Rotor casting sand core and its gating system

Abstract

The utility model discloses a rotor casting sand core and pouring system, rotor casting sand core includes: bottom plate sand core, internal forming sand core and shell sand core, internal forming sand core includes the layered stack assembly of being equipped with bottom plate sand core to form the runner sand core of intermediate runner, the both sides of shell sand core are equipped with side riser, and side riser is communicated with casting cavity through riser neck, and side riser is equipped with heat preservation riser sleeve on, and the sidewall of shell sand core is preset with the positioning runner on bottom plate sand core bottom surface, and the pouring system includes straight pouring stick, main cross runner, sand core cross runner and bottom runner, and straight pouring stick is communicated with main cross runner beginning, and the main stream part of main cross runner is communicated bottom runner through sand core cross runner. Through above -mentioned mode, the utility model discloses through the bottom injection formula injection to make the molten iron along the runner direction steady into the cavity, through multistage purification filtration, three -dimensional exhaust and coordination, effectively avoid runner scouring and sand eye, ensure casting runner complete, promote casting quality.

Description

Technical Field

[0001] This utility model relates to the field of rotor casting technology, and in particular to a rotor casting sand core and its casting system. Background Technology

[0002] In recent years, with the technological advancements in various industries such as construction machinery and hydraulic equipment, the quality requirements for basic castings have become increasingly stringent. Rotor castings are key components in excavator hydraulic systems, containing complex hydraulic oil flow channels. To ensure the reliability and lifespan of excavators under harsh working conditions, these castings must possess excellent tensile strength, yield strength, and hardness, while also ensuring the integrity and unobstructed flow of internal channels. Any defects can lead to hydraulic system failure.

[0003] Currently, this type of casting is generally produced using the traditional casting method of horizontal placement and feeding through risers placed on the side. Molten iron is poured in from the bottom and fills the cavity from bottom to top, which has the following defects: Due to the complex structure of the casting, there are many flow channels inside. When the high-temperature molten iron encounters obstacles in the flow channels, the flow direction and speed change, forming an impact, which causes the sand core to shift or erode, ultimately causing the flow channels to deform. In addition, the direct impact of molten iron on the relatively fragile flow channel sand core can easily cause the sand core to break. The broken sand core fragments will flow with the molten iron or remain in the mold cavity, thus causing blockage of the casting flow channel.

[0004] When such defective rotor castings are assembled onto an excavator, the blocked or deformed flow channels will cause poor oil flow or abnormal system pressure when hydraulic oil is introduced, rendering the entire excavator unusable. Utility Model Content

[0005] The main technical problem solved by this utility model is to provide a rotor casting sand core and its pouring system. The system allows molten iron to enter the mold cavity smoothly along the flow channel through bottom pouring. Through multi-stage purification and filtration, three-dimensional venting and coordinated feeding, it can effectively avoid flow channel erosion and sand holes, ensuring the integrity of the casting flow channel, internal cleanliness and dense structure, thus improving the quality of the casting.

[0006] To solve the above-mentioned technical problems, the present invention adopts a technical solution as follows: providing a rotor casting sand core, including a bottom plate sand core, an internal forming sand core, an outer shell sand core, a side riser and an insulating riser sleeve, wherein a casting cavity is formed between the internal forming sand core and the outer shell sand core, and the internal forming sand core includes at least one layer of flow channel sand core disposed on the bottom plate sand core, wherein the flow channel sand core is stacked in layers to form an intermediate flow channel; The outer shell sand core includes a left outer shell sand core and a right outer shell sand core located outside the inner forming sand core. The outer shell sand core has side risers on both sides for feeding. The side risers are connected to the casting cavity through riser necks. The side risers are provided with heat-insulating riser sleeves. The outer shell sand core sidewall to the bottom surface of the bottom plate sand core has a positioning gating channel.

[0007] In a preferred embodiment of this utility model, the left outer shell sand core and the right outer shell sand core are initially positioned by a concave-convex fit and are then fastened by a locking member; the outer shell sand core as a whole is initially positioned with the bottom plate sand core by a concave-convex fit and is then fastened by a locking member.

[0008] In a preferred embodiment of the present invention, the flow channel sand core includes a main body and an elongated flow channel extending downward along the side of the main body. The main body is frustum-shaped, with a positioning boss at the bottom and a positioning groove adapted to the positioning boss at the top.

[0009] In a preferred embodiment of this utility model, the flow channel sand cores of adjacent layers are positioned and assembled by the cooperation of positioning bosses and positioning grooves.

[0010] In a preferred embodiment of the present invention, each layer of the flow channel sand core is provided with a connected vent hole, forming an internal venting channel that runs through the entire internal molded sand core.

