Iron mold covered sand casting structure and manufacturing process of main shaft casting of large wind turbine generator set

Abstract

The present invention discloses an iron mold sand-coated casting structure and a manufacturing process thereof for a main shaft casting of a large wind turbine generator set, belonging to the field of casting technology, and comprising a double-group pouring system, a sand core structure, and a casting box, wherein a cavity is arranged inside the casting box, a sand-coated layer is arranged on the surface of the cavity, the sand core structure is arranged in the cavity inside the casting box, and a part of the double-group pouring system is arranged inside the casting box. The manufacturing process of the casting box comprises the following steps: making an upper sand core and a lower sand core, making a lower box, an iron mold sand-coated box, and an upper box, closing the box, making a straight runner, and setting a riser and a pouring basin. The present invention can reduce the volume of the casting box, reduce the heat transferred to the casting, and reduce the sand-iron ratio of the casting by arranging most of the straight runners in the double-group pouring system on the outside of the casting box, and the cone-shaped circumferential surface of the main shaft is formed by the iron mold sand-coated, thereby improving the chilling ability of the casting, reducing the production cost, and increasing the service life of the iron mold.

Description

Technical Field

[0001] The invention relates to an iron mold covered with sand casting structure of a main shaft casting of a large wind power generator set and a manufacturing process thereof, belonging to the technical field of casting. Background Art

[0002] The main shaft of a wind turbine generator is a key component that connects the wind rotor and the motor. When the wind blades are driven to rotate by the wind, the rotational power is transmitted to the generator through the main shaft. The main shaft bears the gravity and torque of the wind rotor, and its quality directly determines the stability and reliability of the wind turbine system. The main shaft of a large-scale high-power offshore wind turbine generator with a power of 9 to 12MW is made of QT500-14, with a bottom diameter of 2.5-3.5 meters, an upper diameter of 1.25-1.75 meters, a height of 2.8-4.8 meters, and a casting weight of 30-45 tons. Its working environment is harsh, and the quality of the main shaft casting is high. The reliability and safety of the casting are high. No casting defects are allowed, and the casting must be tested by UT and PT.

[0003] In the traditional casting method, the main shaft casting has a conical structure, a conical variable cross-section, a high height and thick wall. During the casting process, the mold box has a large demand for resin sand, and the number of cold irons that make up the outer cylindrical molding is large. This type of molding method consumes a large amount of sand and has a high sand-iron ratio of the casting. The heat of the pouring system is easy to diffuse from the pipe of the straight runner to the casting, affecting the cooling effect of the casting, causing defects such as pores, shrinkage cavities and shrinkage in the casting, affecting production efficiency and high production costs. When using iron molds to produce wind turbine main shafts, demolding is more difficult, affecting production efficiency and casting quality. In addition, the service life of the iron mold casting is 40-50 times. After reaching the limited number of times, the production quality of the castings that continue to be produced is not up to standard. The production method of the iron mold casting is relatively expensive. Therefore, it is necessary to develop and design an iron mold sand-covered casting structure and its manufacturing process suitable for the main shaft castings of large wind turbine generator sets, to improve the casting qualification rate, improve production efficiency, reduce the casting sand-iron ratio, reduce the number of molding cold irons, reduce production costs, and facilitate demolding of the iron mold sand-covered casting. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an iron mold covered sand casting structure and a manufacturing process for a main shaft casting of a large wind turbine generator set, which solves the problems of low casting qualification rate, high production cost, large amount of resin sand used and difficult demoulding during the manufacturing of the main shaft casting of a large wind turbine generator set.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solution: An iron mold covered with sand casting structure of a main shaft casting of a large wind turbine generator set, comprising:

[0006] Double group pouring system, sand core structure, casting box,

[0007] A cavity is provided inside the casting box, and the sand core structure is arranged in the cavity;

[0008] The casting box comprises an upper box, an iron mold covering sand box, and a lower box, the top of the lower box is provided with a groove, and the cavity surface of the iron mold covering sand box is provided with a covering sand layer; the bottom of the iron mold covering sand box is connected to the top of the lower box, the top of the iron mold covering sand box is provided with the upper box, and the double-group pouring system is connected to the lower box and is provided in the lower box;

[0009] The iron mold sand-covering box comprises an iron mold 1 and an iron mold 2, wherein the iron mold 1 comprises a half mold 1 and a half mold 2, wherein the iron mold 2 comprises a half mold 3 and a half mold 4, wherein the half mold 1 and the half mold 2 are fixed by a box buckle 1, wherein the half mold 3 and the half mold 4 are fixed by a box buckle 2, wherein the top and bottom of the iron mold 1 are respectively provided with a flange 1 and a flange 2, wherein the top and bottom of the iron mold 2 are respectively provided with a flange 3 and a flange 4, wherein the flange 2 and the flange 3 are fixed in position by a positioning stop and connected by bolts; a sand-covering layer is provided on the mold cavity surface of the iron mold sand-covering box;

[0010] The sand core structure comprises an upper sand core and a lower sand core, the lower sand core is arranged in the groove, and the upper sand core is fixed above the lower sand core through the groove;

[0011] The double-group pouring system includes: two groups of straight runners, multiple groups of cross runners, a liquid reservoir, and multiple groups of ingates. The ingates are connected to the cross runners through the liquid reservoir. The cross runners are composed of an upper cross runner and a lower cross runner. A ceramic filter is arranged between the upper cross runner and the lower cross runner. The liquid reservoir and multiple groups of upper cross runners are arranged inside the lower sand core. The lower cross runner and the ingates are arranged inside the lower box. The upper cross runner is arranged at the bottom of the lower sand core.

