Vertical parting casting sand mold for shaft hole type castings

Abstract

The invention relates to the technical field of casting, in particular to a vertical parting casting sand mold for shaft hole castings, which comprises a first mold and a second mold which are matched with each other, a hemispherical elastic element is arranged in a shaft hole of a first metal mold of the second mold, and the center line of the elastic element is positioned on the axis of the shaft hole of the first metal mold; the second mold is correspondingly provided with a second pouring cup, a second metal mold and a dead head; and the dead head is arranged corresponding to the longitudinal pouring gate on the first mold. The semispherical elastic element is arranged in the metal shaft hole of the first mold, and during demolding, the elastic element generates certain thrust on the sand mold on the inner wall of the metal shaft hole under the action of resilience force of the elastic element, so that the viscous resistance between the sand mold and the inner wall of the first metal shaft hole is reduced, the demolding resistance is reduced, and the quality of the sand mold is ensured; therefore, the quality of the cast piece is ensured. According to the invention, the design is reasonable, the damage to the mold is low, the original mold or sand shooting equipment does not need to be greatly improved, and the production cost of an enterprise is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a vertical parting sand casting mould for shaft hole type castings. Background Art

[0002] In vertically parted casting, the mold is formed with a vertical parting plane and is typically composed of two halves (e.g., left and right). During molding, the two halves are closed to form a cavity, into which molten metal is poured through the pouring gate. After solidification, the two halves are separated to remove the casting.

[0003] like Figure 1 As shown, the casting includes an axial hole and a connecting arm, which connects to the outer wall of the axial hole to form an arc-shaped casting. Although the casting structure is simple, it is equipped with a relatively large axial hole. When using vertical parting casting, various defects often appear on the inner wall of the axial hole, making it difficult to meet actual requirements and resulting in an increased casting scrap rate. After long-term research and improvement, it was found that the main causes of casting failure are unreasonable runner system design and the separation of the passively demolded sand mold from the mold during the sand shooting machine's sand mold release process. Specifically, after the sand shooting machine forms the sand mold using the casting mold, the mold and sand mold are separated. The driving device actively separates the mold half (the active mold) from the sand mold, while the other half (the passive mold) is pushed to the conveyor. The conveyor drives the sand mold, passively separating the sand mold from the other half. The other half is then pulled back by the driving device. During this process, when the sand mold is passively separated from the half mold, viscous resistance is easily generated between the sand mold and the mold, resulting in poor demolding, affecting the quality of the sand mold, and thus reducing the quality of the casting. Summary of the Invention

[0004] The purpose of the present invention is to address the shortcomings of the existing technology and provide a vertically parted sand mold for castings with axial holes. By arranging an elastic element in the axial hole of the metal mold of the passive mold, the viscous resistance between the sand mold and the passive mold is reduced or avoided, so that the sand mold can be demolded smoothly and the quality of the sand mold and the casting is guaranteed.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a vertical parting sand mold for shaft hole castings, comprising a first mold and a second mold that cooperate with each other, The first mold includes a first base plate, the upper surface of which is provided with a plurality of first metal molds, a first pouring cup, and a runner system, the first pouring cup being located above the runner system, the runner system including a horizontal runner and a vertical runner, the vertical runner being vertically arranged, the first metal molds being arranged in an array, with adjacent first metal molds being symmetrically arranged, the axis of the axial hole of the first metal mold being perpendicular to the first base plate, an elastic element being provided inside the axial hole of the first metal mold, the elastic element being hemispherical, the center of the elastic element being located on the axis of the axial hole of the first metal mold; The second mold is provided with a second base plate, and the upper surface of the second base plate is provided with a second pouring cup and a second metal mold, the second pouring cup is provided corresponding to the first pouring cup, the second metal mold is provided corresponding to the first metal mold, and a riser is provided between two adjacent second metal molds, and the riser is provided corresponding to the longitudinal runner of the runner system.

