52 is connected to the top surface of the third end face round core head unit 53 by means of integral molding.
[0053] Among them, the first end face round core head unit 51 is used to form a cavity on the side of the differential housing. The size of the first end face round core head unit 51 is smaller than the size of the upper mold, so that the fourth gap formed between the outer wall of the first end face round core head unit 51 and the inner wall of the upper mold is ≥0.5mm. In other words, a fourth gap with a width greater than or equal to 0.5mm is formed between the top surface of the first end face round core head unit 51 and the inner wall of the upper mold, as well as between the side wall of the top surface of the first end face round core head unit 51 and the inner wall of the upper mold. Preferably, the fourth gap is 0.5mm. By constraining the size of the first end face round core head unit 51, it is expected to significantly reduce the imbalance factor caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0054] The second end face round core head unit 52 is a truncated cone structure whose cross-sectional area gradually increases from the top surface of the second end face round core head unit 52 to the bottom surface of the second end face round core head unit 52. The top surface width D of the second end face round core head unit 52 is ≥10, and the top surface of the second end face round core head unit 52 is used to fit the inner wall of the upper mold (the gap between the top surface of the second end face round core head unit 52 and the inner wall of the upper mold is 0mm). The size of the second end face round core head unit 52 is smaller than the size of the upper mold, so that the fifth gap formed between the side wall of the second end face round core head unit 52 and the inner wall of the upper mold is ≥0.5mm. Preferably, the fifth gap is 0.5mm. By constraining the size of the second end face round core head unit 52, it is expected to significantly reduce the imbalance factor caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0055] The third end face round core head unit 53 is a truncated cone structure whose cross-sectional area gradually increases from the bottom surface of the third end face round core head unit 53 to the top surface of the third end face round core head unit 53. The bottom surface width d of the third end face round core head unit 53 is ≥10, and the bottom surface of the third end face round core head unit 53 is used to fit the inner wall of the lower mold (the gap between the top surface of the third end face round core head unit 53 and the inner wall of the lower mold is 0mm). The size of the third end face round core head unit 53 is smaller than the size of the lower mold, so that the sixth gap formed between the side wall of the third end face round core head unit 53 and the inner wall of the lower mold is ≥0.5mm. Preferably, the sixth gap is 0.5mm. By constraining the size of the third end face round core head unit 53, it is expected to significantly reduce the imbalance factor caused by manufacturing tolerances, and further improve the problem of unqualified dynamic balance of castings, so as to reduce the risk of defects such as sand squeezing and sand falling.
[0056] Example 6
[0057] This embodiment provides a casting method, which is used for the sand core structure described in any one of Embodiments 1 to 5. Figure 6 As shown, the casting method includes the following operations:
[0058] S100. Making a sand core structure using a core box;
[0059] In this embodiment, the core box includes a first core box part and a second core box part; the misalignment between the first core box part and the second core box part when the mold is closed is less than or equal to 0.3 mm.
[0060] Exemplarily, during implementation, the core box includes a first core box part and a second core box part. The core box may adopt an upper-lower structure including the first core box part (upper part) and the second core box part (lower part), or a left-right structure including the first core box part (left part) and the second core box part (right part).
[0061] The first core box part and the second core box part are combined, and the first core box part and the second core box part are positioned by using pins and pin sleeves, so as to form the shape of the sand core structure by using the cavity inside the core box.
[0062] S200. The upper and lower molds of the outer mold are installed on the upper and lower mold frames, and the upper and lower molds, the upper and lower mold frames are placed in the molding machine equipment for sand filling and compaction to obtain the upper and lower mold cavities;
[0063] In this embodiment, the deformation amounts of the upper mold and the lower mold of the outer mold are both less than or equal to 0.3 mm.
[0064] In this embodiment, the offset amount of the upper mold of the outer mold installed on the upper mold frame and the offset amount of the lower mold of the outer mold installed on the lower mold frame are both less than or equal to 0.2 mm.