[0011] In a preferred embodiment of the present invention, the top of the outer shell sand core is provided with an exhaust needle communicating with the internal exhaust channel, and the top of the thermal insulation riser sleeve is provided with an overflow needle.

[0012] In a preferred embodiment of this utility model, a chilled iron assembly is also pre-embedded on the base plate sand core.

[0013] To solve the above-mentioned technical problems, another technical solution adopted by this utility model is: to provide a casting system, including the rotor casting sand core and a bottom-pouring casting mechanism, wherein the bottom-pouring casting mechanism includes a pouring rod, a main horizontal runner, a sand core horizontal runner, and a bottom runner, the pouring rod being connected to the beginning of the main horizontal runner, and a first slag collection groove being provided at the end of the main horizontal runner. The main stream of the main horizontal pouring channel is connected to the bottom pouring channel through the sand core horizontal pouring channel. The bottom pouring channel is provided with a second slag collection trough at its end, and a filter block is provided on the pouring path of the bottom pouring channel.

[0014] In a preferred embodiment of this utility model, the positioning gating channel is adapted to the sand core horizontal gating channel and the bottom gating channel, and the depth of the positioning gating channel is 0.5~2mm.

[0015] In a preferred embodiment of this utility model, the filter block is partially pressed into the bottom plate sand core, with a pressing depth of 3~8mm.

[0016] The beneficial effects of this utility model are: Bottom-pouring ensures the molten iron fills the mold smoothly along the flow path, completely avoiding frontal erosion of the fragile sand core and guaranteeing the integrity of the flow path. The molten iron undergoes multi-stage slag collection, buffering, and filtration for layer-by-layer purification, significantly improving internal cleanliness. A three-dimensional venting network effectively removes gas from the mold cavity and sand core, preventing porosity and sand hole defects. Bottom chills and side insulating risers work together to control the solidification sequence, forming bottom-up directional solidification, greatly enhancing the feeding effect, ensuring the overall density of the casting, and guaranteeing casting quality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein: Figure 1 This is a schematic diagram of a preferred embodiment of the rotor casting sand core and its casting system of this utility model; Figure 2 This is a schematic diagram of a preferred embodiment of the positioning gating system on the sand core of the rotor casting of this utility model; Figure 3 This is a schematic diagram of a preferred embodiment of the riser and chill assembly on the sand core of the rotor casting of this utility model; Figure 4 This is a schematic diagram of a preferred embodiment of the exhaust overflow structure on the sand core of the rotor casting of this utility model; Figure 5 This is a schematic diagram of a preferred embodiment of the internally formed sand core of this utility model; Figure 6 This is a schematic diagram of a preferred embodiment of the flow channel sand core of this utility model; The components in the attached diagram are labeled as follows: 1. Base plate sand core; 11. Chilled iron assembly; 12. Positioning gating; 2. Internal forming sand core; 21. Flow channel sand core; 211. Main body; 212. Flow channel; 213. Positioning boss; 214. Positioning groove; 3. Outer shell sand core; 31. Left outer shell sand core; 32. Right outer shell sand core; 33. Venting pin; 4. Side riser; 5. Insulating riser sleeve; 51. Overflow pin; 6. Straight pouring rod; 7. Main horizontal gating; 71. First slag collection trough; 8. Sand core horizontal gating; 9. Bottom gating; 91. Second slag collection trough; 92. Filter block. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] Please see Figures 1 to 6 This embodiment provides a rotor casting sand core, which mainly includes: a base plate sand core 1, an internal forming sand core 2, an outer shell sand core 3, a side riser 4, and an insulating riser sleeve 5.

[0021] The internal molding sand core 2 and the outer shell sand core 1 form a casting cavity. The internal molding sand core 2 is assembled by stacking at least one layer of flow channel sand cores 21 on the bottom sand core 1 to form the intermediate flow channel required for the casting. In this embodiment, it is preferable to use four layers of flow channel sand cores 21 for assembly.

[0022] In detail, the flow channel sand core 21 includes a main body 211 and an elongated flow channel 212 extending downward along the side of the main body 211. The main body 211 is frustum-shaped, and a positioning boss 213 is provided at the bottom of the main body 211. A positioning groove 214 adapted to the positioning boss 213 is provided at the top of the main body 211.

[0023] The flow channel sand cores 21 of adjacent layers are positioned and assembled quickly and accurately through the precise cooperation between the positioning boss 213 of the upper sand core and the positioning groove 214 of the lower sand core.

[0024] Furthermore, each layer of the flow channel sand core 21 is provided with interconnected vent holes. These vertically connected vent holes constitute an internal venting channel that runs through the entire internal molded sand core, used to exhaust the gas generated by the sand core after being heated during casting.