[0012] Preferably, the Huff mold 1, the Huff mold 2, the Huff mold 3 and the Huff mold 4 are provided with bosses at the fitting parts, and the fitting surfaces of the bosses are provided with positioning pins and positioning holes. The shapes of the box buckle 1 and the box buckle 2 are both wedges with grooves. The box buckle 1 and the box buckle 2 can fix the Huff mold 1 and the Huff mold 2, the Huff mold 3 and the Huff mold 4 respectively through the bosses formed at the fitting parts of the Huff mold 1 and the Huff mold 2, the Huff mold 3 and the Huff mold 4, and the thickness of the sand coating layer is 8-15mm.

[0013] Preferably, the sprue is divided into sprue one and sprue two, sprue one is vertically arranged above the lower box and passes through the lower box, sprue two is arranged at the bottom of the lower box, one side of sprue two is connected to the bottom of sprue one, and the other side of sprue two is connected to the liquid storage tank.

[0014] Preferably, one end of the ingrate is arranged on the inner side below the groove and connected to the lower runner, and the other end of the ingrate is arranged on the outer side below the groove.

[0015] Preferably, a sprue sleeve is provided on an outer side of the sprue disposed outside the lower box, and the sprue sleeve is fixed to the lower box via a flange.

[0016] Preferably, a pouring basin is provided on the top of each sprue sleeve.

[0017] Preferably, the cross-sectional area ratio between the runners is sprue: reservoir: runner: endogate = 1: (1.5-2.5): (1.5-2.5): (2.0-3.0).

[0018] Preferably, a cylindrical core bone and a molding core bone are arranged inside the upper sand core, and a molding core bone is arranged inside the lower sand core.

[0019] Preferably, the upper box is provided with an air outlet, and the air outlet is communicated with the cylindrical core bone.

[0020] Preferably, the manufacturing process is as follows:

[0021] The process of making upper sand core and lower sand core includes upper core box, lower core box, cylindrical core bone and forming core bone:

[0022] Step a: making the upper sand core, the upper core box is used to make the upper sand core, a cylindrical core bone is arranged at the center bottom of the upper core box, an exhaust rope is wound around the cylindrical core bone, and a molding chill is placed inside the upper core box and then sand is placed, the sand mold here needs to be compacted, the molding core bone is placed when the sand is placed close to the top of the upper sand core, the sand is placed and compacted continuously, the top plane of the upper core box is scraped flat, after the upper sand core is hardened, the core turning plate is locked, the upper core box is turned over and disassembled, and the outer surfaces of the upper sand core and the molding chill are repaired, cleaned and painted;

[0023] Step b: making the lower sand core, the lower core box is used to make the lower sand core, a layer of resin sand is placed at the bottom of the lower core box, and then the molded core bone is placed, and sand is continued to be placed to the upper end of the lower core box, and the top plane of the lower core box is scraped flat, and after the lower sand core is hardened, the lower core box is turned over and taken out, and the surface of the lower sand core is repaired, cleaned and coated;

[0024] The mold of the iron mold covered sand casting structure for making the main shaft casting of a large wind turbine generator set includes an upper mold and a lower mold. The upper mold and the lower mold are provided with a sand box positioning and a sand mold positioning inside:

[0025] Step 1: Make a lower box. The lower mold can make the lower box. The lower mold is provided with the inner runner and the second straight runner made of multiple ceramic tubes, as well as refractory bricks and formed chillers. Sand is placed in the lower mold and compacted. After the sand is placed, the mold is removed, the box is turned over, and the paint is applied after the resin sand is hardened. After the sand is placed in the lower box, a core head seat corresponding to the lower sand core and the upper sand core is formed;

[0026] Step 2: Assemble the iron mold sand-covering box and perform sand-covering: fit the half mold one and the half mold two together, connect and fix them according to the positioning pin and the positioning hole when fitting, and the box buckle one is buckled on the boss formed after the half mold one and the half mold two are fitted together; fit the half mold three and the half mold four together, connect and fix them according to the positioning pin and the positioning hole when fitting, and the box buckle two is buckled on the boss formed after the half mold three and the half mold four are fitted together; use a sand-covering core shooting machine to set a sand-covering layer on the inner cavity surface of the iron mold one, and use a sand-covering core shooting machine to set a sand-covering layer on the inner cavity surface of the iron mold two; use the positioning stop between the iron mold one and the iron mold two to fix the position through the flange two and the flange three, and use bolts to connect and fix;

[0027] Step 3: Make the upper box. The upper mold can make the upper box. The upper mold is provided with a pressure riser, an air outlet riser, an air outlet hole and a forming chill. After the sand is placed and compacted, the surface of the sand mold is scraped flat. After the resin sand is hardened, the upper box is demoulded, turned over and painted.

[0028] Step 4: Assemble the boxes, place the lower box in a flat pit, assemble the lower sand core into the lower box through the core head seat; place the upper sand core on the lower sand core through the core head seat; seal the box with a sealing mud strip on the parting surface of the lower box, connect the iron mold covering sand box with the lower box through the flange four, and connect the iron mold covering sand box with the upper box through the flange one;

[0029] Step 5: The sprue sleeve is arranged on the top of the lower box, connected to the sprue 2 of the lower box, the bottom of the sprue sleeve is fixed to the lower box through a flange, and the top of the sprue is fixed to the upper box through a flange, the sprue 1 is arranged inside the sprue sleeve, and filled with resin sand, the upper plane of the sprue sleeve is scraped flat, and after the resin sand is hardened, it is cleaned and polished, coated, ignited and dried;

[0030] Step 6: The upper box, the iron mold covering sand box, and the lower box are fastened with bolts, overflow risers are placed at the edge pressure risers and the air outlet risers of the upper box, and resin sand is used to reinforce the overflow risers; a gate basin is placed on the top of the sprue sleeve; and the cavity of the casting box is dried by a hot air blower.