[0065] Exemplarily, in the implementation process, the outer mold includes an upper mold and a lower mold. The upper mold is placed on the upper mold frame, and the upper mold and the upper mold frame are positioned by pins and pin sleeves. The lower mold is placed on the lower mold frame, and the lower mold and the lower mold frame are positioned by pins and pin sleeves. The upper mold, the lower mold, the upper mold frame and the lower mold frame are placed together in a molding machine, and sand is filled and compacted to obtain an upper cavity and a lower cavity.
[0066] S300. Place the sand core structure into the lower cavity, and use a closing machine to close the upper cavity and the lower cavity to obtain a differential housing casting cavity;
[0067] Exemplarily, during the implementation process, a sand core is placed in the lower cavity, and a closing machine is used to close the upper cavity and the lower cavity, and pins and pin sleeves are used to position the upper cavity and the lower cavity to obtain a differential case casting cavity.
[0068] S400. Fill the differential case casting cavity with molten metal, and after the molten metal is cooled, perform sand removal to obtain the differential case casting.
[0069] For example, during the implementation process, molten metal is poured into the differential case casting cavity until the molten metal fills the remaining cavity inside the differential case casting cavity. Then, after the molten metal cools, the sand is cleaned to obtain the differential case casting.
[0070] By constraining the core box misalignment, outer mold deformation, outer mold misalignment, and mold closing misalignment, it is hoped that the dimensional deviation of the differential case casting can be effectively reduced, thereby effectively improving the problem of unqualified dynamic balance of the differential case casting and reducing the risk of defects such as sand extrusion and sand falling.
[0071] Although the present invention is described herein with reference to a number of illustrative embodiments of the present invention, it will be appreciated that those skilled in the art may devise many other modifications and implementations that fall within the scope and spirit of the principles disclosed herein. More specifically, within the scope of the present disclosure, drawings, and claims, a variety of variations and improvements may be made to the components and / or layout of the subject combination layout. In addition to variations and improvements made to the components and / or layout, other uses will also be apparent to those skilled in the art.
Claims
1. A sand core structure for a differential case, characterized in that: include: Upper core head model (1); A sand core main body model (2), wherein the sand core main body model (2) is arranged on the bottom surface of the upper core head model (1), and the sand core main body model (2) is used to form an inner cavity of the casting; A lower core head model (3), wherein the lower core head model (3) is arranged on the bottom surface of the sand core main body model (2); A side square core head model (4), wherein the number of the side square core head models (4) is two, and the two side square core head models (4) are arranged on two sides of the sand core main body model (2) opposite to each other; An end face round core head model (5), wherein the number of the end face round core head models (5) is two, and the two end face round core head models (5) are arranged at two ends of the sand core main body model (2) opposite to each other; The upper core head model (1), the sand core main body model (2), the lower core head model (3), the side square core head model (4) and the end round core head model (5) are integrally formed.
2. The sand core structure according to claim 1, characterized in that: The height H of the upper core head model (1) is ≤30 mm; The cross-sectional area of the upper core head model (1) gradually increases along the direction from the top surface of the upper core head model (1) to the bottom surface of the upper core head model (1), and the angle between the generatrix of the upper core head model (1) and the axis of the upper core head model (1) is α≥1°; The size of the upper core head model (1) is smaller than that of the upper mold, and is used to form a first gap between the outer wall of the upper core head model (1) and the inner wall of the upper mold, wherein the first gap is greater than or equal to 0.5 mm.
3. The sand core structure according to claim 1, characterized in that: The height h of the lower core head model (3) is ≤30 mm; The cross-sectional area of the lower core head model (3) gradually increases along the direction from the bottom surface of the lower core head model (3) to the top surface of the lower core head model (3), and the angle between the generatrix of the lower core head model (3) and the axis of the lower core head model (3) is β≥1°; The size of the lower core head model (3) is smaller than that of the lower mold, and is used to form a second gap between the outer wall of the lower core head model (3) and the inner wall of the lower mold, and the second gap is greater than or equal to 0.5 mm.
