Composite casting mold casting process device for screw rod casting of screw rod compressor rotor
By adopting a composite casting process device in the production of rotor screw castings by screw compressor, combining iron sand-covered casting and shell casting technology, the problems of low quality, low efficiency and high cost of rotor screw castings in the existing technology are solved, and high-quality and low-cost mass production is achieved.
Patent Information
- Application Number
- CN202421605554.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-09
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-07-09
AI Technical Summary
The existing rotor screw casting production process has problems such as low quality, low efficiency, high scrap rate and high production costs, which is difficult to meet the needs of improving the quality of screw compressor products and large-scale production.
The composite casting process device of screw compressor rotor screw castings is adopted, including upper iron type, lower iron type, casting system and iron type locking device. Through iron sand-covered casting and shell type casting technology, composite casting molds of the spiral tooth surface of the rotor screw are formed, realizing axial vertical arrangement and intermediate partitioning.
The surface roughness, dimensional accuracy and comprehensive mechanical properties of rotor screw castings are improved, production costs are reduced, and large-scale mechanized production of rotor screw castings is realized.
Smart Images
Figure CN222873310U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a process device, in particular to a composite mold casting process device for a screw compressor rotor screw casting, and belongs to the field of iron mold sand-coated casting and shell mold casting technology. Background Art
[0002] The screw compressor is a high-efficiency, energy-saving, low-noise gas compression and refrigeration device with the characteristics of simple structure, few wearing parts, low exhaust temperature and large pressure ratio. Its application areas and application volume are becoming increasingly wide.
[0003] The J screw compressor uses two rotors with helical gears (hereinafter referred to as: rotor screw) (see Figure 1-Figure 3 ) mesh with each other to compress the gas. The production of rotor screw castings is currently still mainly sand casting (green sand or self-hardening resin sand), and the spiral gear surface casting cavity in the rotor screw is made by manual rotation. The quality and production efficiency of the rotor screw are relatively low, the scrap rate is high, and the production cost is high. With the improvement of the quality of screw compressor products and the continuous increase in demand, the existing rotor screw production process and production form have become the bottleneck of the development of screw compressors.
[0004] Iron mold sand-coated casting technology is an energy-saving, efficient, high-quality and green casting production technology. According to the structural characteristics and process requirements of rotor screw castings, the multiple advantages of iron mold sand-coated casting technology are utilized, combined with shell mold casting to form the rotor screw spiral tooth surface, forming an iron mold sand-coated and shell mold composite casting, which is used in the casting production of compressor rotor screw castings to achieve high-quality, high-yield and mechanized mass production of rotor screw castings. Utility Model Content
[0005] The purpose of the utility model is to overcome the above-mentioned deficiencies in the prior art and to provide a composite casting mold casting process device for screw compressor rotor screw castings which has a reasonable structural design, is safe and reliable, has low production cost, has good surface roughness of the produced rotor screw, has high dimensional accuracy, and has good comprehensive mechanical properties, thereby improving the production efficiency of rotor screw castings and realizing large-scale mechanized production of rotor screw castings.
[0006] The technical solution adopted by the utility model to solve the above-mentioned problem is: a composite casting process device for the screw compressor rotor screw casting comprises an upper iron mold, a lower iron mold, a pouring system and an iron mold locking device, wherein the upper iron mold and the lower iron mold are fixed by the iron mold locking device, and is characterized in that: it also comprises an iron mold covered with sand casting mold and a coated sand shell mold with a backing iron mold covered with sand cavity, the rotor screw casting is axially arranged vertically in the iron mold and parted in the middle; the support shaft casting cavity at both ends of the rotor screw is formed by an iron mold covered with sand casting mold, and the screw spiral tooth surface casting cavity of the rotor screw is formed by a coated sand shell mold with a backing iron mold covered with sand.
[0007] Preferably, the pouring system of the utility model is in the form of a multi-branched center-injection water injection, and the pouring system includes a straight runner, a forked cross runner and an inner runner.
[0008] Preferably, the sand coating thickness of the iron mold sand-coated casting mold cavity of the utility model is 6-9 mm, the sand coating thickness of the backing iron mold sand-coated mold cavity for placing the coated sand shell mold is 3-4 mm, and the sand coating thickness of the pouring system is 10-15 mm.
[0009] Preferably, the outer conical surface of the shell type of the screw helical tooth surface of the utility model has a draft angle of 0.8°-1° at the lower part of the parting surface, and a draft angle of 4°-5° at the upper part of the parting surface.