[0031] The beneficial effects of the present invention are:

[0032] (1) According to the present invention, the sprue is arranged outside the casting box and the bottom is connected to the sand box, which can reduce the heat of the molten iron from the sprue side to the mold.

[0033] (2) According to the present invention, the sprue is arranged outside the mold box and fixed by a pipe sleeve, which can reduce the volume of the sand box, reduce the amount of sand consumed, and reduce the amount of molding chill.

[0034] (3) Through the present invention, the iron mold covering sand box structure is spliced ​​with two iron molds, and the iron mold adopts a half mold splitting method, and the box buckle is used to lock the iron mold at the joint, which is convenient for demolding the casting, improves production efficiency, and effectively prevents the casting from having quality problems such as box expansion and box leakage.

[0035] (4) Through the present invention, the sand coating layer covers the main surface of the casting box cavity, thereby improving the quenching ability of the casting, reducing the liquid shrinkage compensation amount of the riser, improving the metal liquid utilization rate, the surface hardness and wear resistance of the casting, and effectively preventing the casting from producing shrinkage holes and shrinkage defects, thereby increasing the service life of the iron mold of the iron mold sand coating box. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the present invention.

[0037] Figure 2 It is a structural schematic diagram of the lower box of the present invention.

[0038] Figure 3 It is a schematic diagram of the installation of the sand core structure of the present invention.

[0039] Figure 4 It is a schematic diagram of the installation of the iron mold 2 of the present invention.

[0040] Figure 5 It is a schematic diagram of the installation of the iron mold covering sand box of the present invention.

[0041] Figure 6 It is an internal cross-sectional view of the present invention.

[0042] Figure 7 It is a schematic diagram of the flipping structure of the double-group pouring system of the present invention.

[0043] Figure 8 It is a schematic diagram of the internal structure of the upper sand core of the present invention.

[0044] Fig. 9 It is a schematic diagram of the internal structure of the lower sand core of the present invention.

[0045] Fig.10 It is a structural schematic diagram of the upper core box of the present invention.

[0046] Fig.11 It is a schematic diagram of the structure of the Hough module 1 or the Hough module 2 of the present invention.

[0047] Fig.12 It is a structural schematic diagram of the Hough module three or the Hough module four of the present invention.

[0048] Fig.13 It is a schematic diagram of the box buckle structure of the present invention.

[0049] In the figure: 1-casting box, 101-lower box, 1011-boss box, 102-iron mold covering sand box, 1021-iron mold one, 1022-iron mold two, 103-upper box, 1031-riser, 104-box buckle one, 105-box buckle two, 2-sand core structure, 201-upper sand core, 202-lower sand core, 203-cylinder core bone, 204-molding core bone, 3-double group pouring system, 301-sprue, 3011-sprue one, 3012-sprue two, 302-liquid storage tank, 303-inner runner, 304 sprue sleeve, 305-gate basin, 306-lower cross runner, 4-upper core box, 5-locating pin, 6-locating hole DETAILED DESCRIPTION

[0050] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below in conjunction with specific embodiments.

[0051] Embodiment 1:

[0052] like Figure 1-13 As shown, an iron mold covered sand box casting structure of a main shaft casting of a large wind turbine generator set and a manufacturing process thereof, comprising: a casting box 1, a sand core structure 2, and a double-group pouring system 3. A cavity is arranged inside the casting box, the sand core structure 2 is arranged in the cavity inside the casting box 1, an air outlet is arranged on the top of the casting box 1, and the air outlet is connected to the sand core structure 2. A part of the double-group pouring system 3 is arranged inside the casting box 1, and the other part is arranged outside the casting box 1. The double-group pouring system 3 arranged inside the casting box 1 is connected to the bottom of the sand core structure 2, and the top of the sand core structure 2 is connected to the air outlet on the top of the casting box 1.

[0053] Reference Figure 2-Figure 6The casting box 1 comprises a lower box 101, an iron mold covering sand box 102, an upper box 103, a box buckle 104, and a box buckle 205. The iron mold covering sand box 102 is fixed on the top of the lower box 101, the upper box 103 is fixed on the top of the iron mold covering sand box 102, the box buckle 104 is installed on the lower half of the iron mold covering sand box 102, and the box buckle 205 is set on the upper half of the iron mold covering sand box 102. Figure 3 It can be seen that the shape of the lower box 101 is a truncated cone, and a boss box 1011 is arranged on the extension line of one diameter thereof, a double-group pouring system 3 is arranged inside the boss box 1011, an iron mold coating sand box 102 is arranged at the center of the lower box 101, and an upper box 103 is arranged on the top of the iron mold coating sand box 102.

[0054] The mold box 1 is provided with a mold cavity inside, and the mold cavity inside the mold box 1 can accommodate the sand core structure 2. The sand core structure 2 includes an upper sand core 201 and a lower sand core 202. The top of the lower box 101 is provided with a groove for fixing the lower sand core 202 and the upper sand core 201, and a core head seat for fixing the lower sand core 202 and the upper sand core 201 is provided inside the groove. The groove fixes the lower sand core 202 and the upper sand core 201 through the core head seat, and the lower sand core 202 and the upper sand core 201 are fixed to each other in the groove.