[0006] Furthermore, the distance between the outer wall of the elastic element and the inner wall of the shaft hole of the first metal mold is not less than 5 mm, so as to avoid the sand mold of the inner wall of the shaft hole of the sand mold being too thin, resulting in the sand mold strength of the inner wall of the shaft hole being too low, and causing the sand mold to collapse after pouring metal.

[0007] Furthermore, the elastic element is made of high-temperature resistant silicone, and the spherical cap height of the elastic element is 0.5-1.1 times the spherical radius.

[0008] Furthermore, the Shore hardness of the elastic element is 60-90 Shore A, and the molecular chain cross-linking density is high, which makes the elastic element more structurally stable at higher temperatures; at the same time, when the sand mold is separated from the first mold, the elastic element has a higher resilience, effectively reducing the demolding resistance between the sand mold and the first mold.

[0009] Furthermore, the surface of the elastic element is provided with a concave-convex texture, which can destroy the continuity between the contact surface of the sand mold and the elastic element surface, reduce the surface adhesion between the sand mold and the elastic element, facilitate the separation of the elastic element from the sand mold, and reduce the demolding resistance.

[0010] Furthermore, an arc-shaped groove is provided at the bottom of the first metal mold shaft hole, and the radius of the arc-shaped groove is 0.5-1 mm larger than the radius of the elastic element, providing elastic deformation space for the contraction deformation of the elastic element.

[0011] Furthermore, the top surface height of the riser is lower than the center height of the axial hole of the second metal mold. During the pouring process, the molten metal preferentially fills the axial hole. The riser serves as a subsequent shrinkage feeding channel, thereby improving the shrinkage feeding efficiency of the riser and reducing casting defects such as shrinkage cavities.

[0012] Furthermore, the riser is located outside the arc of the second metal mold, and the sub-gate of the riser is located below the axial hole, which is conducive to improving the shrinkage compensation efficiency of the riser and reducing the problems of air holes, inclusions and shrinkage holes in the casting.

[0013] Furthermore, the thickness of the longitudinal runner is 0.8-1.1 times the thickness of the first metal mold, and the thickness of the riser is 0.8-1.1 times the thickness of the second metal mold, which is beneficial to improving the shrinkage feeding efficiency of the casting and ensuring the fluidity of the molten metal.

[0014] Furthermore, at least two rows of second metal molds arranged in the transverse direction are provided on the second bottom plate, and the number of second metal molds in each row is at least two and is evenly spaced along the longitudinal direction, which is beneficial to improving the production efficiency of castings and reducing the variability of castings; the longitudinal runner is a complete straight cylinder structure that runs through all rows of second metal molds, and the center line of the longitudinal runner is perpendicular to the arrangement direction of each row of second metal molds, and the risers between each row of second metal molds are directly connected to the longitudinal runner; the cross-section of the longitudinal runner is square, and the longitudinal runner is provided with a draft angle of 1-3°, which is beneficial to the uniform diversion of molten metal from the longitudinal runner to each riser, reducing the flow resistance of molten metal, improving the shrinkage compensation efficiency of castings, and reducing shrinkage holes in castings.

[0015] The beneficial effects of the present invention are: 1. This invention significantly improves the demolding performance of the sand mold from the inner wall of the first metal mold's axial hole by placing an elastic element within the passive mold's metal mold axial hole. The spherical or spherical cap-shaped elastic element exhibits excellent geometric symmetry and uniform force distribution, ensuring the quality of the sand mold and, consequently, the casting. When the first mold (passive mold) is separated from the sand mold, the compressed elastic element, under its own resilience, exerts a thrust on the sand mold, effectively weakening the adhesion between the sand mold and the mold, significantly reducing demolding resistance. Its unique hemispherical structural design significantly reduces demolding resistance between the sand mold and the elastic element, facilitating separation and ensuring a smooth and efficient demolding process. At the same time, the hemispherical elastic element provided in the present invention is also beneficial to ensuring the quality of the sand mold. The hemispherical cavity formed by the elastic element in the center of the sand mold shaft hole cavity, the hemispherical structure design optimizes the thickness distribution of the hollow sand mold on the inner wall of the shaft hole cavity, effectively avoiding the collapse, cracking and other defects caused by the thin inner wall of the shaft hole cavity sand mold, providing a stable and reliable cavity environment for casting molding, and ensuring the molding quality of the casting from the source.