[0025] The outer shell sand core 3 includes a left outer shell sand core 31 and a right outer shell sand core 32, which are assembled together and placed outside the inner molded sand core 2.

[0026] The left outer shell sand core 31 and the right outer shell sand core 32 are initially positioned by a convex-concave fit and then secured by locking components (e.g., screws). Similarly, the outer shell sand core 3 as a whole is initially positioned to the base plate sand core 1 by a convex-concave fit and then secured by locking components. In this embodiment, a total of 8 screws are used for overall securing.

[0027] The outer shell sand core 3 has side risers 4 on both sides for feeding. The side risers 4 are connected to the casting cavity through riser necks, and heat-insulating riser sleeves 5 are provided on the side risers 4 to delay the solidification time of the molten iron in the risers. In order to assist venting and overflow, an venting needle 33 connected to the internal venting channel is provided at the top of the outer shell sand core 3, and an overflow needle 51 is provided at the top of the heat-insulating riser sleeve 5.

[0028] On the bottom sand core 1, a pre-embedded chill assembly 11 is used to accelerate the cooling and solidification of the bottom of the casting and increase the riser feeding distance.

[0029] The two side risers 4 mentioned above are equipped with heat-insulating riser sleeves 5, which keep the molten iron in the riser warm, increase the riser feeding, and, together with the bottom chill group 11, accelerate solidification. The bottom chill causes solidification from bottom to top, which, combined with the side risers providing feeding from top to bottom, increases the effective feeding distance of the riser.

[0030] Furthermore, a positioning gating channel 12 with a depth of 0.5~2mm is pre-set on the side wall of the outer shell sand core 3 to the bottom surface of the bottom plate sand core 1. In this embodiment, the depth of the positioning gating channel 12 is pre-set to 1mm.

[0031] The shallow groove-shaped positioning runner 12 has the following main functions: First, it can accurately locate the position of the gating system during subsequent box assembly, providing a precise reference for the positioning of the gating system; second, it serves as an assembly gap to prevent sand particles from entering the cavity and causing sand hole defects due to friction between the sand core and the outer mold during hoisting and box assembly; third, it facilitates the application of coating in this area to prevent the gating system from directly scouring the sand core and avoiding the formation of sand holes.

[0032] Furthermore, the corner portion of the bottom plate sand core 1 adopts a conformal structure, that is, the shape matches the contour of the corresponding part of the casting. While ensuring the strength of the sand core, the volume and weight of the sand core are reduced to the maximum extent, thereby achieving the purpose of saving molding materials and reducing production costs.

[0033] Based on the above structure, this utility model also provides a matching casting system, including the rotor casting sand core and a bottom-pouring casting mechanism, which includes a straight pouring bar 6, a main horizontal runner 7, a sand core horizontal runner 8 and a bottom runner 9.

[0034] The direct pouring rod 6 is connected to the beginning of the main horizontal pouring channel 7. The end of the main horizontal pouring channel 7 is provided with a first slag collection trough 71. The main stream of the main horizontal pouring channel 7 is connected to the bottom pouring channel 9 through the sand core horizontal pouring channel 8. The end of the bottom pouring channel 9 is provided with a second slag collection trough 91, and a filter block 92 is provided on the pouring path of the bottom pouring channel 9.

[0035] The filter block 92 is partially pressed into the bottom sand core 1 to a depth of 3-8 mm. The filter block is placed directly at the ingate, serving as the best retainer for the gating system and effectively preventing sand and slag holes generated by the entire gating system from clogging the outside of the casting.

[0036] The casting corresponding to this invention has four narrow runners. If conventional casting processes are used, with the casting placed horizontally, the molten iron will directly impact the runners, causing damage. The bottom gating arrangement of this invention ensures that after the molten metal is injected from the bottom of the casting cavity, its filling direction is consistent with the extension direction of the narrow runners inside the casting, avoiding direct impact on the runners and effectively guaranteeing the quality of the casting.

[0037] The working process of the casting system of this utility model is as follows: Molten iron first enters the beginning of the main horizontal runner 7 from the straight pouring bar 6. The first molten iron with low temperature and high slag content is transported to the first slag collection tank 71 at the end of the main horizontal runner 7 to achieve primary slag collection. Subsequently, the pre-purified molten iron enters the sand core horizontal pouring channel 8 set on the sand core. This stream of molten iron will first rush into a buffer bag 81. The buffer bag 81 effectively consumes the kinetic energy of the molten iron by changing the direction and cross-sectional area of ​​the flow channel, thereby reducing its flow rate and making the flow more stable. After being buffered and slowed down, the molten iron returns and flows into the bottom gating 9 at the very bottom of the mold cavity.

