Special sand box for casting wind power hub

Abstract

The utility model discloses a special sand box for casting a wind power hub, which belongs to the technical field of V-method casting and comprises a hub sand box assembly, a hub mold can be arranged in the hub sand box assembly and is assembled with a pouring system, a pouring cup system is arranged at the top of the hub sand box assembly, and the pouring cup system is connected with the hub sand box assembly. And a pouring pipeline of the pouring system can extend out of the top of the hub sand box assembly to be communicated with the pouring cup system. The utility model provides a special sand box for casting a wind power hub, which adopts a cavity structure consisting of a sand box outer plate, a sand box inner plate, an upper connecting plate and a lower connecting plate, the sand box outer plate and the sand box inner plate are connected together through a plurality of support rods in a welding manner, and a hub sand box assembly of a sand box belt is arranged at the bottom of a hexagonal upper sand box. The inner lining steel plate and the outer lining steel plate of the sand box are ensured to be balanced and equal in stress, the strength of the sand box is ensured to meet the design requirement, and the problems of box expansion, run-out, box leakage, casting shrinkage porosity, safety accidents and the like caused by molding of castings which are more than 5 tons per piece are solved.

Description

Technical Field

[0001] The utility model discloses a special sand box for casting a wind turbine hub, belonging to the technical field of V-method casting. Background Art

[0002] The existing V-method process uses silica sand without adding any chemical binder, and evacuates the sand box to form the sand mold required by the casting process under vacuum negative pressure. The V-method casting process in the current industry only produces small castings with simple structures below 5 tons, such as locomotives, elevator counterweights, light and heavy trucks, and train axles. It has the advantages of low cost, superior production environment, and high efficiency. It is the preferred method for conventional production processes of many foundry companies.

[0003] So far, the foundry industry has been producing large-scale high-end wind power castings using traditional resin sand casting technology. The process of adding chemical adhesives and curing agents (furan resin and sulfonic acid curing agent) to silica sand to produce chemical reactions over a certain period of time to make the sand mold self-harden and meet the molding requirements of the process. This process has been used for more than 60 years and is still the mainstream process for the current production of medium and large castings. With the development of industry and the advancement of technology, resource shortages are becoming increasingly serious, people's living standards and health awareness are constantly improving, environmental awareness is strengthened, and production costs are increasing year by year. As the industry's production capacity increases, the competition for castings sold becomes fierce, corporate profits are getting lower and lower, and the survival crisis is becoming more urgent.

[0004] So far, there are no cases in the industry or in the world that use the V-method casting process to produce wind power ductile iron castings weighing more than 5 tons. The production of castings weighing more than 5 tons is prone to problems such as bulging, collapsing, fire leakage, shrinkage of castings and safety accidents. Utility Model Content

[0005] The utility model aims to solve the problems of box expansion, box collapse, fire leakage, casting shrinkage and safety accidents in the existing production of castings with a single weight of more than 5 tons, and proposes a special sand box for casting wind turbine hubs.

[0006] The problem to be solved by the utility model is achieved by the following technical solutions:

[0007] A special sand box for casting a wind turbine hub comprises a hub sand box assembly, wherein a hub mold can be arranged inside the hub sand box assembly, the hub mold is assembled with a pouring system, a pouring cup system is arranged on the top of the hub sand box assembly, and a pouring pipe of the pouring system can extend out of the top of the hub sand box assembly and communicate with the pouring cup system.

[0008] Preferably, the wheel hub sand box assembly includes a hexagonal upper sand box and a hexagonal lower sand box with the same structure and capable of interlocking with each other. The hexagonal upper sand box and the hexagonal lower sand box are locked by cooperating with bolts and nuts through multiple uniform positioning grooves on the edge of the opening. The hexagonal upper sand box and the hexagonal lower sand box are positioned by cooperating with positioning pins and positioning pin sleeves through any pair of symmetrical sides at the opening.