[0055] Reference Figure 6 The double-group pouring system 3 includes a sprue 301, a liquid reservoir 302, an inner runner 303, a sprue sleeve 304, a gate basin 305, and a cross runner. The sprue 301 includes a sprue 3011 and a sprue 3012. The second sprue 3012 is arranged in the boss box 1011. One end of the first sprue 3011 is fixed to the top of the boss box 1011 in the vertical direction. A part of the second sprue 3012 extends horizontally toward the center of the lower box 101 and is connected to the groove at the top of the lower box 101. There are two groups of the second sprue 3012, which are symmetrically arranged in the boss box 1011. The liquid reservoir 302 is the space formed by the groove at the top of the lower box 101 and the lower sand core 202. One end of the liquid reservoir 302 is connected to the second straight runner 3012, and the other end is connected to the upper runner, the upper runner is connected to the lower runner 306, and the lower runner 306 is connected to the inner runner 303. There are multiple upper runners and lower runners 306. There are multiple inner runners 303, all of which are connected to the groove at the top of the lower box 101, one end is connected to the inner side of the groove at the bottom of the lower box 101, and the other end is connected to the outer side of the groove at the bottom of the lower box 101.

[0056] The runner is divided into an upper runner and a lower runner 306, and there are multiple runners. The upper runner is a groove formed at the bottom of the lower sand core 202, and the lower runner 306 is arranged in a groove at the top of the groove of the lower box 101. The bottom of the lower runner is connected to the inner runner 303. The upper runner and the lower runner 306 together constitute a runner, and a ceramic filter is arranged between the upper runner and the lower runner 306.

[0057] The sprue sleeve 304 is vertically arranged above the boss box 1011, and a sprue 1 3011 is fixed inside the sprue sleeve 304 to fix and protect the sprue 1 3011. In this embodiment, the sprue sleeve 304 is composed of two sleeves, and flanges are arranged at both ends of the sprue sleeve 304; one end of the sprue sleeve 304 is connected to another sprue sleeve 304 by bolts, and the other end of the sprue sleeve 304 is fixed to the boss box 1011 by bolts, and the sprue sleeve 304 and the center of the sprue 2 3012 are fixed on the same axis. A pouring basin 305 is arranged on the top of the sprue sleeve 304.

[0058] The liquid reservoir 302 is a gap formed by the groove of the lower box 101 and the middle of the lower sand core 202 , and the bottom of the liquid reservoir 302 is connected to the second straight runner 3012 and the lower horizontal runner 306 .

[0059] The ratio of the cross sections between the runners is sprue: reservoir: runner: ingode = 1: (1.5-2.5): (1.5-2.5): (2.0-3.0). In this embodiment, the ratio of the cross sections between the runners of the double-group pouring system 3 is sprue: reservoir: runner: ingode = 1: 1.8: 1.5: 2.5 or sprue: reservoir: runner: ingode = 1: 2.2: 1.8: 2.5 or sprue: reservoir: runner: ingode = 1: 2.0: 1.8: 2.6, etc.

[0060] The double-group pouring system 3 is a bottom pouring open pouring system, specifically, the molten iron is poured from the pouring basin 305, and the molten iron flows from the sprue 301 into the liquid storage tank 302, and the liquid storage tank 302 can temporarily store the molten iron, and the molten iron in the liquid storage tank 302 is dispersed into the mold cavity through the cross runner and multiple inner runners 303 to form a casting. A foam ceramic filter is provided inside the cross runner, and the molten iron is filtered through the foam ceramic filter to remove the inclusions of the molten iron, purify the molten iron, and improve the quality of the casting.

[0061] Because the molten iron pressure is relatively large, and it is necessary to enter the mold cavity from the ingrow 303 at a low speed and a large flow rate, multiple ingrows 303 are used, and the cross-sectional diameter of the ingrow 303 is relatively large, so as to ensure that the molten iron quickly and steadily fills the mold cavity, and prevent the casting from having cold shut defects due to insufficient pouring. In this embodiment, 20 ingrows 303 are used. The number of ingrows 303 is adjusted according to the size of the casting. The M10 spindle casting has 20 groups of ingrows 303 and 20 groups of runners. The M12 spindle casting has 28 groups of ingrows 303 and runners, and the M8 spindle casting has 16 groups of ingrows 303 and runners.

[0062] Reference Figure 3 , Figure 6 The riser 1031 and the air outlet are arranged at the top of the upper box 103. There are multiple risers 1031 and one air outlet. In this embodiment, four risers 1031 are used, and the air outlet is connected to the cylindrical core 203. The riser 1031 is divided into a pressure edge riser, an air outlet riser, and an overflow riser.

[0063] In the casting box 1, a certain number of molded chills are arranged inside and outside the groove at the top of the lower box 101, and a core head seat for accommodating the lower sand core 202 is arranged inside the groove, and the top of the core head seat can fix the upper sand core 201. The lower sand core 202 and the upper sand core 201 are in contact with each other when installed in the groove. The lower sand core 202 is a hollow structure, and multiple horizontal runners extend outward from the hollow part in the middle. Molten iron can enter the horizontal runner from the center, and then flow into the ingrown 303 to enter the casting cavity.

[0064] Reference Figure 8 , Fig. 9 The upper sand core 201 is provided with a cylindrical core bone 203 and a molding core bone 204, and the lower sand core 202 is provided with a molding core bone 204. The surface of the cylindrical core bone 203 arranged on the upper sand core 201 has a plurality of holes, and when manufacturing the upper sand core 201, it is necessary to wrap an exhaust rope around the entire surface of the cylindrical core bone 203, so that the exhaust rope burns to form an exhaust channel when pouring molten iron, and the gas generated by the sand core and the cavity is discharged out of the mold through the cylindrical core bone 203 and the air outlet of the upper box 103 in time to prevent the casting from having air hole defects; when manufacturing the bottom of the upper sand core 201, it is necessary to pre-embed the molding core bone 204, and the molding core bone 204 can keep the upper sand core 201 stable and facilitate lifting and installation; when manufacturing the lower sand core 202, it is also necessary to pre-embed the molding core bone 204 to ensure the stability of the lower sand core 202.

