Motor housing casting core assembly and casting process for facilitating exhaust

Abstract

The application discloses a low-pressure group core casting mold and casting process of a motor shell casting facilitating exhaust, relates to the casting processing technology field, and solves the problem of sand core exhaust in the casting process of the casting. The application comprises a bottom plate core, a runner core, a cylinder core, a water jacket core, a plurality of side cores, a top contour core, a riser core and a top cover core, the bottom plate core is provided with the runner core, the runner core is provided with the cylinder core, the water jacket core and the plurality of side cores, the side cores are provided with the top contour core, the cylinder core is provided with the riser core, and the riser core is embedded in the top contour core; the top contour core and the riser core are provided with the top cover core on the upper surfaces, the top cover core is provided with an exhaust plug, the cylinder core and the riser core are provided with hollow structures and a plurality of exhaust grooves, the hollow structures and the plurality of exhaust grooves are communicated, and the generated gas is exhausted. The application realizes the exhaust of the gas in the cavity through the cooperation between the exhaust grooves between the sand cores and the exhaust plug, the mesh number type sand with better exhaust effect can be used due to no additional pressurization, and the exhaust effect is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of casting processing, and particularly relates to a motor shell casting low-pressure group core casting mold facilitating exhaust and a casting process. BACKGROUND

[0002] At present, traditional low-pressure group core casting (also referred to as "low-pressure sand mold casting") is commonly used for producing aluminum alloy shell castings such as motor shells. The process is to push the aluminum alloy liquid in the furnace into the casting cavity formed by the sand core assembly through the ceramic liquid lifting pipe in the holding furnace by compressed air. After the filling is completed, the aluminum alloy liquid in the cavity is cooled and solidified under pressure by increasing the pressure until the final casting is formed.

[0003] Bubble defects are a common product defect form of aluminum alloy castings, which are mainly caused by the following reasons: during the filling and solidification of the aluminum alloy liquid, the resin curing agent in the sand core will generate and release gas from the sand core (i.e., the sand core generates gas), and these gases will often float to the riser or be discharged from the cavity. If these gases remain in the form of bubbles in the casting cavity, the casting will produce bubble defects, resulting in the casting being scrapped. This defect is more common in thin-walled aluminum alloy castings such as motor shells, especially in core-making processes with high resin addition.

[0004] At present, the existing group core low-pressure casting process adopts a pressure increase of 50-180 mbar during solidification, which can eliminate the shrinkage and porosity at the casting gate position by pressure effect, and also promote the discharge of sand core gas generation. Due to the need for pressure increase during solidification, a fully enclosed cavity is required, but the exhaust capacity of the sand core itself and the sand core joint is very limited, which cannot effectively exhaust the cavity, resulting in bubble defects in the casting and a certain amount of waste products. At the same time, due to the pressure increase, in order to avoid sand sticking to the sand core, a sand material with a mesh size of 70-140 or higher must be used, or a low-mesh sand material must be used and a sand sticking prevention coating must be applied to the surface of the sand core, which further limits the exhaust effect of the sand core itself and the exhaust effect of the cavity. SUMMARY

[0005] In order to solve the problem of sand core exhaust in the casting process mentioned above, the application provides a motor shell casting low-pressure group core casting mold facilitating exhaust and a casting process. The application is different from the traditional low-pressure casting, which abandons the technical route of eliminating gas holes by pressure increase during solidification, and instead uses a non-extra pressure increase method, and cooperates with the process design of the exhaust passage between the sand cores and the exhaust plug at the top of the mold to realize the exhaust of the gas in the cavity. Due to the non-extra pressure increase, the use of mesh size sand with better self-exhaust effect becomes possible, further improving the exhaust effect of the cavity.