[0009] Preferably, the side of the hexagonal upper sand box is a hollow structure composed of a sand box outer plate, a sand box inner plate and two upper and lower connecting plates, the sand box outer plate and the sand box inner plate are connected together by a number of support rods, a sand box belt is provided at the bottom of the hexagonal upper sand box, horizontal and vertical reinforcing ribs are arranged on the outside of the sand box outer plate, two lifting and flipping ears are arranged on the six faces of the sand box outer plate, and negative pressure exhaust connection pipe joints passing through the sand box outer plate and the sand box inner plate in sequence are provided on the six faces of the sand box outer plate except for the positioning seats, and the top of the hexagonal upper sand box and the bottom of the hexagonal lower sand box are respectively provided with an upper triangular fixed arm and a lower triangular fixed arm, and the upper triangular fixed arm and the lower triangular fixed arm are respectively connected together by three triangular arm connecting plates.

[0010] Preferably, the inner side of the sand box outer plate is provided with a plurality of positioning support rod positioning blind holes for positioning the large diameter end of the support rod, and the side of the sand box inner plate is provided with a plurality of positioning support rod positioning through holes for positioning the small diameter end of the support rod.

[0011] Preferably, the pouring cup system includes a pouring cup sand box, refractory bricks are arranged on the inner side of the pouring cup sand box, and a hook support and a fixed support are respectively provided on the outer side of the pouring cup sand box, the hook support and the fixed support are successively penetrated by guide shafts parallel to the side of the pouring cup sand box, the end of the hook support is hinged to the middle part of the lever handle, one end of the lever handle is hinged to the side of the guide shaft between the hook support and the fixed support, the end of the guide shaft close to the fixed support is vertically connected to one end of the upper support rod, the other end of the upper support rod is vertically connected to one end of the stopper rod, a sleeve brick is sleeved on the stopper rod, and a pouring hole connected to one end of the pouring pipe is provided at the bottom of the pouring cup sand box, and the end of the sleeve brick can cooperate with the pouring hole.

[0012] Preferably, the hub mold comprises an upper hub mold and a lower hub mold with air holes which are interlocked with each other, the main shaft mounting surface of the upper hub mold is evenly arranged with at least 6 air hole columns and a plurality of first cold iron blocks, the main shaft mounting surface of the lower hub mold is evenly arranged with a plurality of casting connecting columns, the outer and inner sides of the three variable pitch bearing mounting surfaces formed by the upper hub mold and the lower hub mold are arranged with a plurality of second cold iron blocks, and the main shaft mounting surface of the lower hub mold is evenly arranged with a plurality of third cold iron blocks.

[0013] Preferably, the pouring system includes a pouring accommodating shell arranged in an inner hole of the main shaft mounting surface of the lower hub mold, a distribution plate is snapped on the top of the pouring accommodating shell, the distribution plate is connected to one end of a plurality of distribution pipes through a plurality of connecting holes evenly arranged, the other ends of the plurality of distribution pipes are connected to a plurality of pouring connecting columns, a middle hole is provided in the middle of the distribution plate to connect to the other end of the pouring pipe, and the pouring pipe is respectively connected to the plurality of distribution pipes through the cavity formed by the pouring accommodating shell and the distribution plate.

[0014] The utility model has the following beneficial effects compared with the prior art:

[0015] The utility model provides a special sand box for casting a wind turbine hub. Through a cavity structure composed of a sand box outer plate, a sand box inner plate and two upper and lower connecting plates, the sand box outer plate and the sand box inner plate are connected together by welding through a plurality of supporting rods. A hub sand box assembly with a sand box belt is arranged at the bottom of the hexagonal upper sand box to ensure that the force balance of the inner lining steel plate and the outer lining steel plate of the sand box is equal, and the strength of the sand box meets the design requirements, which solves the problems of bulging box, collapsing box, fire leakage, shrinkage of castings and safety accidents in the production of castings with a weight of more than 5 tons. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The utility model is an isometric side view of a special sand box for casting a wind turbine hub.

[0017] Figure 2 The utility model is an isometric side view of a wheel hub sand box assembly in a special sand box for casting a wind turbine wheel hub.

[0018] Figure 3 It is an enlarged view of point A of the present utility model.

[0019] Figure 4 The utility model is an isometric side view of a special sand box for casting a wind turbine hub.

[0020] Figure 5 It is a front view of a hexagonal upper sand box in a special sand box for casting a wind turbine hub of the utility model.