4. The sand core structure according to claim 1, characterized in that: The side square core head model (4) comprises a first side square core head unit (41) and a second side square core head unit (42); The first side square core head unit (41) and the second side square core head unit (42) are both connected to the side wall of the sand core main body model (2); The first side square core head unit (41) is arranged on the top surface of the second side square core head unit (42), the top surface of the first side square core head unit (41) gradually approaches the top surface of the second side square core head unit (42) along the direction away from the sand core main body model (2), and the first side square core head unit (41) is used to fit in the upper mold; The size of the second side square core head unit (42) is smaller than that of the upper mold, and is used to form a third gap between the side wall of the second side square core head unit (42) and the inner wall of the upper mold, and the third gap is less than or equal to 0.3 mm.
5. The sand core structure according to claim 1, characterized in that: The end face round core head model (5) comprises a first end face round core head unit (51), a second end face round core head unit (52) and a third end face round core head unit (53); The first end face round core head unit (51), the second end face round core head unit (52) and the third end face round core head unit (53) are all arranged on the end wall of the sand core main body model (2), and the first end face round core head unit (51), the second end face round core head unit (52) and the third end face round core head unit (53) are arranged in sequence along the direction from the top surface of the sand core main body model (2) to the bottom surface of the sand core main body model (2); The first end face round core head unit (51) is used to form a cavity on the side of the differential housing; The size of the first end face round core head unit (51) is smaller than that of the upper die, and is used to form a fourth gap between the outer wall of the first end face round core head unit (51) and the inner wall of the upper die, and the fourth gap is greater than or equal to 0.5 mm; The cross-sectional area of the second end face circular core head unit (52) increases in sequence along the direction from the top surface of the second end face circular core head unit (52) to the bottom surface of the second end face circular core head unit (52); the width D of the top surface of the second end face circular core head unit (52) is ≥10, and the top surface of the second end face circular core head unit (52) is used to fit on the inner wall of the upper mold; The size of the second end face round core head unit (52) is smaller than that of the upper die, and is used to form a fifth gap between the side wall of the second end face round core head unit (52) and the inner wall of the upper die, and the fifth gap is greater than or equal to 0.5 mm; The cross-sectional area of the third end face round core head unit (53) increases in sequence from the bottom surface of the third end face round core head unit (53) to the top surface of the third end face round core head unit (53); the width d of the bottom surface of the third end face round core head unit (53) is ≥ 10; and the bottom surface of the third end face round core head unit (53) is used to fit on the inner wall of the lower mold; The size of the third end face round core head unit (53) is smaller than that of the lower die, and is used to form a sixth gap between the side wall of the third end face round core head unit (53) and the inner wall of the lower die, and the sixth gap is less than or equal to 0.3 mm.
6. A casting method, the casting method being used for the sand core structure according to any one of claims 1 to 5, characterized in that: The casting method comprises the following operations: Use core boxes to make sand core structures; The upper mold and the lower mold of the outer mold are installed on the upper mold plate frame and the lower mold plate frame respectively, and the upper mold, the lower mold, the upper mold plate frame and the lower mold plate frame are placed in the molding machine equipment for sand filling and compaction to obtain the upper cavity and the lower cavity; The sand core structure is placed in the lower cavity, and the upper cavity and the lower cavity are molded together by a closing machine to obtain a differential housing casting cavity; The differential case casting cavity is filled with molten metal, and after the molten metal is cooled, sand removal is performed to obtain the differential case casting.
7. The casting method according to claim 6, characterized in that: The core box comprises a first core box part and a second core box part; The misalignment between the first core box part and the second core box part during mold closing is less than or equal to 0.3 mm.
8. The casting method according to claim 6, characterized in that: The deformation amounts of the upper mold and the lower mold of the outer mold are both less than or equal to 0.3 mm.
9. The casting method according to claim 6 or 8, characterized in that: The misalignment amount of the upper mold of the outer mold installed on the upper mold plate frame and the misalignment amount of the lower mold of the outer mold installed on the lower mold plate frame are both less than or equal to 0.2 mm.
10. The casting method according to claim 6, characterized in that: The misalignment between the upper cavity and the lower cavity is less than or equal to 0.3 mm.