A casting mold for a ductile iron gear hub

Abstract

The application discloses a nodular cast iron gear hub casting mold, which comprises a lower mold, an upper mold and a core box mold, the lower mold comprises a lower mold plate, a lower sand box, a gear hub casting, a gear hub riser, an inner gate, a straight gate pocket and a lower sand mold cross gate, the upper mold comprises an upper mold plate, an upper sand box, an upper sand mold cross gate, a straight gate top structure and a straight gate, the core box mold comprises a core box bottom plate, a left half mold core box and a right half mold core box, positioning pins for positioning the sand boxes are arranged at the middle positions of the two ends of the upper mold plate and the lower mold plate, the upper sand box and the lower sand box are integral casting sand boxes, the lower mold further comprises a lower sand mold lap joint structure and a filter piece mold, the filter piece mold is arranged at the opposite position of the lower sand mold lap joint structure, and the nodular cast iron gear hub casting mold can reduce the inclusion, porosity and loose defects of the gear hub, improve the internal quality of the gear hub and reduce the casting defects of the gear hub.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gear hub casting, in particular to a casting mold for nodular cast iron gear hub. BACKGROUND

[0002] Gear hub is an important part of transmission machinery parts, the material used is nodular cast iron, and the internal organization is required to be dense during use, and defects such as shrinkage, shrinkage hole, slag inclusion and porosity cannot appear.

[0003] And the existing gear hub casting mold has the following defects: (1) the cold iron is difficult to place during the core making process, and it is not easy to operate, the cold iron does not directly contact with the casting, and the chilling effect of the thick hub is weak, and there is a risk that the internal casting defects of the hub during casting cannot be effectively eliminated; (2) the gating system has no slag filtering structure, and the designed horizontal runner and other gating systems cannot effectively filter the slag in the metal liquid, which is easy to cause the casting to have slag inclusion defects; (3) there is no air hole similar to the exhaust structure in the structure, and the exhaust is not smooth during pouring, which is easy to cause the casting to have defects such as insufficient pouring and porosity; (4) there is no sand core exhaust structure, most of the sand core is wrapped by the iron liquid during pouring, and a large amount of gas will be generated in the sand core under the action of high temperature, and when there is no exhaust structure, the casting is easy to have porosity defects. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the existing defects, provide a casting mold for nodular cast iron gear hub, which can reduce the inclusion, porosity and porosity defects of the gear hub, improve the internal quality, reduce the casting defects of the gear hub, and effectively solve the problems in the background art.

[0005] In order to achieve the above object, the present application provides the following technical scheme: A casting mold for a nodular cast iron gear hub, comprising a lower mold, an upper mold and a core box mold, the lower mold comprising a lower mold plate, a lower sand box, a gear hub casting, a gear hub riser, an inner gate, a straight gate pocket and a lower sand mold cross gate, the upper mold comprising an upper mold plate, an upper sand box, an upper sand mold cross gate, a straight gate top structure and a straight gate, the core box mold comprising a core box bottom plate, a left half mold core box and a right half mold core box, the upper mold plate and the lower mold plate having positioning pins for positioning the sand box at the middle position of both ends, the upper sand box and the lower sand box being integral casting sand boxes, the lower mold further comprising a lower sand mold lap joint structure and a filter plate mold, the filter plate mold being arranged at the opposite position of the lower sand mold lap joint structure, the gear hub casting having four annular chill placement areas uniformly distributed around the bottom of the gear hub casting, the annular chill placement areas being provided with chills, the upper mold plate further comprising an air outlet hole, an upper sand mold lap joint structure and an upper mold air outlet hole, the air outlet hole and the upper mold air outlet hole being arranged on the upper mold plate, the upper sand mold lap joint structure and the lower sand mold lap joint structure being in complementary relationship in shape, and the cross-sectional dimensions of the upper sand mold lap joint structure and the lower sand mold lap joint structure being greater than the cross-sectional dimensions of the lower sand mold cross gate and the upper sand mold cross gate respectively, the left half mold core box and the right half mold core box having core box chill placement areas for placing chills around the inner sides, and the left half mold core box and the right half mold core box being respectively provided with sand core air outlet hole molds.