[0021] Figure 6 The utility model is a side view of a hexagonal upper sand box in a special sand box for casting a wind turbine hub.

[0022] Figure 7 The utility model is a cross-sectional view of a hexagonal upper sand box in a special sand box for casting a wind turbine hub.

[0023] Figure 8 It is an enlarged view of B of the utility model.

[0024] Fig. 9The utility model is an isometric view of a pouring cup system in a sand box specially used for casting a wind turbine hub.

[0025] Fig.10 It is a partial isometric view of a pouring cup system in a sand box specially used for casting a wind turbine hub according to the utility model.

[0026] Fig.11 It is a partial isometric view of a pouring cup system in a sand box specially used for casting a wind turbine hub according to the utility model.

[0027] Fig.12 It is a partial isometric side view of a special sand box for casting a wind turbine hub according to the utility model.

[0028] Fig.13 It is a partial isometric side view of a special sand box for casting a wind turbine hub according to the utility model.

[0029] Fig.14 It is a partial isometric side view of a lower hub mold in a sand box specially used for casting a wind turbine hub of the utility model.

[0030] Fig.15 The utility model is an isometric view of a pouring system in a sand box specially used for casting a wind turbine hub.

[0031] Among them, 100- pouring cup system, 200- wheel hub sand box assembly, 300- wheel hub mold, 400- pouring system, 13- connecting rod, 101- pouring cup sand box, 102- refractory brick, 103- sleeve brick, 104- plug rod, 105- upper support rod, 106- fixed support, 107- guide shaft, 108- lever handle, 109- hook support, 110- pouring hole, 201- upper triangular fixed arm, 202- triangular arm connecting plate, 203- hexagonal upper sand box, 204- hexagonal lower sand box, 205- lower triangular fixed arm, 206- positioning pin sleeve, 207- fixed Position pin, 208-lifting and flipping ear, 209-connecting plate, 210-positioning seat, 211-sand box belt, 212-negative pressure exhaust connecting pipe joint, 213-positioning groove, 214-reinforcement rib, 215-sand box outer plate, 216-support rod, 217-sand box inner plate, 301-air permeable column, 302-first cold iron block, 303-upper hub mold, 304-second cold iron block, 305-lower hub mold, 306-third cold iron block, 307-casting connecting column, 401-casting connecting column, 402-distribution plate, 403-distribution pipe, 404-casting containing shell. DETAILED DESCRIPTION

[0032] The following is based on the attached Figure 1-15 The utility model is further described as follows:

[0033] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] like Figure 1 and 15 As shown, the first embodiment of the utility model provides a special sand box for casting wind turbine hub on the basis of the prior art, including a hub sand box assembly 200, in which a hub mold 300 can be placed, the hub mold 300 is assembled with a pouring system 400, and a pouring cup system 100 is installed on the top of the hub sand box assembly 200, and a pouring pipe 401 of the pouring system 400 can extend out of the top of the hub sand box assembly 200 and communicate with the pouring cup system 100.

[0037] like Figure 2-8As shown, the hub sand box assembly 200 includes a hexagonal upper sand box 203 and a hexagonal lower sand box 204 with the same structure and capable of interlocking with each other. The hexagonal upper sand box 203 and the hexagonal lower sand box 204 are locked by multiple uniform positioning grooves 213 on the edge of the opening in cooperation with bolts and nuts. The hexagonal upper sand box 203 and the hexagonal lower sand box 204 are positioned by installing a positioning seat 210 and a positioning pin 207 and a positioning pin sleeve 206 on any pair of symmetrical sides of the opening respectively. An upper triangular fixing arm 201 and a lower triangular fixing arm 205 are installed on the top of the hexagonal upper sand box 203 and the bottom of the hexagonal lower sand box 204 respectively. The upper triangular fixing arm 201 and the lower triangular fixing arm 205 are connected together by three triangular arm connecting plates 202 respectively.