[0016] 2. The present invention has a reasonable design and is less destructive to the mold. It does not require major improvements to the original mold or sand shooting equipment to solve the above problems and reduce the production costs of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a structural schematic diagram of the first mold of the present invention.

[0018] Figure 2 yes Figure 1 main view.

[0019] Figure 3 yes Figure 2 A magnified view of the local structure.

[0020] Figure 4 yes Figure 1 side view.

[0021] Figure 5 It is a structural schematic diagram of the second mold of the present invention.

[0022] Figure 6 yes Figure 5 main view.

[0023] Figure 7 yes Figure 5 side view.

[0024] Description of reference numerals: 1 - first mold, 11 - first base plate, 12 - first metal mold, 13 - first pouring cup, 14 - runner system, 141 - horizontal runner, 142 - vertical runner, 15 - elastic element, 2 - second mold, 21 - second base plate, 22 - second pouring cup, 23 - second metal mold, 24 - riser. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of implementation of the present invention is not limited thereto.

[0026] It should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0028] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 As shown, a vertical split sand mold for shaft hole castings of this embodiment includes a first mold 1 and a second mold 2 that cooperate with each other. The first mold 1 includes a first base plate 11, and a plurality of first metal molds 12, a first pouring cup 13 and a runner system 14 are provided on the upper surface of the first base plate 11. The first pouring cup 13 is located above the runner system 14, and the runner system 14 includes a horizontal runner 141 and a vertical runner 142. The vertical runner 142 is vertically arranged. The first metal molds 12 are arranged in an array, and two adjacent first metal molds 12 are symmetrically arranged so that the molten metal forms a symmetrical flow path in each row of cavities to avoid local pressure differences caused by uneven distribution. The axis of the axial hole of the first metal mold 12 is perpendicular to the first base plate 11. An elastic element 15 is provided inside the axial hole of the first metal mold 12. The elastic element 15 is hemispherical, and the center of the elastic element 15 is located on the axis of the axial hole of the first metal mold 12, ensuring that the elastic element 15 is located at the center of the axial hole of the first metal mold 12, so that the rebound force of the elastic element 15 can act evenly on the sand mold, ensuring the uniformity of the force on the sand mold inside the axial hole; The second mold 2 is provided with a second base plate 21, and a second pouring cup 22 and a second metal mold 23 are provided on the upper surface of the second base plate 21. The second pouring cup 22 is arranged corresponding to the first pouring cup 13. The first pouring cup 13 is used to form half of the cavity of the pouring cup in the sand mold, and the second pouring cup 22 is used to form the other half of the cavity of the pouring cup in the sand mold. After the two halves of the cavity are combined, the complete cavity of the pouring cup is obtained, and the molten metal is poured into the sand mold through the pouring cup; the second metal mold 23 is arranged corresponding to the first metal mold 12. The first metal mold 12 is used to form half of the cavity of the casting in the sand mold, and the second metal mold 23 is used to form the other half of the cavity of the casting in the sand mold. After the two halves of the sand mold are combined, a sand mold with a complete cavity of the casting is obtained, and a riser 24 is provided between two adjacent second metal molds 23. The riser 24 is arranged corresponding to the longitudinal runner 142 of the runner system 14.

[0029] In the present invention, the first mold 1 is a passive mold. When preparing the sand mold, the elastic element 15 is compressed by force. When the sand mold is demolded and separated from the first mold 1, the elastic element 15 plays a key role in the separation of the sand mold, especially the sand mold at the axial hole, from the first mold 1. During demolding, under the action of the elastic element 15's own rebound force, the elastic element 15 generates a certain thrust on the sand mold, which helps to demold and separate the sand mold from the first mold 1 and reduce the demolding resistance of the sand mold of the first metal mold 12 from the first mold 1. In the present invention, the elastic element is spherical or spherical cap. This structure has good geometric symmetry, which is conducive to uniform force on the sand mold of the axial hole during demolding, greatly improving the demolding performance of the sand mold and the inner wall of the axial hole of the first metal mold, ensuring the quality of the sand mold, and thus ensuring the quality of the casting.