[0006] The application provides a low-pressure group core casting mold for a motor shell casting facilitating exhaust, which specifically comprises a bottom plate core, a sprue core, a cylinder core, a water jacket core, a plurality of side cores, a top contour core, a riser core and a top cover core, the bottom plate core is provided with the sprue core, the sprue core is provided with the cylinder core, the water jacket core and the plurality of side cores, the cylinder core is provided with the water jacket core, and the water jacket core is provided with the plurality of side cores, the plurality of side cores are provided with the top contour core, the cylinder core is provided with the riser core, and the riser core is embedded in the top contour core, the top contour core and the riser core are provided with the top cover core on the upper surfaces, the cylinder core and the riser core are provided with hollow structures in the interiors, the cylinder core is further provided with a plurality of exhaust grooves one, and the riser core is further provided with exhaust grooves two, and the hollow structures are communicated with the exhaust grooves one and the exhaust grooves two respectively to exhaust the gas generated in the casting process.

[0007] Further, the exhaust grooves one have a depth of 0.15mm-0.2mm and a width of 3mm-5mm.

[0008] Further, the exhaust grooves two are Z-shaped, have a depth of 0.4mm-0.85mm and a width of 5mm-8mm.

[0009] Further, the riser core is further provided with a riser cavity, and the riser cavity is communicated with the hollow structure through the exhaust grooves two.

[0010] Further, the cylinder core is provided with a bearing bush at the bottom center, and the bearing bush is cast together with the casting in the casting process.

[0011] Further, the bearing bush is provided with a plurality of vertical exhaust grooves, and the vertical exhaust grooves have a depth of 2mm-3mm and a width of ≥1.5mm.

[0012] Further, the top cover core is provided with an exhaust plug and an exhaust hole, the exhaust plug is arranged in the exhaust hole, and the exhaust hole is communicated with the hollow structure.

[0013] Further, the bottom plate core is provided with a gate, and the gate is provided with a filter piece.

[0014] Further, the water jacket core is provided with a plurality of water jacket core heads, the water jacket core heads are circumferentially positioned on the water jacket core in cooperation with the side cores, and the cooperation surfaces are provided with a gap of 0.3±0.05mm.

[0015] A casting process using the low-pressure group core casting mold for the motor shell casting facilitating exhaust, which specifically comprises the following steps:

[0016] a. The filter piece is arranged on the bottom plate core, the sprue core is arranged on the upper end of the bottom plate core 1, then the cylinder core, the water jacket core and the plurality of side cores are arranged on the sprue core in sequence, the top contour core is arranged on the plurality of side cores, the riser core is embedded in the top contour core, and the top cover core 9 is arranged on the top contour core and the riser core.

[0017] b. The mold is placed and fixed on the holding furnace of the low-pressure casting equipment, and the bottom gate of the mold is connected with the top end of the riser tube in the furnace of the casting machine;

[0018] c. During the casting process, the aluminum alloy liquid is pushed by the compressed air of the low-pressure casting machine, and is pushed into the mold through the holding furnace and the riser tube and is continuously pressure-kept; the pressure curve is set in the filling stage, so that the liquid surface finally stays at a position 15mm-25mm away from the top of the riser cavity; the pressure is maintained in the solidification pressure-keeping stage, so that the liquid surface always stays at the position, and the casting of the casting is completed.

[0019] The low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust have the beneficial effects that:

[0020] (1) The low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust change the casting mode of the traditional casting process which needs additional pressure to eliminate pores, and realize the exhaust of the gas in the cavity through the cooperation of the process design of the exhaust passages between the sand cores and the exhaust plugs on the top of the sand packs;

[0021] (2) The low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust communicate the mold cavity and the hollow structure inside through the exhaust groove one arranged on the cylindrical core and the exhaust groove two arranged on the riser core, so that the gas generated in the casting process is exhausted to the outside of the mold;

[0022] (3) The low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust guides the gas generated in the casting process of the casting to the edge of the cavity through the vertical exhaust grooves arranged on the outer side of the bearing bush, so as to prevent the gas from accumulating in the casting and reduce the product scrap rate. BRIEF DESCRIPTION OF DRAWINGS

[0023] The drawings constituting a part of this application are used to provide further understanding of the present application, the schematic embodiments of the present application and the description thereof are used to explain the present application, and do not constitute improper limitation on the present application.