[0038] The side of the hexagonal upper sand box 203 is a cavity structure composed of a sand box outer plate 215, a sand box inner plate 217 and two upper and lower connecting plates 209. The sand box outer plate 215 and the sand box inner plate 217 are welded together by a number of support rods 216. A sand box belt 211 is installed at the bottom of the hexagonal upper sand box 203. The outer side of the sand box outer plate 215 is arranged with horizontal and vertical reinforcing ribs 214 to ensure that the sand box outer plate 215 and the sand box inner plate 217 are equally balanced in force and the sand box strength meets the design requirements. The six faces of the sand box outer plate 215 are arranged with two lifting and flipping ears 208. The other faces of the six faces of the sand box outer plate 215 except the positioning seat 210 are installed with negative pressure exhaust connection pipe joints 212 that pass through the sand box outer plate 215 and the sand box inner plate 217 in sequence. A plurality of blind holes 2151 for positioning the large diameter end of the support rod 216 are provided on the inner side of the sand box outer plate 215 , and a plurality of through holes 2171 for positioning the small diameter end of the support rod 216 are provided on the side of the sand box inner plate 217 .

[0039] like Figure 9-11 As shown, the pouring cup system 100 includes a pouring cup sand box 101, the inner side of the pouring cup sand box 101 is arranged with refractory bricks 102, the outer side of the pouring cup sand box (101) is respectively installed with a hook support 109 and a fixed support 106, the hook support 109 and the fixed support 106 are successively penetrated with a guide shaft 107 parallel to the side of the pouring cup sand box 101, the end of the hook support 109 is hinged to the middle of the lever handle 108, and one end of the lever handle 108 is hinged to the hook support 109. The guide shaft 107 between the hook support 109 and the fixed support 106 is hinged at the side, and the end of the guide shaft 107 close to the fixed support 106 is vertically connected to one end of the upper support rod 105, and the other end of the upper support rod 105 is vertically connected to one end of the stopper rod 104. A sleeve brick 103 is sleeved on the stopper rod 104, and a pouring hole 103 connected to one end of the pouring pipe 401 is provided at the bottom of the pouring cup sand box 101, and the end of the sleeve brick 103 can cooperate with the pouring hole 110.

[0040] like Figure 12-14As shown, the hub mold 300 includes an upper hub mold 303 and a lower hub mold 305 with air holes that are interlocked with each other, the main shaft mounting surface of the upper hub mold 303 is evenly arranged with at least 6 air hole columns 301 and a plurality of first cold iron blocks 302, the main shaft mounting surface of the lower hub mold 305 is evenly arranged with a plurality of casting connecting columns 307, the outer and inner sides of the three variable pitch bearing mounting surfaces formed by the upper hub mold 303 and the lower hub mold 305 are evenly arranged with a plurality of second cold iron blocks 304, and the main shaft mounting surface of the lower hub mold 305 is evenly arranged with a plurality of third cold iron blocks 306.

[0041] like Fig.15 As shown, the pouring system 400 includes a pouring accommodating shell 404 installed in the inner hole of the main shaft mounting surface of the lower hub mold 305, and a distribution plate 402 is snapped on the top of the pouring accommodating shell 404. The distribution plate 402 is connected to one end of multiple distribution pipes 403 through multiple connection holes evenly arranged, and the other ends of the multiple distribution pipes 403 are connected to multiple pouring connecting columns 307. A middle hole is provided in the middle of the distribution plate 402 to connect to the other end of the pouring pipe 401, and the pouring pipe 401 is connected to the multiple distribution pipes 403 respectively through the cavity formed by the pouring accommodating shell 404 and the distribution plate 402.

[0042] The second embodiment of the utility model provides a V-method casting method for a wind turbine hub based on the prior art, which is applied to a special sand box for casting a wind turbine hub described in the first embodiment, comprising:

[0043] Step S1, prepare the upper wheel hub mold 303 and the lower wheel hub mold 305 respectively, and connect the upper wheel hub mold 303 and the lower wheel hub mold 305 to the exhaust equipment respectively.

[0044] Step S2, heat the special EVA film to 60-70 degrees for 150-210 seconds, and coat the upper hub mold 303 and the lower hub mold 305. After the film is heated, use the vacuum equipment to make the EVA film fit tightly with the upper hub mold 303 and the lower hub mold 305 through the air holes. After the coating is completed, connect to the casting system 400.