[0065] Reference Figure 2-Figure 6 The structure of the casting box 1 from bottom to top is a lower box 101, an iron mold covered sand box 102, and an upper box 103. A double-group pouring system 3 is arranged inside the lower box 101, and a groove is arranged on the top. The groove fixes the sand core structure 2, and the upper sand core 201 is inside the iron mold covered sand box 102 except for the base, and is not connected to the iron mold covered sand box 102. The top of the upper sand core 201 is in contact with and communicated with the upper box 103, and the top of the cylindrical core bone 203 is connected with the air outlet of the upper box 103.

[0066] The iron mold covering sand box 102 includes an iron mold 1 1021 and an iron mold 2 1022 .

[0067] Reference Fig.11 , Fig.12 The iron mold 1 1021 includes a half mold 1 and a half mold 2, and the iron mold 2 1022 includes a half mold 3 and a half mold 4. The shape and structure of the half mold 1 are consistent with that of the half mold 2, and the shape and structure of the half mold 3 are consistent with that of the half mold 4.

[0068] The diameter of the bottom of the half mold three and the half mold four is the same as the size of the lower box 101. The fitting surface of the half mold three is provided with a positioning pin 5, and the fitting surface of the half mold four is provided with a positioning hole 6. The half mold three and the half mold four fit each other through the positioning pin 5 and the positioning hole 6, and the iron mold two 1022 is formed after fitting. The half mold three and the half mold four are both semicircular, and a boss extends at the fitting surface. The boss is located on the same plane as the fitting surface on one side of the fitting surface, and the width on the back of the fitting surface gradually increases as it moves away from the half mold three or the half mold four; after the half mold three and the half mold four are fitted together, two bosses of the same shape are formed, and the bosses are symmetrically arranged on the fitting surfaces of the half mold three and the half mold four. The second iron mold 1022 is fixed by a box buckle 104. The box buckle 104 is a wedge with a groove. The groove of the box buckle 104 is consistent with the boss of the second iron mold 1022. The box buckle 104 can be buckled on the boss of the second iron mold 1022 to fix the second iron mold 1022.

[0069] A positioning pin 5 is provided at the fitting surface of the half mold 1, and a positioning hole 6 is provided at the fitting surface of the half mold 2. The sides of the half mold 1 and the half mold 2 fit each other, and after fitting, an iron mold 1 1021 is formed. The half mold 1 and the half mold 2 are both semicircular, and a boss extends at the fitting surface. The boss is located on the same plane as the fitting surface on one side of the fitting surface, and the width on the back of the fitting surface gradually increases as it moves away from the half mold 1 or the half mold 2; after the half mold 1 and the half mold 2 are fitted, two bosses of the same shape are formed, and the bosses are symmetrically arranged on the fitting surfaces of the half mold 1 and the half mold 2. The iron mold 1 1021 is fixed by the box buckle 2 105, which is a wedge with a groove. The groove of the box buckle 2 105 is consistent with the boss of the iron mold 1 1021, and the box buckle 2 105 can be buckled on the boss of the iron mold 1 1021 to fix the iron mold 1 1021.

[0070] The half mold 1 and the half mold 2 are bonded to form the iron mold 1 1021, and the half mold 3 and the half mold 4 are bonded to form the iron mold 2 1022. The top and bottom of the iron mold 1 1021 and the iron mold 2 1022 are both provided with flanges. The bottom of the iron mold 1 1021 and the top of the iron mold 2 1022 are provided with positioning stoppers, and the iron mold 1 1021 and the iron mold 2 1022 are connected through the positioning stoppers and fixed with bolted flanges. The top of the iron mold 1 1021 is fixed to the upper box 103 by bolted flanges, and the bottom of the iron mold 2 1021 is fixed to the lower box 101 by bolted flanges.

[0071] As an implementation method, refer to Figures 11 to 13, the side bosses of the iron mold 1 1021 and the iron mold 2 1022 gradually increase in width from the top to the bottom, the boss at the bottom of the iron mold 1 1021 fits with the boss at the top of the iron mold 2 1022, and the boss width at the bottom of the iron mold 1 1021 is smaller than the boss at the top of the iron mold 2 1022. The box buckle 105 and the box buckle 2 104 correspond to the boss shapes of the iron mold 1 1021 and the iron mold 2 1022, respectively. When the box buckle 2 104 is fastened, it first fits the iron mold 2 1022, and the box buckle 2 104 slides from the top of the boss of the iron mold 2 1022 to the bottom to fasten; when the box buckle 105 is fastened, it first fits the iron mold 1 1021, and the box buckle 105 slides from the top of the boss of the iron mold 1 1021 to the bottom to fasten.

[0072] The iron mold sand-coating box 102 needs to use a sand-coating core shooting machine to shoot sand on the surface of the cavity inside the iron mold sand-coating box 102 and heat and solidify it into shape. After the sand coating is solidified, a layer of paint is sprayed on the surface of the sand coating, and the paint is zircon powder alcohol-based paint.

[0073] Reference Figure 3 , Figure 4 , Figure 5 The sizes of the connection parts of the iron mold 1 1021 and the iron mold 2 1022 are the same, and the upper sand core 201 is arranged at the center of the iron mold 1 1021 and the iron mold 2 1022 .

[0074] A manufacturing process of a resin sand casting structure for a main shaft casting of a large wind turbine generator set, the manufacturing process is as follows:

[0075] The process of making the upper sand core 201 and the lower sand core 202 includes: an upper core box 4 , a lower core box, a cylindrical core bone 203 , and a forming core bone 204 .

