Thin-wall tramcar gearbox body and casting process
By adopting optimized mold structure and special sand core materials in the casting process of tram gear box, the problem of uneven wall thickness of castings in the prior art is solved, higher strength and reliability are achieved, and reduced production costs.
Patent Information
- Application Number
- CN202411520780.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-02-14
AI Technical Summary
During the casting process, existing tram gearbox boxes are prone to problems such as cold partitions, insufficient pouring, and white mouths, resulting in uneven wall thickness of the box, affecting the strength and reliability of the gearbox.
Using metal mold and resin sand technology, by optimizing the mold structure, adding steel plates and designing inner gates of ceramic tubes, using chromite ore sand to make sand cores, and designing C-shaped inspection tools and sand core core heads to ensure the wall thickness of the castings and dimensional accuracy.
It significantly improves the casting quality of the gear box box, ensures uniformity of the wall thickness, enhances the strength and reliability of the gear box, reduces production costs, and avoids operating failures and safety accidents caused by fins and sand sticking.
Smart Images
Figure CN119426525A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of rail transit equipment, in particular to a thin-walled tram gearbox housing and a casting process. Background Art
[0002] Tram transmission gearbox housing (also called gearbox, traction gearbox, transmission gearbox) is mainly used in intercity rail transportation. Traction transmission gearbox is a key component of trams, responsible for transmitting the power of trams to wheelsets.
[0003] As a key component of the bogie, the performance of the traction drive gearbox directly affects the performance of the bogie. It can be said that the strength and reliability of the gearbox will directly affect the operating safety and service life of the tram. Therefore, in-depth research on the operating mechanism of the traction drive gearbox and improving its design and processing level are major issues facing the field of rail transit power systems.
[0004] 1. Through effective analysis of the wall thickness of the casting box, a scientific, efficient and stable pouring system is designed to solve the problems of thin wall thickness of the casting box, easy cold shut, insufficient pouring and white spots in the metallographic structure. The system can fill the box quickly during pouring, with small temperature drop, no air entrainment, no turbulence, uniform wall thickness of the casting box, small flash, dense material, excellent performance and beautiful appearance.
[0005] 2. During the sand core assembly process of the tram gearbox, the sand core is often not assembled properly, resulting in large changes in the sand core size.
[0006] To this end, the present invention provides a thin-walled tram gearbox housing and a casting process. Summary of the invention
[0007] 1. Technical issues to be resolved
[0008] In view of the deficiencies in the prior art, the present invention provides a thin-walled tram gearbox housing and a casting process. In the casting process, a metal mold and a resin sand process are adopted. By optimizing the mold structure, the service life of the mold is significantly improved, thereby improving the casting quality of the tram gearbox housing and solving the problems raised by the background technology.
[0009] (II) Technical solution
[0010] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a casting process for a thin-walled tram gearbox housing, the specific steps are as follows:
[0011] Step 1: Add steel plates to the casting mold and pad the steel plates on the sanded surface of the core box of the casting mold to solve the problems of poor wear resistance of the aluminum mold surface, frequent sanding, severe wear and large changes in sand core size;
[0012] Step 2: Design a gate in the ceramic tube, set a water inlet pipeline at the thin wall at the far end of the lower box of the casting box, and connect the water inlet pipeline with the casting box;
[0013] Step 3: Make sand cores. For confined spaces that are prone to cracks and sand sticking, use chromite sand to make sand cores. The sand cores made of chromite sand have high refractoriness and are not easy to sinter. In addition, chromite sand has a low thermal expansion coefficient and has better thermal stability than silica sand. High-temperature cracks rarely occur. Sand cores made of chromite sand will not have the problem of flash growing in the inner cavity.
[0014] Step 4: Make a C-shaped inspection fixture to detect the sand core assembly effect. If there is a deviation, the position of the sand core assembly can be adjusted in time. The size change after the sand core assembly can be accurately detected, and the wall thickness of the box and the size of the inner cavity of the box can be effectively controlled;
[0015] Step 5: Design the sand core head and make it a right-angle structure;
[0016] Step 6: Material smelting: pour the casting box material into the smelting furnace for smelting. After the casting box material is melted, remove the impurities on the surface of the smelting dish.
[0017] Step 7: pouring and molding, pouring the pouring liquid after smelting and impurity removal in step 6 into the casting mold optimized in steps 1 to 5, and forming the casting box after the pouring liquid is cooled;
[0018] Step 8: Open the box and take out the casting, manually open the casting sand box, and then take out the casting box formed inside the sand mold in the sand box;
[0019] Step nine: Cooling down, cooling the casting box after taking it out.