[0010] Preferably, the shell thickness of the thinnest part of the shell of the helical tooth surface of the screw in the utility model is 7-10 mm.
[0011] Compared with the prior art, the utility model has the following advantages and effects: 1) The overall structural design is reasonable, safe and reliable. The rapid cooling conditions of the iron mold sand-coated casting are utilized to greatly refine the grain structure and metallographic structure morphology of the rotor screw casting, which is beneficial to improving the comprehensive mechanical properties of the rotor screw casting; 2) Through the high rigidity of the iron mold sand-coated casting, the graphitization expansion of ductile iron during the solidification process can be utilized to make the internal structure of the rotor screw casting more compact, and the riser-free casting of the rotor screw casting can be realized, thereby improving the process yield of the rotor screw casting production; 3) The iron mold sand-coated casting cavity of the two-end support shaft part of the rotor screw, the spiral tooth surface shell cavity of the rotor screw, etc. are all formed by sand shooting and sand coating, and the cavity surface The surface is tight and dense, and no coating is required. The produced rotor screw has good surface roughness, high dimensional accuracy, and good consistency in the surface and size of the rotor screw, which can greatly reduce the machining allowance of the rotor screw and reduce the processing cost; 4) The rotor screw composite casting adopts a vertical arrangement to ensure that the axial dynamic balance performance requirements of the rotor screw casting are met; 5) The iron mold coated with sand in the utility model can arrange multiple rotor screws in one mold according to the size of the rotor screw, which greatly improves the production efficiency of the rotor screw casting; 6) The iron mold coated with sand casting-shell mold casting technology is used for the production of rotor screw castings. Combined with the iron mold coated with sand casting production line, the mechanized, automated, and intelligent production of rotor screw castings can be realized. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 It is a schematic diagram of the axonometric structure of the rotor screw casting in the embodiment of the utility model.
[0013] Figure 2 It is a schematic diagram of the main structure of the rotor screw casting in the embodiment of the utility model.
[0014] Figure 3 It is a schematic diagram of the top view of the rotor screw casting in the embodiment of the utility model.
[0015] Figure 4 It is a schematic diagram of the front view of the composite casting device of the embodiment of the utility model.
[0016] Figure 5 It is a schematic top view of a combined casting mold device according to an embodiment of the utility model.
[0017] Figure 6 It is a schematic diagram of the main structure of the upper iron mold of the iron mold covered with sand casting in the composite casting device of the embodiment of the utility model.
[0018] Figure 7 The utility model is a schematic diagram of the top structure of the upper iron mold of the iron mold covered with sand casting in the composite casting device of the embodiment of the utility model.
[0019] Figure 8It is a schematic diagram of the main structure of the lower iron mold of the iron mold covered with sand casting in the composite casting device of the embodiment of the utility model.
[0020] Fig. 9 It is a schematic diagram of the top view of the structure of the lower iron mold of the iron mold covered with sand casting in the composite casting device of the embodiment of the utility model.
[0021] Fig.10 This is a schematic diagram of the shell structure of the helical gear surface in the composite casting device of the utility model embodiment Figure 1 .
[0022] Fig.11 The shell structure of the helical gear surface in the composite casting device of the embodiment of the present invention is shown in FIG. Figure 2 .
[0023] Fig.12 It is a schematic diagram of placing the screw spiral shell mold in the lower iron mold and preparing for assembling the mold during the production process of the rotor screw casting in the composite casting device of the embodiment of the utility model.
[0024] Fig.13 It is a schematic diagram of iron mold assembling and locking during the production process of rotor screw castings in the composite casting device of the embodiment of the utility model.
[0025] Fig.14 It is a schematic diagram of molten iron pouring and filling in the mold during the production process of the rotor screw casting in the composite casting device of the embodiment of the utility model.
[0026] Fig.15 It is a schematic diagram of solidification and cooling of molten iron after pouring and filling the mold in the production process of the rotor screw casting in the composite casting device of the embodiment of the utility model.
[0027] Fig.16 It is a schematic diagram of the casting after unpacking during the production process of the rotor screw casting in the composite casting device of the embodiment of the utility model.
[0028] Fig.17 It is a schematic diagram of the pouring system after unpacking during the production process of the rotor screw casting in the composite casting device of the embodiment of the utility model.