[0006] As a preferred technical scheme of the present application, the center of the gear hub casting is located on the center line of the length direction of the lower mold plate and the center line of the gear hub mold, and is located at 35-45 mm on one side of the center line of the width direction of the lower mold plate.

[0007] As a preferred technical scheme of the present application, the gear hub riser is in an integral structure with the gear hub casting, and the gear hub riser extends in the direction of the gear hub casting to form a Y shape, the slope of the gear hub riser is 3-6°, and the height of the gear hub riser is one third of the height of the gear hub casting.

[0008] As a preferred technical scheme of the present application, the inner gates are arranged in a ring shape around the center position of the gear hub casting and are four in number, and the cross section of the inner gate is trapezoidal.

[0009] As a preferred technical scheme of the present application, the straight gate top structure is funnel-shaped.

[0010] As a preferred technical scheme of the present application, the air outlet hole, the upper mold air outlet hole and the straight gate are all detachable structures.

[0011] As a preferred technical scheme of the present application, the upper sand mold cross gate and the upper sand mold lap joint structure are fixed on the upper mold plate by bolts.

[0012] As a preferred embodiment of the present invention, the center lines of the lower mold plate in the width direction and the upper mold plate in the width direction, as well as the center lines of the lower mold plate in the length direction and the upper mold plate in the length direction, are aligned. The center lines of the gear hub mold and the upper sand mold are symmetrically distributed relative to the center lines of the lower mold plate in the width direction and the upper mold plate in the width direction.

[0013] As a preferred embodiment of the present invention, the left half core box and the right half core box are fixedly connected by screws, washers and nuts. The left half core box and the right half core box are respectively equipped with sand core venting hole mold fixing structures for positioning the sand core venting hole mold.

[0014] As a preferred embodiment of the present invention, both the annular chill placement area and the core box chill placement area are inlaid with devices for adsorbing chills.

[0015] Compared with the prior art, the beneficial effects of the present invention are: (1) An annular chill is placed in the annular chill placement area at the bottom of the gear hub casting. The annular chill is evenly distributed within a 360° range at the bottom, which can effectively cool the gear hub after pouring. When used in conjunction with the gear hub riser, it realizes the sequential solidification method of the gear hub from bottom to top, ensuring the internal quality of the gear hub; (2) Chips are placed in an annular arrangement within a 360° range on the circumference of the chill placement area of ​​the core box in the inner cavity of the gear hub core box mold. The chills are directly attached to the inner wall of the gear hub cavity, ensuring the internal quality of the gear hub cavity tooth profile and avoiding casting defects such as shrinkage porosity and shrinkage holes at the tooth profile position; (3) Using The sand core venting hole mold forms a sand core venting hole at the center of the sand core. Its structure is a hollow structure. In the upper mold, the upper mold venting hole is used to form a hollow venting hole in the upper sand mold. This venting hole is connected to the sand core venting hole, which ensures that the gas generated by the resin and curing agent in the sand core under high temperature during the iron pouring process can be smoothly discharged to the outside, avoiding gas intrusion into the iron and causing porosity defects in the gear hub; (4) After the gear hub is assembled, dry sand is filled into the hollow structure of the sand core to prevent the iron from entering the sand core venting hole during the pouring process, thus avoiding the gas generated by the sand core from not being able to be discharged smoothly and causing porosity defects in the gear hub. It also avoids wasting iron and thus saves production energy consumption. Attached Figure Description

[0016] Figure 1 This is a top view of the lower mold of the present invention;

[0017] Figure 2 for Figure 1 Sectional view at point AA;

[0018] Figure 3 This is a top view of the upper mold of the present invention;

[0019] Figure 4 forFigure 3 Sectional view at point BB;

[0020] Figure 5 This is a top view of the core box mold of the present invention;

[0021] Figure 6 for Figure 5 Schematic diagram at point C;

[0022] Figure 7 for Figure 5 Sectional view at point DD.