[0024] In the drawings:

[0025] Figure 1 is the mold structure explosion view of the low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust according to the present application;

[0026] Figure 2 is the mold structure perspective view of the low-pressure group core casting mold and casting process for the motor shell casting convenient for exhaust according to the present application;

[0027] Figure 3is a low-pressure core casting mold and casting process of a motor shell casting with convenient exhaust of the present application;

[0028] Figure 4 is a low-pressure core casting mold and casting process of a motor shell casting with convenient exhaust of the present application;

[0029] Wherein: 1 - bottom plate core, 2 - filter sheet, 3 - runner core, 4 - cylinder core, 5 - water jacket core, 6 - side core, 7 - top contour core, 8 - riser core, 9 - top cover core, 10 - bearing bushing, 11 - exhaust plug, 12 - vertical exhaust groove, 13 - hollow structure, 14 - exhaust hole, 15 - exhaust groove one, 16 - exhaust groove two, 17 - riser cavity, 18 - water jacket core head, 19 - riser core top surface. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are further described in detail below with reference to the accompanying drawings:

[0031] Specific embodiment one: see Figures 1-4 Specifically, the low-pressure core casting mold of a motor shell casting with convenient exhaust described in this embodiment is a sand package formed by a plurality of sand cores, which specifically includes a bottom plate core 1, a runner core 3, a cylinder core 4, a water jacket core 5, a plurality of side cores 6, a top contour core 7, a riser core 8 and a top cover core 9, the bottom plate core 1 is installed with the runner core 3; the runner core 3 is installed with the cylinder core 4, the water jacket core 5 and the plurality of side cores 6, the cylinder core 4 is installed with the water jacket core 5 outside, and the water jacket core 5 is installed with the plurality of side cores 6 outside; the upper surface of the runner core 3 is provided with a plurality of insertion slots, the upper and lower ends of the side core 6 are provided with insertion blocks, and the side core 6 is installed by inserting the lower end insertion block into the insertion slot on the runner core 3;

[0032] The plurality of side cores 6 are installed with the top contour core 7, the lower surface of the top contour core 7 is provided with a plurality of insertion slots, and the top contour core 7 is installed by cooperating with the insertion blocks on the upper end of the side core 6 through the insertion slots on the lower surface of the top contour core 7; the cylinder core 4 is installed with the riser core 8, and the riser core 8 is embedded into the top contour core 7; the top contour core 7 and the riser core 8 are installed with the top cover core 9 on the upper surface;

[0033] The cylinder core 4 and the riser core 8 are provided with a hollow structure 13 inside, the cylinder core 4 is further provided with a plurality of exhaust grooves one 15, the exhaust grooves one 15 are located on the abutting surface of the cylinder core 4 and the riser core 8; the riser core 8 is further provided with exhaust grooves two 16, the exhaust grooves two 16 are located on the riser core top surface 19 on the riser core 8; the hollow structure 13 is in communication with the exhaust grooves one 15 and the exhaust grooves two 16 respectively, and the gas generated by the sand core during the casting process is discharged to the outside of the mold.

[0034] The depth of the exhaust groove 15 is 0.15mm-0.2mm, and the width is 3mm-5mm.

[0035] The exhaust groove 16 is Z-shaped, with a depth of 0.4mm-0.85mm and a width of 5mm-8mm; the riser core 8 is further provided with a riser cavity 17, which is communicated with the hollow structure 13 through the exhaust groove 16; the exhaust groove 16 is designed in Z shape to ensure the smooth exhaust of gas during the casting of the motor shell, and to prevent the aluminum alloy liquid from flowing into the hollow structure 13 from the exhaust groove 16 by lengthening the total length of the exhaust groove 16.