[0038] In this embodiment, the molten iron needs to be purified before entering the mold cavity: First, a second slag collection trough 91 is provided at the end of the bottom gating channel 9 for the final collection of floating slag; then, the molten iron will flow through the filter block 92 set on the pouring path, which serves as the final barrier to filter out fine suspended impurities.

[0039] In this embodiment, the filter block 92 is partially pressed into the bottom plate sand core 1 to a depth of 5mm, which can effectively prevent molten iron from flowing through the assembly gap between the filter block and the sand core, causing impurities to enter the cavity directly without being filtered.

[0040] Finally, the clean molten iron is injected from the bottom of the mold cavity at a low speed and rises steadily along the direction of the casting flow channel. This bottom-pouring filling method completely avoids the direct impact on the four small flow channels, fundamentally solving the problem of easy damage to the flow channel sand core.

[0041] The beneficial effects of this utility model of rotor casting sand core and its casting system are: The bottom-pouring method allows molten iron to enter the mold cavity along the flow channel direction. The flow direction is consistent with the extension direction of the four slender flow channels inside the casting, avoiding the front scouring of the flow channel sand core and effectively ensuring the quality of the casting. The molten iron undergoes primary purification through the slag collection trough at the end of the main horizontal runner, secondary purification through the buffer ladle in the sand core horizontal runner, and final filtration through the slag collection trough at the end of the bottom runner. This multi-layer purification and stable filling process significantly improves the cleanliness of the castings. The three-dimensional venting network from the inside out ensures that the gas can be discharged smoothly during the pouring process, preventing defects such as pores and sand holes caused by gas retention. By pre-embedding chills at the bottom and using side-insulating risers to control the solidification sequence of castings, the effective feeding distance of the risers is increased, thus solving the shrinkage porosity problem.

[0042] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A rotor casting sand core, characterized in that, include: Base plate sand core, internal molded sand core, outer shell sand core, side risers and insulating riser sleeves, A casting cavity is formed between the internal forming sand core and the outer shell sand core. The internal forming sand core includes at least one layer of flow channel sand core disposed on the bottom plate sand core. The flow channel sand cores are stacked and assembled in layers to form an intermediate flow channel. The outer shell sand core includes a left outer shell sand core and a right outer shell sand core located outside the inner forming sand core. The outer shell sand core has side risers on both sides for feeding. The side risers are connected to the casting cavity through riser necks. The side risers are provided with heat-insulating riser sleeves. The outer shell sand core sidewall to the bottom surface of the bottom plate sand core is pre-set with positioning pouring channels.

2. The rotor casting sand core according to claim 1, characterized in that, The left and right outer shell sand cores are initially positioned by a convex-concave fit and are then secured by a locking mechanism; the outer shell sand core as a whole is initially positioned by a convex-concave fit and is then secured by a locking mechanism.

3. The rotor casting sand core according to claim 1, characterized in that, The flow channel sand core includes a main body and a slender flow channel extending downward along the side of the main body. The main body is frustum-shaped, with a positioning boss at the bottom and a positioning groove at the top that matches the positioning boss.

4. The rotor casting sand core according to claim 3, characterized in that, The flow channel sand cores of adjacent layers are positioned and assembled by the cooperation of positioning bosses and positioning grooves.

5. The rotor casting sand core according to claim 1, characterized in that, Each layer of the flow channel sand core is provided with interconnected vent holes, forming an internal venting channel that runs through the entire internal molded sand core.

6. The rotor casting sand core according to claim 5, characterized in that, The top of the outer shell sand core is provided with an exhaust needle that communicates with the internal exhaust channel, and the top of the thermal insulation riser is provided with an overflow needle.

7. The rotor casting sand core according to claim 1, characterized in that, The base plate sand core also has pre-embedded chilled iron blocks.

8. A casting system, characterized in that, include: The rotor casting sand core and a bottom-pouring casting mechanism as described in any one of claims 1-7, wherein the bottom-pouring casting mechanism includes a pouring bar, a main horizontal runner, a sand core horizontal runner, and a bottom runner, the pouring bar being connected to the beginning of the main horizontal runner, and a first slag collection groove being provided at the end of the main horizontal runner. The main stream of the main horizontal pouring channel is connected to the bottom pouring channel through the sand core horizontal pouring channel. The bottom pouring channel is provided with a second slag collection trough at its end, and a filter block is provided on the pouring path of the bottom pouring channel.

9. The gating system according to claim 8, characterized in that, The positioning gating channel is adapted to the sand core horizontal gating channel and the bottom gating channel, and the depth of the positioning gating channel is 0.5~2mm.

10. The gating system according to claim 8, characterized in that, The filter block is partially pressed into the bottom plate sand core to a depth of 3-8mm.

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