[0023] In the diagram: 1. Centerline of the lower mold plate in the width direction; 2. Centerline of the gear hub mold; 3. Centerline of the lower mold plate in the length direction; 4. Sprue recess; 5. Lower sand mold runner; 6. Lower sand mold overlap structure; 7. Filter plate mold; 8. Ingate; 9. Locating pin; 10. Annular chill placement area; 11. Lower mold plate; 12. Lower sand box; 13. Gear hub riser; 14. Gear hub casting; 15. Upper mold vent hole; 16. Vent hole; 17. Centerline of the upper mold plate in the length direction. 18 Upper mold plate width direction centerline, 19 Upper sand mold centerline, 20 Upper sand mold horizontal runner, 21 Upper sand mold overlapping structure, 22 Upper mold plate, 23 Upper sand box, 24 Top structure of sprue, 25 Sprue, 26 Sand core vent hole mold fixing structure, 27 Sand core vent hole mold, 28 Screw, 29 Nut, 30 Washer, 31 Core box bottom plate, 32 Left half of core box, 33 Core box chill placement area, 34 Right half of core box. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments (for ease of description and understanding, the following refers to...). Figure 2 (The above is described above). Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0025] Please see Figures 1-7 The present invention provides a technical solution: a casting mold for a ductile iron gear hub, comprising a lower mold, an upper mold and a core box mold;

[0026] The lower mold includes a lower mold plate 11, a lower sand box 12, a gear hub casting 14, a gear hub riser 13, an ingate 8, a sprue recess 4, a lower sand mold runner 5, a lower sand mold overlapping structure 6, and a filter plate mold 7. The filter plate mold 7 is set at a relative position to the lower sand mold overlapping structure 6. Four annular chill placement areas 10 are evenly distributed around the bottom of the gear hub casting 14. Chills are placed in the annular chill placement areas 10. The center of the gear hub casting 14 is located on the center line 3 of the length direction of the lower mold plate and the center line 2 of the gear hub mold, and is located 35-45mm away from the center line 1 of the width direction of the lower mold plate.

[0027] The gear hub riser 13 and the gear hub casting 14 are an integral structure, and the gear hub riser 13 extends in a Y shape along the direction of the gear hub casting 14. The slope of the gear hub riser 13 is 3 to 6 degrees, and the height is one-third of the height of the gear hub casting 14, which can ensure that the molten iron forms a uniform feeding effect on the entire gear hub.

[0028] A filter plate mold is designed at the corresponding position of the lower sand mold lap structure 6 to effectively filter impurities in the molten iron and prevent impurity defects in the gear hub caused by the impurity of the molten iron.

[0029] The ingate 8 is arranged in a ring with four evenly spaced sections around the center of the gear hub casting 14. The cross-section of the ingate 8 is trapezoidal, which makes the molten iron filling more stable, avoids local heat concentration, and reduces its impact on the casting.

[0030] Four annular chill placement areas 10 are evenly distributed within a 360° range at the bottom of the gear hub casting 14. The gap between each annular chill placement area 10 is 20-30mm. In this invention, the gap between the annular chills is 22mm. The gap is filled with molding sand during the production of the sand mold, which can effectively cool the gear hub after casting. When used in conjunction with the riser, it realizes the sequential solidification method of the gear hub from bottom to top, ensuring the internal quality of the gear hub.

[0031] The upper mold includes an upper mold plate 22, an upper sand box 23, an upper sand mold horizontal runner 20, a sprue top structure 24 and a sprue 25, an vent 16, an upper sand mold overlapping structure 21 and an upper mold vent 15. The upper mold plate 22 and the lower mold plate 11 have positioning pins 9 at the middle of both ends for positioning the sand box. The upper sand box 23 and the lower sand box 12 are integrally cast sand boxes, which can effectively prevent the box from expanding during the pouring and cooling process and improve the internal density of the casting. The vent 16 and the upper mold vent 15 are both set on the upper mold plate 22. The upper sand mold overlapping structure 21 and the lower sand mold overlapping structure 6 are complementary in shape, and the cross-sectional dimensions of the upper sand mold overlapping structure 21 and the lower sand mold overlapping structure 6 are larger than the cross-sectional dimensions of the lower sand mold horizontal runner 5 and the upper sand mold horizontal runner 20, respectively. The upper sand mold horizontal runner 20 and the upper sand mold overlapping structure 21 are fixed to the upper mold plate 22 by bolts.