[0030] The distance between the outer wall of the elastic element 15 and the inner wall of the shaft hole of the first metal mold 12 is not less than 5 mm, so as to avoid the sand mold of the inner wall of the shaft hole of the sand mold being too thin, resulting in the sand mold strength of the inner wall of the shaft hole being too low, and causing the sand mold to collapse after pouring metal.

[0031] The elastic element 15 is made of high-temperature resistant silicone, such as methyl vinyl silicone, phenyl vinyl silicone, fluorosilicone, borosilicate rubber, etc. The Shore hardness of the elastic element 15 is 60-90 Shore A, and the molecular chain cross-linking density is high, which makes the elastic element 15 more stable at higher temperatures; at the same time, when the sand mold is separated from the first mold 1, the elastic element 15 has a high resilience, which effectively reduces the demolding resistance between the sand mold and the first mold 1. The spherical cap height of the elastic element 15 is 0.5-1.1 times the radius of the ball. Preferably, the spherical cap height is 0.9-1.1 times the radius of the ball. In the case of being conducive to the demolding of the sand mold and the spherical cap, the larger the spherical cap height, the larger the volume of the elastic element 15 that can be compressed, the greater the resilience generated, and it is more conducive to reducing the demolding resistance between the sand mold and the axial hole of the first metal mold 12. It is further preferred that the spherical cap height is equal to the ball radius.

[0032] The surface of the elastic element 15 is provided with a concave-convex texture, which can be wavy, grid-shaped or a protruding dot matrix. The concave-convex texture can destroy the continuity between the contact surface between the sand mold and the elastic element 15, reduce the surface adhesion between the sand mold and the elastic element 15, facilitate the separation of the elastic element 15 from the sand mold, and reduce the demolding resistance.

[0033] The bottom of the axial hole of the first metal mold 12 is provided with an arc-shaped groove. The radius of the arc-shaped groove is 0.5-1mm larger than the radius of the elastic element 15. The elastic element covers the arc-shaped groove, forming a cavity at the bottom of the elastic element. The cavity is provided with air holes or is not sealed with the elastic element. When the sand mold is prepared by sand shooting, the arc-shaped groove provides elastic deformation space for the elastic element 15 to shrink and deform. When the sand mold is separated from the first mold 1, the elastic element 15 can generate a large rebound thrust, which helps significantly reduce the resistance to demolding.

[0034] The top surface height of the riser 24 is lower than the center height of the axial hole of the second metal mold 23. The top surface height of the riser 24 refers to the position of the upper end surface of the riser 24 in the vertical direction, and the center height of the axial hole of the second metal mold 23 refers to the position of the center of the axial hole of the second metal mold 23 in the vertical direction; the top surface height of the riser 24 is lower than the center height position of the axial hole of the second metal mold 23, so that the molten metal preferentially fills the axial hole during the pouring process. The riser 24 serves as a subsequent shrinkage feeding channel, which improves the shrinkage feeding efficiency of the riser 24, reduces casting defects of castings such as shrinkage cavities, and is conducive to ensuring the quality of castings.

[0035] The riser 24 is located outside the arc of the second metal mold 23, and the inner gate of the cavity is located outside the arc, and the sub-gate of the riser 24 is located below the axial hole, which is conducive to the flow of molten metal into the cavity, improves the shrinkage compensation efficiency of the riser 24, and reduces the air holes, inclusions, and shrinkage holes in the casting.

[0036] The thickness of the longitudinal runner 142 is 0.8-1.1 times the thickness of the first metal mold 12, which is beneficial to improving the shrinkage compensation efficiency of the casting and ensuring the fluidity of the molten metal. At the same time, it can also avoid the risk of deformation under the impact of high-temperature molten metal caused by the runner being too thin, and prevent the runner system 14 from having redundant volume caused by the runner being too thick.