[0029] In the figure: upper iron mold 1, lower iron mold 2, screw spiral tooth surface 3, support shaft 4, shell mold 5, pouring system 6, straight runner 7, forked cross runner 8, ingendant 9, iron mold locking device 10, box buckle 11, backing iron mold sand-covered cavity 12, ingendant 13, pouring cup 14; the thickness of the sand coating layer H1 is 3-4 mm, the thickness of the sand coating layer H2 is 6-9 mm, the thickness of the sand coating layer H3 is 10-15 mm, the thickness of the shell mold H4 is 7-10 mm, the die draft angle X1 is 4°-5°, and the die draft angle X2 is 0.8°-1°. DETAILED DESCRIPTION
[0030] The present invention will be further described in detail below with reference to the accompanying drawings and through examples. The following examples are provided to explain the present invention, but the present invention is not limited to the following examples.
[0031] Example
[0032] See also Figures 1 to 17 The process principle of the composite mold casting process device of the screw compressor rotor screw casting of this embodiment is as follows: the working surface of the compressor rotor screw casting is a spiral tooth surface structure, and a screw compressor generally consists of two rotor screws (i.e., left and right rotor screws) whose spiral tooth surfaces are completely meshed with each other to form a gas compression chamber. The surface roughness and dimensional accuracy of the spiral tooth surface of the rotor screw are very high, and the dynamic balance requirements of the rotor screw during rotation are also very high (directly affecting the noise, vibration, life, and operating efficiency of the compressor during operation). The spiral tooth surface of the early rotor screw was formed by machining rods, and sand casting is gradually used to form the spiral tooth surface of the rotor screw. At present, the casting of the rotor screw is produced by green sand or self-hardening resin sand, and most of the rotor screws are arranged axially horizontally. The rotor screw castings produced by this casting method have the following deficiencies: (1) The rotor screw is produced in a horizontal arrangement, with half of the rotor screw circumferential cavity in the lower mold and the other half in the upper mold. After the molten iron is poured into the mold cavity, the graphite precipitated from the molten iron during the cooling and solidification process will have a specific gravity. After the final solidification, the specific gravity of the upper half of the rotor screw will be lighter than that of the lower half, which is not conducive to the dynamic balance of the rotor screw during rotation. (2) The size of the spiral tooth surface of the rotor screw is much larger than the size of the support shaft 4 at both ends of the rotor screw. The existing horizontal arrangement of sand casting makes it difficult to meet the requirements of the molten iron in the spiral tooth surface 3 of the rotor screw. Liquid shrinkage compensation requires that shrinkage cavities and shrinkage defects are easily generated inside the spiral tooth surface of the cast rotor screw; (3) The horizontal arrangement of the existing sand casting makes it easy for slag to accumulate on the spiral tooth surface 3 of the rotor screw in the upper mold, requiring a larger processing allowance, increasing the weight of the casting and processing time. At the same time, the axial horizontal arrangement of the rotor screw will cause a dynamic balance difference in the rotation of the rotor screw due to the different specific gravity of the upper and lower circular cross-sections during the solidification and cooling of the molten iron, causing the screw air compressor to produce certain vibrations in the working state, affecting the balanced operation, efficiency, and service life of the screw air compressor.
[0033] The casting process of the rotor screw in this embodiment is that the rotor screw is arranged vertically, the middle part of the spiral surface of the rotor screw is cast on the side, the support shaft 4 at both ends of the rotor screw is formed by iron mold sand coating, and the rotor screw spiral tooth surface 3 is formed by shell mold and axially vertically placed in the backing iron mold sand coating cavity 12 of the lower iron mold, and a complete composite casting structure is formed after the box is closed. The axial vertical arrangement of the rotor screw in the casting mold avoids the inconsistency of the density ratio of the rotor screw on the circumferential cross section caused by the cooling sequence of the molten iron after entering the casting mold, thereby ensuring the dynamic balance performance of the rotor screw from the process point of view.
[0034] The composite casting structure of this embodiment can make good use of the high rigidity and high cooling rate of the iron sand-coated casting mold, give full play to the graphitization expansion of ductile iron to offset the liquid shrinkage of molten iron, obtain a metallographic structure with dense internal structure, fine grains, and excellent graphite morphology, and at the same time greatly improve the utilization rate of molten iron in the production process of the casting, realize riser-free casting, further reduce the production cost of such castings, and obtain good production economic benefits.
[0035] like Figure 4-Figure 5 As shown, the composite mold casting process device for the screw compressor rotor screw casting of this embodiment includes an upper iron mold 1, a lower iron mold 2, a shell mold 5, a pouring system 6 and an iron mold locking device 10, and the upper iron mold 1 and the lower iron mold 2 are also connected with a box buckle 11.