[0032] The cross-sectional dimensions of the upper sand mold overlapping structure 21 and the lower sand mold overlapping structure 6 are more than twice the cross-sectional dimensions of the lower sand mold horizontal runner 5 and the upper sand mold horizontal runner 20, respectively, to ensure that the flow rate of the molten iron does not affect the subsequent pouring system after passing through the filter plate mold 7.

[0033] The top structure 24 of the direct sprue is funnel-shaped, eliminating the need for a pouring cup during use, which facilitates accurate injection of molten iron during the pouring process and reduces molten iron spillage.

[0034] To facilitate the installation and disassembly of this mold, the vent 16, the upper vent 15, and the sprue 25 are all detachable structures.

[0035] To ensure the precise fit between the upper sand box 23 and the lower sand box 12, the center line 1 in the width direction of the lower mold plate and the center line 18 in the width direction of the upper mold plate, as well as the center line 3 in the length direction of the lower mold plate and the center line 17 in the length direction of the upper mold plate, are aligned. The center line 2 of the gear hub mold and the center line 19 of the upper sand mold are symmetrically distributed relative to the center line 1 in the width direction of the lower mold plate and the center line 18 in the width direction of the upper mold plate.

[0036] The core box mold includes a core box base plate 31, a left half core box 32, and a right half core box 34. The inner circumference of the left half core box 32 and the right half core box 34 is provided with a core box chill placement area 33 for placing chills. The left half core box 32 and the right half core box 34 are each provided with a sand core venting hole mold 27. The half core box 32 and the right half core box 34 are fixedly connected by a screw 28, a washer 30, and a nut 29. The left half core box 32 and the right half core box 34 each have a sand core venting hole mold. The fixed structure 26 is used to position the sand core venting hole mold 27. The sand core venting hole mold 27 is used to form a sand core venting hole at the center of the sand core. Its structure is hollow. In the upper mold, the upper mold venting hole 15 is used to form a hollow venting hole in the upper sand mold. This venting hole is connected to the sand core venting hole, which ensures that the gas generated by the resin and curing agent in the sand core under high temperature during the iron pouring process can be smoothly discharged to the outside, avoiding gas from entering the iron and causing porosity defects in the gear hub.

[0037] The core box chills are evenly distributed in a ring within a 360° range in the chill placement area 33. The chills are directly attached to the inner wall of the gear hub cavity, which ensures the internal quality of the gear hub cavity tooth profile and avoids casting defects such as shrinkage porosity and shrinkage holes at the tooth profile position.

[0038] To prevent the chills from moving during the casting process, devices for adsorbing the chills are embedded in both the annular chill placement area 10 and the core box chill placement area 33.

[0039] After the gear hub is assembled, dry sand is filled into the hollow structure of the sand core to prevent molten iron from entering the sand core vent during the casting process. This avoids the gas generated by the sand core from not being able to escape smoothly, which would cause porosity defects in the gear hub. It also avoids wasting molten iron and thus saves production energy.

[0040] Casting can be carried out by placing a pressure iron on top of the sand mold on the gear hub. Using the pressure iron instead of box clamps or bolts for fastening reduces the workload and labor intensity of the operator, and also prevents the box from being lifted and sparks from escaping during the casting process.

[0041] In addition, when casting gear hubs, placing one gear hub mold in the same mold can avoid the thermal influence between individual gear hubs during the pouring and cooling process, compared to placing multiple gear hub molds in one mold, thus reducing the internal defects of the gear hubs caused by this.