[0076] Step a: Refer to Figure 8 , Fig.10 , the upper sand core 201 is made, and the upper core box 4 is used to make the upper sand core 201. When making the upper sand core 201, the direction of the upper core box 4 making the upper sand core 201 is: the top of the upper sand core 201 is placed on the bottom of the upper core box 4, and the bottom of the upper sand core 201 is on the top of the upper core box 4, which is convenient for making the upper sand core 201 and ensuring the manufacturing quality of the upper sand core 201.

[0077] Specifically, firstly, one end of the cylindrical core bone 203 is vertically placed at the bottom of the upper core box 401 and is stabilized, the surface of the cylindrical core bone 203 is provided with a plurality of holes distributed along the surface of the cylindrical core bone 203, an exhaust rope is wound around the surface and holes of the cylindrical core bone 203, and a certain number of molded cold irons are arranged around the bottom of the upper core box 4 at the bottom of the upper core box 4; sand is placed inside the upper core box 4, and when the sand is placed to a distance exceeding one end of the top of the cylindrical core bone 203, the molded core bone 204 is placed, and the sand is continued to be placed to the top of the upper core box 4, and the top plane of the upper core box 4 is scraped flat, and after the upper sand core 201 is hardened, the top of the upper core box 4 is fixed with bolts to the core flip plate, and the upper core box 4 is flipped and the upper sand core 201 is taken out, and at this time, a certain number of molded cold irons are arranged on the top of the upper sand core 201. The surface of the upper sand core 201 is repaired and cleaned, and then painted with high temperature resistant alcohol-based paint, ignited, dried, polished, and cleaned for standby use.

[0078] Step b: Refer to Fig. 9 , make the lower sand core 202, the lower core box is used to make the lower sand core 202, place a layer of resin sand on the bottom of the lower core box to cover the pattern, then place the molded core bone 204, continue to put sand to the top of the lower core box, scrape the sand core plane of the lower core box flat, wait for the lower sand core 202 to harden, then take out the lower sand core 202, repair and clean the surface of the lower sand core 202, and then apply high temperature resistant alcohol-based paint, ignite, dry, polish and clean the high temperature resistant alcohol-based paint for use.

[0079] The iron mold covered sand box casting structure mold for making the main shaft casting of a large wind turbine generator set includes an upper mold and a lower mold. The inner sides of the upper mold and the lower mold are both provided with sand box positioning and sand mold positioning:

[0080] Step 1: Make the lower box 101. The lower mold is used to make the lower box 101. The lower mold is provided with multiple ingates 303 supported by ceramic tubes, a second straight runner 3012, a lower horizontal runner 306, refractory bricks and a molded chiller. The number of ingates 303 is multiple, and 20 are used in this embodiment. The number of second straight runners 3012 is 2, and the number of lower horizontal runners 306 is 20.

[0081] According to the internal positioning of the lower mold, the inner runner 303, the second straight runner 3012, the lower horizontal runner 306, the refractory bricks and the forming chiller are arranged. After the lower mold is formed by placing sand, the core heads of the lower sand core 202 and the upper sand core 201 are placed. At this time, the state of the lower box 101 in the lower mold is that the bottom is at the top and the top is at the bottom. Then, according to the positioning of the sand box, the sand is placed, and the mold is opened and the box is turned over after the resin sand hardens. The surface of the lower box 101 is repaired and cleaned, and then a high-temperature resistant alcohol-based paint is applied. The high-temperature resistant alcohol-based paint is ignited, dried, polished, cleaned, and then put into use.

[0082] Because a part of the double-group pouring system 3 is arranged below the lower box 101, when pouring directly on the lower box 101, the precision of the double-group pouring system 3 is not high and it is easy to offset. Therefore, when making the lower box 101, the lower box 101 is turned over to ensure the accuracy of the position of the double-group pouring system 3 inside the lower box 101, prevent the double-group pouring system 3 from offset, and facilitate the installation and fixation of the double-group pouring system 3.

[0083] Step 2: Assemble the iron mold sand box 102, which includes an iron mold 1 1021 and an iron mold 2 1022. The iron mold 1 1021 includes a half mold 1 and a half mold 2, and the iron mold 2 1022 includes a half mold 3 and a half mold 4. The half mold 1 and the half mold 2 confirm their positions according to the positioning pins 5 and 6 of the fitting surface, and after fitting, the iron mold 1 1021 is formed. The half mold 3 and the half mold 4 confirm their positions according to the positioning pins 5 and 6 of the fitting surface, and after fitting, the iron mold sand box 2 1022 is formed. The box buckle 2 104 slides from the top of the boss of the iron mold 2 1022 to the bottom for buckling; the box buckle 1 105 slides from the top of the boss of the iron mold 1 1021 to the bottom for buckling.

[0084] A sand coating core shooting machine is used to set a sand coating on the inner cavity surface of the iron mold 1021, and a sand coating core shooting machine is used to set a sand coating on the inner cavity surface of the iron mold 2 1022. The thickness of the sand coating is 12 mm in this embodiment. The iron mold 1 1021 and the iron mold 2 1022 are connected by a positioning stop and fixed by a bolt connection flange.

[0085] Step 3: Make the upper box. The upper mold is used to make the upper box. According to the positioning of the sand box, place the upper box 103 in the upper mold. Set the edge pressure riser, air outlet riser, air outlet hole and forming cold iron according to the positioning method of the upper mold, and place resin sand. After the sand is placed and compacted, the top of the upper box 103 is scraped flat. After the resin sand is hardened, the upper box 103 is taken out of the upper mold, and the surface of the upper box 1031 is repaired and cleaned, and then painted with high temperature resistant alcohol-based paint, ignited, dried, polished, cleaned and set aside.