[0045] Step S3, spraying paint on the upper hub mold 303 and the lower hub mold 305 with the pouring system 400, and drying the paint with a drying device.

[0046] Step S4, respectively place the air-permeable column 301, the first cold iron block 302, the second cold iron block 304 and the third cold iron block 306 on the outside of the coating, respectively place the upper hub mold 303, the lower hub mold 305 and the corresponding pouring system 400 in the hexagonal upper sand box 203 and the hexagonal lower sand box 204, respectively fill the hexagonal upper sand box 203 and the hexagonal lower sand box 204 with dry sand, connect the outer sides of the hexagonal upper sand box 203 and the hexagonal lower sand box 204 to the exhaust equipment, the dry sand is 20-70 mesh silica sand, and the coating thickness of the coating is 3-5mm.

[0047] Step S5, start the vibration equipment, use the three-dimensional vibration equipment to vibrate the sand box with a rhythmic frequency, ensure that the silica sand in the sand box is balanced and compacted, ensure that the dry sand in the hexagonal upper sand box 203 and the hexagonal lower sand box 204 is compacted, vacuumize, use the pressure difference inside and outside the sand mold to make the sand mold compact, and stop the vacuuming operation of the upper hub mold 303 and the lower hub mold 305. The vacuuming pressure is a negative pressure of 0.04-0.09, and the vibration time is about 4-10 minutes.

[0048] Step S6, after the sand mold is compacted, cover the hexagonal upper sand box 203 and the hexagonal lower sand box 204 with a plastic film to ensure that the sand molds in the hexagonal upper sand box 203 and the hexagonal lower sand box 204 are in a closed space, separate the compacted hexagonal upper sand box 203 and the hexagonal lower sand box 204 from the air vent column 301, the upper wheel hub mold 303 and the lower wheel hub mold 305, flip the hexagonal upper sand box 203 and the hexagonal lower sand box 204 over and place them stably on the sand bed, completing the operation of the hexagonal upper sand box 203 and the hexagonal lower sand box 204.

[0049] Step S7, dropping the upper sand core and the lower sand core made in advance into the hexagonal upper sand box 203 and the hexagonal lower sand box 204 to perform the core closing operation.

[0050] Step S8, install the pouring cup system 100, and pouring can be carried out after the hexagonal upper sand box 203 and the hexagonal lower sand box 204 are inspected and assembled, which shortens the solidification time of resin sand, improves production efficiency, and reduces labor costs. Qualified molten iron is smelted according to the standard ingredients of casting materials, and poured into the assembled casting mold through a special pouring cup with quantitative controllable flow rate. During the pouring process, the negative pressure pipes of the hexagonal upper sand box 203 and the hexagonal lower sand box 204 are in a vacuum state throughout the whole process, which is conducive to the emission of harmful gases, purifies the working environment, and reduces occupational hazards. After the metal solidifies, stop evacuating the cavity until the pressure in the cavity is equal to the external pressure, the cavity collapses, and the casting is obtained. That is, after the insulation and cooling meet the process requirements, the required castings are unpacked and taken out, polished and shot blasted, and then delivered to the processing process or customers.

[0051] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A special sand box for casting wind turbine hub, characterized in that: The invention comprises a wheel hub sand box assembly (200), wherein a wheel hub mold (300) can be arranged inside the wheel hub sand box assembly (200), the wheel hub mold (300) is assembled with a pouring system (400), a pouring cup system (100) is arranged on the top of the wheel hub sand box assembly (200), and a pouring pipe (401) of the pouring system (400) can extend out of the top of the wheel hub sand box assembly (200) and communicate with the pouring cup system (100).

2. A special sand box for casting a wind turbine hub according to claim 1, characterized in that: The wheel hub sand box assembly (200) comprises a hexagonal upper sand box (203) and a hexagonal lower sand box (204) of identical structure and interlockable, wherein the hexagonal upper sand box (203) and the hexagonal lower sand box (204) are locked by cooperating with bolts and nuts through a plurality of uniform positioning grooves (213) at the edge of the opening, and the hexagonal upper sand box (203) and the hexagonal lower sand box (204) are positioned by cooperating with positioning pins (207) and positioning pin sleeves (206) through any pair of symmetrical sides at the opening, and an upper triangular fixing arm (201) and a lower triangular fixing arm (205) are respectively arranged at the top of the hexagonal upper sand box (203) and the bottom of the hexagonal lower sand box (204), and the upper triangular fixing arm (201) and the lower triangular fixing arm (205) are respectively connected together by three triangular arm connecting plates (202).