[0036] The pouring system 6 in this embodiment includes a sprue 7 , a bifurcated runner 8 and an ingrate 9 , and an ingrate 13 is disposed in the ingrate 9 .
[0037] The composite casting process device of this embodiment is a screw casting axially arranged vertically, split in the middle, and using an upper and lower mold to form a casting mold. In the utility model application, according to the different plane sizes of the casting mold, a mold can be vertically arranged with multiple screw casting molds to form a complete casting mold.
[0038] The casting mold structure of the composite casting process device of this embodiment is a composite casting mold, which is mainly composed of two parts, namely: an iron mold covered with sand casting mold and a coated sand shell type backing iron mold covered with sand casting mold placed in the backing iron mold covered with sand cavity; wherein: the iron mold covered with sand casting mold mainly forms the casting cavities of the upper and lower support shafts 4 at the upper and lower ends of the rotor screw, and the shell type backing iron mold covered with sand casting mold of the spiral surface of the coated sand screw mainly forms the complete rotor spiral tooth surface casting cavity of the rotor screw (there is no parting surface on the spiral surface cavity of the rotor screw of the shell type, and there is no demolding slope. It is a single spiral surface complete cavity, which can greatly reduce the processing workload of the spiral surface).
[0039] like Figure 6-Figure 9As shown, the iron mold sand-coated casting mold is divided into an upper iron mold 1 and a lower iron mold 2, the rotor screw is arranged axially vertically in the iron mold, and the support shafts 4 at both ends of the rotor screw are arranged in the upper iron mold 1 and the lower iron mold 2 respectively, and the backing iron mold sand-coated cavity of the coated sand shell type for placing the screw spiral tooth surface 3 of the rotor screw is divided into two parts, one part is arranged in the lower iron mold 2, and the other part is arranged in the upper iron mold 1; the thickness H2 of the sand coating layer of the iron mold sand-coated casting mold is 6-9 mm, the thickness H1 of the sand coating layer of the backing iron mold sand-coated cavity 12 for placing the coated sand shell type is 3-4 mm, and the thickness H3 of the sand coating layer of the casting system 6 is 10-15 mm.
[0040] The screw spiral tooth surface 3 of the rotor screw is integrally coated with a sand shell structure, such as Figure 10-11 As shown, the shell mold 5 structure of the screw helical tooth surface 3 mainly forms a complete rotor screw shell mold helical tooth surface integral casting cavity, and the entire spiral gear surface has no draft angle and no parting surface. The casting cavity of the rotor screw helical tooth surface 3 is formed in the inner cavity of the shell mold, and the shell mold thickness H4 at the thinnest part of the shell mold 5 of the rotor helical tooth surface 3 is controlled to be 7-10 mm. The draft angle X2 of the outer conical surface of the shell mold 5 of the rotor screw helical tooth surface 3 at the lower part of the parting surface is 0.8°-1°, and the draft angle X1 at the upper part of the parting surface is 4°-5°. The outer shape of the shell mold 5 of the spiral tooth surface 3 of the rotor screw is basically consistent with the size of the backing iron mold sand-covered cavity 12 in the upper iron mold 1 and the lower iron mold 2 of the iron mold covered with sand, but there is a certain gap between the two, that is: there is a certain gap between the outer conical surface of the shell mold 5 of the spiral tooth surface 3 of the rotor screw and the conical surface of the backing iron mold sand-covered cavity 12, and the size of the gap between the two is controlled at 0.1-0.2 mm.
[0041] The pouring system 6 of the composite casting of the screw casting of this embodiment is in the form of a multi-branched center pouring type, that is, the molten iron passes through the straight runner 7, the bifurcated cross runner 8, and the inner runner 9 of each screw casting (see Figure 4-Figure 5 Each screw casting cavity has an ingrate 9, and the bottom surface of the water entry position of the ingrate 9 is on the lower plane of the parting surface of the upper iron mold 1 (see Figure 4-Figure 5 ), the inner runner 9 is formed partly on the iron mold covered with sand casting and partly on the shell mold 5 of the screw helical tooth surface 3 (see Figure 4-Figure 5 ), that is, the contact portion between the ingates 9 and the cavity of the screw helical tooth surface 3 is made directly in the shell mold 5 of the screw helical tooth surface 3 (see Figure 10-11 ), when the iron mold covered with sand casting is combined with the shell mold 5 of the screw spiral tooth surface 3, a complete ingates 9 channel cavity is formed.