[0036] The bottom center of the cylindrical core 4 is provided with a bearing bush 10, which is cast together with the casting during the casting process; the bearing bush 10 is provided with a plurality of vertical exhaust grooves 12, which guide the gas generated by the sand core during the casting process to the edge of the mold cavity, preventing the gas generated by the sand core during the casting process from accumulating inside the casting to form pores; the depth of the vertical exhaust groove 12 is 2mm-3mm, and the width is ≥1.5mm.

[0037] The top cover core 9 is provided with an exhaust plug 11 and an exhaust hole 14, and the exhaust plug 11 is arranged in the exhaust hole 14; the exhaust plug 11 is arranged to avoid the fire running on the top of the mold due to improper pressure curve setting during pouring.

[0038] The hollow structure 13 is communicated with the exhaust hole 14 to exhaust the gas generated during the casting of the casting from the inside of the mold to the outside of the mold.

[0039] The bottom plate core 1 is provided with a sprue, and the inside of the sprue is provided with a filter 2 to filter the aluminum alloy liquid entering the inside of the mold.

[0040] The water jacket core 5 is provided with a plurality of water jacket core heads 18, which are used in cooperation with the side core 6 to position the circumferential position of the water jacket core 5; the cooperation surface of the water jacket core head 18 and the side core 6 is provided with a gap of 0.3±0.05mm.

[0041] In order to improve the air permeability of the sand core itself, all the sand cores use raw sand with a mesh number of 50-100.

[0042] A casting process using the above-mentioned low-pressure group core casting mold for the motor shell casting is provided, which specifically includes the following steps:

[0043] a. Install the filter sheet 2 on the bottom plate core 1, place the runner core 3 on the upper end of the bottom plate core 1, and then place the cylindrical core 4, the water jacket core 5 and the plurality of side cores 6 on the runner core 3 in sequence; place the top contour core 7 on the plurality of side cores 6, embed the riser core 8 into the top contour core 7, and place the top cover core 9 on the top contour core 7 and the riser core 8 to complete the mold assembly;

[0044] b. Place and fix the mold on the holding furnace of the low-pressure pouring equipment, and butt joint the top end of the riser pipe in the furnace of the pouring machine with the bottom gate of the mold;

[0045] c. During the pouring process, the aluminum alloy liquid is pushed by the compressed air of the low-pressure pouring machine, and is pushed into the mold through the holding furnace and the riser pipe and is continuously pressure-kept; the pressure curve is set in the filling stage to make the liquid surface finally stay at a position 15mm-25mm away from the top of the riser cavity 17; the pressure is maintained in the solidification pressure-keeping stage to make the liquid surface always stay at the position, and the casting is completed.

[0046] During the casting process of the casting, the pressure increasing speed in the riser and filling stages and the pressure releasing time at the end of solidification have no special requirements.

[0047] Summarizing the above implementation cases, the low-pressure core assembly casting mold and casting process of the motor shell casting convenient for exhaust change the casting mode of the traditional casting process which needs additional pressure to eliminate pores, and realize the exhaust of the gas in the cavity by the cooperation of the process design of the exhaust passages between the sand cores and the exhaust plugs on the top of the sand packs.

[0048] The low-pressure core assembly casting mold and casting process of the motor shell casting convenient for exhaust disclosed by the application communicate the mold cavity and the hollow structure inside by the exhaust groove one 15 arranged on the cylindrical core 4 and the exhaust groove two 16 arranged on the riser core 8, so that the gas generated in the casting process is exhausted to the outside of the mold; the low-pressure core assembly casting mold and casting process of the motor shell casting convenient for exhaust disclosed by the application guide the gas generated in the casting process of the casting to the edge of the cavity by arranging a plurality of vertical exhaust grooves 12 on the outside of the bearing bush 10, so as to prevent the gas from accumulating in the casting and reduce the product rejection rate.