[0086] Step 4: Assemble the boxes, place the lower box 101 in a flat pit with the groove facing upward; set a certain number of ceramic filter sheets inside the lower runner 306; set the lower sand core 202 and the upper sand core 201 in the groove of the lower box 101 according to the core head seat. The flange at the bottom of the iron mold sand box 102 is fixed to the flange at the top of the lower box 101 by bolts, and does not contact the upper sand core 201. The top of the iron mold sand box 102 is fixed to the upper box 103 by a flange, and the air outlet at the center of the upper box 103 is connected and fixed to the cylindrical core bone 203 of the upper sand core 201.

[0087] Step 5: Make the sprue 1 3011 and the sprue sleeve 304. The sprue sleeve 304 in this embodiment uses two sleeves of the same type, both ends of the sleeves are provided with flanges, and one end of the two sleeves is connected and fixed by the flange to form the sprue sleeve 304. The sprue 1 3011 is set inside the sprue sleeve 304, and resin sand molding is filled between the sprue sleeve 304. After the resin sand is hardened, the upper and lower ends of the sprue sleeve 304 are scraped flat, painted, ignited and dried, and then used.

[0088] Step 6: Fix the bottom flange of the sprue sleeve 304 to the boss box 1011 by bolts, and connect the sprue 1 3011 and the sprue 2 3012 to each other.

[0089] Step 7: Sealing mud strips are set on the connection surfaces between the lower box 101, the iron mold covering sand box 102, and the upper box 103, and the edge pressure riser and the air outlet riser are set on the top of the upper box 103, and the edge pressure riser and the air outlet riser are hardened and surrounded by resin sand. A pouring basin 305 is set on the top of the sprue sleeve 304, and the entrance of the pouring basin 305 is connected to the sprue 2 3012. A hot air blower is connected to the pouring basin to dry the cavity in the casting box, further harden the resin sand casting, and eliminate the moisture inside the casting.

[0090] Shaping of the spindle casting: Melting metal materials, adjusting the chemical composition and temperature of the molten iron, after spheroidizing and inoculating treatment, pouring qualified molten metal from the pouring basins 305 on both sides simultaneously, so that the molten metal fills the mold cavity and the pouring and riser system, and after the molten metal solidifies, cools and keeps warm for a period of time, disconnecting the upper box 103, the iron mold covering sand box 102, and the lower box 101, unpacking, cleaning with sand removal, and shot blasting to obtain the spindle casting.

[0091] In this embodiment, the straight runner is set on the side of the casting and connected to the casting box, and pouring is performed from the bottom of the casting. Compared with the traditional casting method, the resin sand set at the casting box is reduced, the number of cold irons that make up the outer cylindrical molding is reduced, the sand consumption is greatly reduced, and the sand-iron ratio of the casting is low; it effectively prevents the heat of the pouring system from easily diffusing from the straight runner pipe to the casting, accelerates the cooling effect of the casting, and prevents the casting from having defects such as pores, shrinkage cavities, and shrinkage.

[0092] A layer of sand coating is provided on the cavity surface of the iron mold sand coating box, which can improve the chilling ability of the casting structure, and the iron mold sand coating box is composed of iron mold 1 and iron mold 2, iron mold 1 includes half mold 1 and half mold 2, and iron mold 2 includes half mold 3 and half mold 4. The iron mold sand coating box is composed of four half molds, which is convenient for demoulding. A sand coating layer of a certain thickness is provided at the contact surface between the iron mold sand coating box and the casting to prevent the molten iron from directly contacting the iron mold sand coating box, which can increase the number of times the iron mold sand coating box is used.

[0093] The basic principles, main features and advantages of the present invention are shown and described above. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. An iron mold covered sand casting structure for a main shaft casting of a large wind turbine generator set, comprising: Double group pouring system, sand core structure, casting box, A cavity is provided inside the casting box, and the sand core structure is arranged in the cavity; Features: The casting box comprises an upper box, an iron mold covering sand box, and a lower box, the top of the lower box is provided with a groove, and the cavity surface of the iron mold covering sand box is provided with a covering sand layer; the bottom of the iron mold covering sand box is connected to the top of the lower box, the top of the iron mold covering sand box is provided with the upper box, and the double-group pouring system is connected to the lower box and is provided in the lower box; The iron mold sand-covering box includes an iron mold 1 and an iron mold 2, the iron mold 1 includes a half mold 1 and a half mold 2, the iron mold 2 includes a half mold 3 and a half mold 4, the half mold 1 and the half mold 2 are fixed by a box buckle 1, the half mold 3 and the half mold 4 are fixed by a box buckle 2, the top and bottom of the iron mold 1 are respectively provided with a flange 1 and a flange 2, the top and bottom of the iron mold 2 are respectively provided with a flange 3 and a flange 4, the flange 2 and the flange 3 are fixed in position by a positioning stop and connected with bolts; The sand core structure comprises an upper sand core and a lower sand core, wherein the lower sand core is arranged in the groove, and the upper sand core is fixed above the lower sand core; The double-group pouring system comprises: two groups of sprues, multiple groups of cross runners, a liquid reservoir, and multiple groups of ingates, wherein the ingates are connected to the liquid reservoir through the cross runners, the cross runners are composed of an upper cross runner and a lower cross runner, a ceramic filter is arranged between the upper cross runner and the lower cross runner, the liquid reservoir and multiple groups of the upper cross runners are arranged inside the lower sand core, the lower cross runners and the ingates are arranged inside the lower box, and the upper cross runner is arranged at the bottom of the lower sand core; The half mold 1, the half mold 2, the half mold 3 and the half mold 4 are provided with bosses at the fitting parts, and the fitting surfaces of the bosses are provided with positioning pins and positioning holes. The shapes of the box buckle 1 and the box buckle 2 are both wedge-shaped with grooves. The box buckle 1 and the box buckle 2 can fix the half mold 1 and the half mold 2, the half mold 3 and the half mold 4 through the bosses formed at the fitting parts of the half mold 1 and the half mold 2, the half mold 3 and the half mold 4, respectively. The thickness of the sand coating layer is 8-15mm; The sprue is divided into sprue 1 and sprue 2, the sprue 1 is vertically arranged above the lower box and passes through the lower box, the sprue 2 is arranged at the bottom of the lower box, one side of the sprue 2 is connected to the bottom of the sprue 1, and the other side of the sprue 2 is connected to the liquid storage tank; A sprue sleeve is arranged on the outer side of the sprue arranged outside the lower box, and the sprue sleeve is fixed to the lower box through a flange; The top of the sprue sleeve is provided with a pouring basin; The cross-sectional area ratio between each runner is sprue: reservoir: runner: endogate = 1: (1.5-2.5): (1.5-2.5): (2.0-3.0); One end of the ingrate is arranged on the inner side below the groove and connected to the lower runner, and the other end of the ingrate is arranged on the outer side below the groove.