[0042] This invention can effectively filter impurities in molten iron, reduce impurities and porosity defects in gear hubs, and improve the internal quality of gear hubs. Experiments have shown that gear hubs produced using this invention have simple operation, stable product quality, and a high pass rate.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A casting mold for a ductile iron gear hub, comprising a lower mold, an upper mold, and a core box mold, wherein the lower mold comprises a lower mold plate (11), a lower sand box (12), a gear hub casting (14), a gear hub riser (13), an ingate (8), a sprue recess (4), and a lower sand mold runner (5); the upper mold comprises an upper mold plate (22), an upper sand box (23), an upper sand mold runner (20), a sprue top structure (24), and a sprue (25); the core box mold comprises a core box bottom plate (31), a left half core box (32), and a right half core box (34); and positioning pins (9) for positioning the sand box are located at the middle positions of both ends of the upper mold plate (22) and the lower mold plate (11), characterized in that: The upper sand box (23) and lower sand box (12) are integrally cast sand boxes. The lower mold also includes a lower sand mold overlapping structure (6) and a filter plate mold (7). The filter plate mold (7) is set at a relative position to the lower sand mold overlapping structure (6) and is fixed to the lower mold plate (11) by bolts. The bottom of the gear hub casting (14) has four annular chill placement areas (10) evenly distributed around it. Chills are placed in the annular chill placement areas (10). The upper mold plate (22) also includes an air vent (16), an upper sand mold overlapping structure (21), and an upper mold exhaust hole (15). Hole (16) and upper vent hole (15) are both set on upper mold plate (22). The shape of upper sand mold overlapping structure (21) and lower sand mold overlapping structure (6) are complementary. The cross-sectional dimensions of upper sand mold overlapping structure (21) and lower sand mold overlapping structure (6) are larger than the cross-sectional dimensions of lower sand mold horizontal runner (5) and upper sand mold horizontal runner (20), respectively. The inner side of the left half core box (32) and right half core box (34) is provided with a core box chill placement area (33) for placing chills. Sand core vent hole mold (27) is provided on the left half core box (32) and right half core box (34), respectively.

2. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The center of the gear hub casting (14) is located on the center line (3) of the length direction of the lower mold plate and the center line (2) of the gear hub mold, and is located 35-45mm away from the center line (1) of the width direction of the lower mold plate.

3. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The gear hub riser (13) and the gear hub casting (14) are an integral structure, and the gear hub riser (13) extends in a Y shape along the direction of the gear hub casting (14). The slope of the gear hub riser (13) is 3 to 6 degrees, and the height is one-third of the height of the gear hub casting (14).

4. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The ingate (8) is arranged in a ring of four evenly distributed along the center of the gear hub casting (14), and the cross section of the ingate (8) is trapezoidal.

5. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The top structure (24) of the direct pouring channel is funnel-shaped.

6. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The air outlet (16), the upper exhaust port (15), and the sprue (25) are all detachable structures.

7. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The upper sand mold horizontal sprue (20) and the upper sand mold overlapping structure (21) are fixed to the upper mold plate (22) by bolts.

8. The casting mold for a ductile iron gear hub according to claim 2, characterized in that: The center lines (1) of the lower mold plate in the width direction and (18) of the upper mold plate in the width direction, the center lines (3) of the lower mold plate in the length direction and (17) of the upper mold plate in the length direction coincide, and the center lines (2) of the gear hub mold and (19) of the upper sand mold are symmetrically distributed relative to the center lines (1) of the lower mold plate in the width direction and (18) of the upper mold plate in the width direction.

9. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: The left half core box (32) and the right half core box (34) are fixedly connected by screws (28), washers (30) and nuts (29). The left half core box (32) and the right half core box (34) are respectively equipped with sand core vent hole mold fixing structures (26) for positioning sand core vent hole molds (27).

10. The casting mold for a ductile iron gear hub according to claim 1, characterized in that: Both the annular chill placement area (10) and the core box chill placement area (33) are inlaid with devices for adsorbing chills.

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