[0049] The above specific embodiments further specifically describe the purpose, technical scheme and beneficial effects of the application. It should be understood that the above description is only for specific embodiments of the application and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A low pressure group core casting mold for a motor housing casting with venting facilitation, characterized by: It includes bottom plate core (1), sprue core (3), cylinder core (4), water jacket core (5), several side cores (6), top profile core (7), riser core (8) and top cover core (9), the bottom plate core (1) is installed with sprue core (3); the sprue core (3) is installed with cylinder core (4), water jacket core (5) and several side cores (6), the cylinder core (4) is installed with water jacket core (5) outside, and the water jacket core (5) is installed with several side cores (6) outside; several side cores (6) are installed with top profile core (7), the cylinder core (4) is installed with riser core (8), and the riser core (8) is embedded into top profile core (7); the top profile core (7) and riser core (8) are installed with top cover core (9) on the upper surface; The cylinder core (4) and riser core (8) are provided with hollow structure (13) inside, and the cylinder core (4) is further provided with several exhaust grooves one (15), and the riser core (8) is further provided with several exhaust grooves two (16); the hollow structure (13) is communicated with the exhaust grooves one (15) and the exhaust grooves two (16) respectively, and the gas generated in the casting process is discharged; The bottom center of the cylinder core (4) is installed with bearing bushing (10), and the bearing bushing (10) is cast together with the casting during the casting process; the bearing bushing (10) is provided with several vertical exhaust grooves (12), and the depth of the vertical exhaust grooves (12) is 2mm-3mm, and the width is greater than or equal to 1.5mm.

2. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, wherein: The depth of the exhaust grooves one (15) is 0.15mm-0.2mm, and the width is 3mm-5mm.

3. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, wherein: The exhaust grooves two (16) are Z-shaped, the depth is 0.4mm-0.85mm, and the width is 5mm-8mm.

4. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, 2, or 3, characterized in that: The riser core (8) is further provided with riser cavity (17), and the riser cavity (17) is communicated with the hollow structure (13) through the exhaust grooves two (16).

5. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, 2, or 3, wherein: The top cover core (9) is provided with exhaust plug (11) and exhaust hole (14), the exhaust plug (11) is arranged in the exhaust hole (14), and the exhaust hole (14) is communicated with the hollow structure (13).

6. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, 2, or 3, wherein: The bottom plate core (1) is provided with a sprue, and the inside of the sprue is provided with a filter piece (2).

7. The vent facilitated motor housing casting low pressure group core casting mold of claim 1, 2, or 3, wherein: The water jacket core (5) is provided with several water jacket core heads (18), and the water jacket core heads (18) are used for positioning the water jacket core (5) in the circumferential direction in cooperation with the side cores (6), and the gap between the cooperation surfaces is 0.3±0.05mm.

8. A casting process using the low pressure core casting mold for the venting facilitated motor housing casting of claim 6, characterized by: It includes the following steps: a. install the filter piece (2) on the bottom plate core (1), place the sprue core (3) on the upper end of the bottom plate core (1), and then place the cylinder core (4), the water jacket core (5) and the several side cores (6) on the sprue core (3) in sequence; place the top profile core (7) on the several side cores (6), embed the riser core (8) into the top profile core (7), and place the top cover core (9) on the top profile core (7) and the riser core (8); b. place and fix the mold on the holding furnace of the low-pressure pouring equipment, and the bottom sprue of the mold is connected with the top end of the liquid lifting pipe in the pouring machine furnace. c. During pouring, the aluminum alloy liquid is pushed by compressed air of the low-pressure pouring machine, and is pushed into the mold through the holding furnace and the liquid lifting pipe and is continuously kept at pressure. A pressure curve is set in the filling stage to make the liquid surface finally stay at a position 15mm-25mm away from the top of the riser cavity (17). The pressure is maintained in the solidification and pressure keeping stage to make the liquid surface always stay at this position. The casting of the casting is completed.

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