3. The special sand box for casting wind turbine hub according to claim 2, characterized in that: The side of the hexagonal upper sand box (203) is a hollow structure composed of a sand box outer plate (215), a sand box inner plate (217) and two upper and lower connecting plates (209). The sand box outer plate (215) and the sand box inner plate (217) are connected together by welding through a plurality of support rods (216). A sand box belt (211) is arranged at the bottom of the hexagonal upper sand box (203). The outer side of the sand box outer plate (215) is arranged with reinforcing ribs (214) arranged in a horizontal and vertical manner. The six faces of the sand box outer plate (215) are each arranged with two lifting and flipping ears (208). The six faces of the sand box outer plate (215) other than the positioning seat (210) are each arranged with a negative pressure exhaust connection pipe joint (212) that passes through the sand box outer plate (215) and the sand box inner plate (217) in sequence.

4. The special sand box for casting wind turbine hub according to claim 3, characterized in that: The inner side of the sand box outer plate (215) is provided with a plurality of positioning support rod positioning blind holes (2151) for positioning the large diameter end of the support rod (216), and the side of the sand box inner plate (217) is provided with a plurality of positioning support rod positioning through holes (2171) for positioning the small diameter end of the support rod (216).

5. The special sand box for casting wind turbine hub according to claim 4, characterized in that: The pouring cup system (100) comprises a pouring cup sand box (101), the inner side of the pouring cup sand box (101) is arranged with refractory bricks (102), the outer side of the pouring cup sand box (101) is respectively provided with a hook support (109) and a fixed support (106), the hook support (109) and the fixed support (106) are successively penetrated with a guide shaft (107) parallel to the side of the pouring cup sand box (101), the end of the hook support (109) is hinged to the middle part of the lever handle (108), and one end of the lever handle (108) is hinged to the hook support The guide shaft (107) between the seat (109) and the fixed support (106) is hinged at the side, the end of the guide shaft (107) close to the fixed support (106) is vertically connected to one end of the upper support rod (105), the other end of the upper support rod (105) is vertically connected to one end of the stopper rod (104), a sleeve brick (103) is sleeved on the stopper rod (104), and a pouring hole (110) connected to one end of the pouring pipe (401) is provided at the bottom of the pouring cup sand box (101), and the end of the sleeve brick (103) can be matched with the pouring hole (110).

6. The special sand box for casting wind turbine hub according to claim 5, characterized in that: The hub mold (300) comprises an upper hub mold (303) and a lower hub mold (305) which are interlocked and have air holes, the main shaft mounting surface of the upper hub mold (303) being evenly arranged with at least 6 air-permeable risers (301) and a plurality of first cold iron blocks (302), the main shaft mounting surface of the lower hub mold (305) being evenly arranged with a plurality of casting connecting columns (307), the outer sides and inner sides of the three variable pitch bearing mounting surfaces formed by the upper hub mold (303) and the lower hub mold (305) being evenly arranged with a plurality of second cold iron blocks (304), and the main shaft mounting surface of the lower hub mold (305) being evenly arranged with a plurality of third cold iron blocks (306).

7. The special sand box for casting wind turbine hub according to claim 6, characterized in that: The pouring system (400) comprises a pouring accommodating shell (404) arranged in an inner hole of the main shaft mounting surface of the lower hub mold (305); a distribution plate (402) is buckled on the top of the pouring accommodating shell (404); the distribution plate (402) is connected to one end of a plurality of distribution pipes (403) through a plurality of connection holes evenly arranged; the other ends of the plurality of distribution pipes (403) are connected to a plurality of pouring connecting columns (307); a middle hole is provided in the middle of the distribution plate (402) and is connected to the other end of the pouring pipe (401); the pouring pipe (401) is connected to the plurality of distribution pipes (403) respectively through the cavity formed by the pouring accommodating shell (404) and the distribution plate (402).

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