[0042] The production process of the composite casting process device for the screw compressor rotor screw casting of this embodiment is as follows: Figure 12-Figure 17As shown, the specific steps are as follows; first, the upper iron mold 1 and the lower iron mold 2 of the rotor screw are respectively molded into the iron mold sand-coated casting mold, and the rotor screw spiral tooth surface 3 cavity shell mold is molded; the rotor screw spiral tooth surface 3 cavity shell molds are placed one by one into the lower iron mold 2 of the rotor screw; then the upper iron mold 1 and the lower iron mold 2 of the rotor screw are combined into a box and the upper iron mold 1 and the lower iron mold 2 are locked after the combination to form a composite mold of an iron mold covered with sand-shell mold for rotor screw casting production; then molten iron is poured into the mold cavity of the composite mold through a pouring cup 14 placed on the upper iron mold 1, and after the molten iron is completely filled, the molten iron in the iron mold sand-coated casting cavity and the shell mold casting cavity of the composite mold is cooled and solidified, and the upper iron mold 1 and the lower iron mold 2 are unpacked, and the casting in the composite mold is taken out to obtain a rotor screw casting, thereby completing a casting process of a rotor screw casting. The process is repeated one after another to form batch production of rotor screw castings.
[0043] According to the product structure requirements, production process requirements, and casting production process requirements of the screw compressor rotor screw casting, this embodiment combines the characteristics of the iron mold sand-coated casting production process and the shell mold casting process. The rotor screw casting adopts a vertical arrangement and horizontal parting. The screw casting adopts a composite casting mold formed by combining an iron mold sand-coated casting mold and a coated sand shell mold, that is, the cavity surfaces of the supporting shafts 4 at both ends of the rotor screw casting are formed by the iron mold sand-coated casting mold, and the cavity surface of the spiral gear face in the middle of the rotor screw is formed by the coated sand shell mold cavity; the above two casting boxes are assembled to form a complete rotor screw composite casting, and then molten iron is poured and filled into the mold. After the molten iron solidifies and cools, the rotor screw casting is finally produced, thereby realizing mass production of rotor screw castings.
[0044] Through the above description, those skilled in the art can already implement it.
[0045] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the utility model. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the utility model are included in the protection scope of the utility model patent. Technicians in the technical field of the utility model can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the utility model or exceed the scope defined by the claims, they should all fall within the protection scope of the utility model.
Claims
1. A composite mold casting process device for a screw compressor rotor screw casting, comprising an upper iron mold (1), a lower iron mold (2), a pouring system (6) and an iron mold locking device (10), wherein the upper iron mold (1) and the lower iron mold (2) are fixed by the iron mold locking device (10), characterized in that: The invention also comprises a coated sand shell mold (5) having an iron mold covered with sand and a backing iron mold covered with sand cavity (12), wherein the rotor screw casting is arranged axially vertically in the iron mold and is split in the middle; the supporting shaft (4) casting cavity at both ends of the rotor screw is formed by the iron mold covered with sand casting, and the screw spiral tooth surface (3) casting cavity of the rotor screw is formed by the coated sand shell mold (5) having a backing iron mold covered with sand.
2. The composite mold casting process device for screw compressor rotor screw casting according to claim 1, characterized in that: The pouring system (6) is in the form of a multi-branched center-injection water injection system, and the pouring system (6) comprises a straight runner (7), a bifurcated horizontal runner (8) and an inner runner (9).
3. The composite mold casting process device for screw compressor rotor screw casting according to claim 1, characterized in that: The thickness of the sand coating layer of the iron mold sand-coated casting mold cavity is 6-9 mm, the thickness of the sand coating layer of the backing iron mold sand-coated mold cavity (12) for placing the coated sand shell mold (5) is 3-4 mm, and the thickness of the sand coating layer of the pouring system (6) is 10-15 mm.
4. The composite mold casting process device for a screw compressor rotor screw casting according to claim 1, characterized in that: The outer conical surface of the shell mold (5) of the screw helical tooth surface (3) has a draft angle of 0.8°-1° at the lower part of the parting surface and a draft angle of 4°-5° at the upper part of the parting surface.
5. The composite mold casting process device for screw compressor rotor screw casting according to claim 4, characterized in that: The shell (5) of the screw helical tooth surface (3) has a shell thickness of 7-10 mm at the thinnest part.