2. The iron mold covered sand casting structure of a main shaft casting of a large wind turbine generator set according to claim 1, characterized in that: The upper sand core is provided with a cylindrical core bone and a forming core bone, and the lower sand core is provided with a forming core bone.

3. The iron mold covered sand casting structure of the main shaft casting of a large wind turbine generator set according to claim 2, characterized in that: The upper box is provided with an air outlet, and the air outlet is communicated with the cylindrical core bone.

4. A process for manufacturing an iron mold covered with sand casting structure for a main shaft casting of a large wind turbine generator set according to any one of claims 1 to 3, characterized in that: The production process is as follows: The process of making the upper sand core and the lower sand core includes an upper core box, a lower core box, a cylindrical core bone, and a forming core bone, and the steps are as follows: Step a: making the upper sand core, the upper core box is used to make the upper sand core, a cylindrical core bone is arranged at the center bottom of the upper core box, an exhaust rope is wound around the cylindrical core bone, and a molding chill is placed inside the upper core box and then sand is placed, the sand mold here needs to be compacted, the molding core bone is placed when the sand is placed close to the top of the upper sand core, the sand is placed and compacted continuously, the top plane of the upper core box is scraped flat, after the upper sand core is hardened, the core turning plate is locked, the upper core box is turned over and disassembled, and the outer surfaces of the upper sand core and the molding chill are repaired, cleaned and painted; Step b: making the lower sand core, the lower core box is used to make the lower sand core, a layer of resin sand is placed at the bottom of the lower core box, and then the molded core bone is placed, and sand is continued to be placed to the upper end of the lower core box, and the top plane of the lower core box is scraped flat, and after the lower sand core is hardened, the lower core box is turned over and taken out, and the surface of the lower sand core is repaired, cleaned and coated; The mold of the iron mold covered sand casting structure for making the main shaft casting of a large wind turbine generator set includes an upper mold and a lower mold. The upper mold and the lower mold are provided with a sand box positioning and a sand mold positioning inside: Step 1: Make a lower box. The lower mold can make the lower box. The lower mold is provided with the inner runner, the lower horizontal runner and the second straight runner made of multiple ceramic tubes, as well as refractory bricks and formed chillers. Sand is placed on the surface of the lower mold and compacted. After the sand is placed, the resin sand is hardened, and the mold is removed, the box is turned over, and the paint is applied. After the sand is placed in the lower box, a core head seat corresponding to the lower sand core and the upper sand core is formed; Step 2: Assemble the iron mold sand-covering box and perform sand-covering: fit the half mold one and the half mold two together, connect and fix them according to the positioning pin and the positioning hole when fitting, and the box buckle one is buckled on the boss formed after the half mold one and the half mold two are fitted together; fit the half mold three and the half mold four together, connect and fix them according to the positioning pin and the positioning hole when fitting, and the box buckle two is buckled on the boss formed after the half mold three and the half mold four are fitted together; use a sand-covering core shooting machine to set a sand-covering layer on the inner cavity surface of the iron mold one, and use a sand-covering core shooting machine to set a sand-covering layer on the inner cavity surface of the iron mold two; use the positioning stop between the iron mold one and the iron mold two to fix the position through the flange two and the flange three, and use bolts to connect and fix; Step 3: Make the upper box. The upper mold can make the upper box. The surface of the upper mold is provided with a pressure riser, an air outlet riser, an air outlet hole and a forming chill. After the sand is placed and compacted, the surface of the sand mold is scraped flat. After the resin sand is hardened, the upper box is demoulded, turned over and painted. Step 4: Assemble the boxes, place the lower box in a flat pit, place a ceramic filter at the lower cross runner of the lower box, assemble the lower sand core into the lower box through the core head seat; place the upper sand core on the lower sand core through the core head seat; seal the parting surface of the lower box with a sealing mud strip, connect the iron mold covering sand box with the lower box through the flange four, and connect the iron mold covering sand box with the upper box through the flange one; Step 5: The sprue sleeve is arranged on the top of the lower box, connected to the sprue 2 of the lower box, the bottom of the sprue sleeve is fixed to the lower box through a flange, the sprue 1 is arranged inside the sprue sleeve, and filled with resin sand, the upper plane of the sprue sleeve is scraped flat, and after the resin sand is hardened, it is cleaned and polished, coated, ignited and dried; Step 6: The upper box, the iron mold covering sand box, and the lower box are fastened with bolts, overflow risers are placed at the edge pressure risers and the air outlet risers of the upper box, and resin sand is used to reinforce the overflow risers; a gate basin is placed on the top of the sprue sleeve; and the cavity of the casting box is dried by a hot air blower.

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