[0037] At least two rows of second metal molds 23 arranged in the transverse direction are provided on the second base plate 21, and the number of second metal molds 23 in each row is at least two and is evenly spaced along the longitudinal direction, which is beneficial to improving the production efficiency of castings and reducing the variability of castings; the longitudinal runner 142 is a complete straight tube structure running through all rows of second metal molds 23, and the center line of the longitudinal runner 142 is perpendicular to the arrangement direction of each row of second metal molds 23, and the risers 24 between each row of second metal molds 23 are directly connected to the longitudinal runner 142; the cross-section of the longitudinal runner 142 is square, and the longitudinal runner 142 is provided with a draft angle of 1-3°. Through the cooperation of the complete straight tube runner and multiple rows of metal molds, the structure of the casting system is optimized, which is beneficial to achieving uniform flow of molten metal. At the same time, multiple rows of risers 24 are directly connected to the longitudinal runner 142 to form a straight shrinkage compensation channel, which can improve the shrinkage compensation efficiency of the molten metal and reduce problems such as shrinkage holes in castings.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A vertical parting sand casting mold for shaft hole castings, characterized by: It comprises a first mold (1) and a second mold (2) that match each other, The first mold (1) includes a first base plate (11), and the upper surface of the first base plate (11) is provided with a plurality of first metal molds (12), a first pouring cup (13) and a runner system (14), the first pouring cup (13) is located above the runner system (14), and the runner system (14) includes a horizontal runner (141) and a vertical runner (142), the first metal molds (12) are arranged in an array, and two adjacent first metal molds (12) are symmetrically arranged, and the axis of the axial hole of the first metal mold (12) is aligned with the axis of the first base plate ( 11) vertically arranged, an elastic element (15) is arranged inside the shaft hole of the first metal mold (12), the elastic element (15) is spherical or spherical, and the center of the elastic element (15) is located on the axis of the shaft hole of the first metal mold (12); the elastic element (15) is made of a high-resilience, high-temperature resistant silicone material; the surface of the elastic element (15) is provided with a concave-convex texture; an arc-shaped groove is provided at the bottom of the shaft hole of the first metal mold (12), and the radius of the arc-shaped groove is 0.5-1 mm larger than the radius of the elastic element (15); The second mold (2) is provided with a second base plate (21), and the upper surface of the second base plate (21) is provided with a second pouring cup (22) and a second metal mold (23), the second pouring cup (22) is provided corresponding to the first pouring cup (13), the second metal mold (23) is provided corresponding to the first metal mold (12), and a riser (24) is provided between two adjacent second metal molds (23), and the riser (24) is provided corresponding to the longitudinal runner (142) of the runner system (14).

2. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The distance between the outer wall of the elastic element (15) and the inner wall of the shaft hole of the first metal mold (12) is not less than 5 mm.

3. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The spherical cap height of the elastic element (15) is 0.5-1.1 times the spherical radius.

4. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The elastic element (15) has a Shore A hardness of 60-90 Shore A.

5. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The top surface height of the riser (24) is lower than the center height of the axial hole of the second metal mold (23).

6. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The riser (24) is located outside the arc of the second metal mold (23), and the gate of the riser (24) is located below the shaft hole.

7. The vertically split sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: The thickness of the longitudinal runner (142) is 0.8-1.1 times the thickness of the axial hole of the first metal mold (12), and the thickness of the riser (24) is 0.8-1.1 times the thickness of the second metal mold (23).

8. The vertically parted sand mold for casting of shaft-hole type castings according to claim 1, characterized in that: At least two rows of second metal molds (23) arranged in the transverse direction are provided on the second base plate (21), and the number of the second metal molds (23) in each row is at least two and is evenly spaced in the longitudinal direction; the longitudinal runner (142) is a complete straight tube structure that passes through all rows of second metal molds (23), the center line of the longitudinal runner (142) is perpendicular to the arrangement direction of each row of second metal molds (23), and the risers (24) between each row of second metal molds (23) are directly connected to the longitudinal runner (142); the cross section of the longitudinal runner (142) is square, and the longitudinal runner (142) is provided with a draft angle of 1-3°.

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