[0020] Preferably, the core box proposed in step 1 is made of cast aluminum material, and the thickness of the steel plate on the core box is 3 mm.
[0021] Preferably, the water inlet pipeline in step 2 uses two upper and lower branch pipelines, and the water inlet pipeline uses a ceramic tube.
[0022] Preferably, the sand thickness of the sand core in step three is 5-7 mm, and the space is closed. If flash and sand sticking occur here, the casting box can only be scrapped.
[0023] Preferably, the C-shaped gauge in step 4 is clamped on the sand core that is butt-jointed at the upper and lower sides.
[0024] Preferably, the method for removing impurities from the molten liquid in step six is a salvaging method, in which the impurities on the surface of the molten liquid are salvaged manually through a handheld filter net.
[0025] Preferably, the cooling method in step nine is a combination of natural cooling and water cooling. The casting box is naturally cooled for half an hour just after being taken out, and then immersed in a water pool to quickly cool the casting box by cooling water.
[0026] A thin-walled tram gearbox housing comprises a housing.
[0027] Preferably, the box body comprises an upper box body and a lower box body, and a cavity is provided between the upper box body and the lower box body.
[0028] (III) Beneficial effects
[0029] Compared with the prior art, the present invention provides a thin-walled tram gearbox housing and a casting process, which has the following beneficial effects:
[0030] 1. The thin-walled tram gearbox housing and casting process are designed with a special sand core right-angle structure core head and core assembly inspection fixture, which can effectively ensure the wall thickness (6±1mm) and contour position of the gearbox casting. The dimensional accuracy reaches GB / T6414-CT8 level, breaking through the CT11-CT13 level limit of traditional resin sand manual molding, and meeting the high-quality and high-precision grade requirements for large and medium-sized castings;
[0031] 2. The thin-walled tram gearbox housing and casting process creatively designs the ceramic tube water inlet process, which ensures rapid pouring while taking into account the uniform heat distribution in the solidification field of the casting, thereby achieving sequential solidification and ensuring that the casting has no cold shut, insufficient pouring, or white spots. The wall thickness of the box casting (6±1mm) has been greatly reduced, breaking through the industry convention of 10-15mm wall thickness for gearboxes.
[0032] 3. The thin-walled tram gearbox housing and casting process adopts a special chromite sand process for the oil channel and the sand core in a narrow and confined space, thereby ensuring that there are no flying wings and no sticking sand when the casting is cleaned. At the same time, it can prevent the gearbox from damaging the teeth due to the falling of flying wings and sticking sand when running at high speed, causing vehicle operation failures and even safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a structural schematic diagram of adding a steel plate to the core box proposed by the present invention;
[0034] Figure 2 This is a schematic diagram of the structure of the water inlet pipeline proposed by the present invention;
[0035] Figure 3 This is a schematic diagram of the structure of the C-shaped gauge proposed by the present invention;
[0036] Figure 4 This is a schematic structural diagram of the sand core head proposed by the present invention. DETAILED DESCRIPTION
[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0038] A thin-walled tram gearbox casting process, the specific steps are as follows:
[0039] Step 1: Add steel plate 2 to the casting mold, and pad the steel plate 2 on the sanded surface of the core box 1 of the casting mold to solve the problems of poor wear resistance of the aluminum mold surface, frequent sanding, great wear and large changes in the size of the sand core (such as Figure 1 );
[0040] Step 2: Design the ceramic tube ingate, set the water inlet pipe 3 at the thin wall at the far end of the lower box of the casting box, and connect the water inlet pipe 3 with the casting box (such as Figure 2 ), first, it effectively solves the problem that the water inlet of the casting can only be located on the parting surface, resulting in excessive heat concentration, and the casting is prone to shrinkage holes and shrinkage near the water inlet, while the thin wall at the far end is prone to cold shut, insufficient pouring, white cast and other defects; second, because the water inlet of the casting is located at the bottom of the casting, the molten iron can be ensured to be stable during pouring, turbulence, air entrainment, and splashing can be prevented, and the oxidation of the molten iron can be effectively prevented to ensure the purity of the molten iron; third, because the heat of the entire casting is evenly distributed, the casting realizes sequential solidification during the solidification process, reduces the use of chillers and risers, reduces the workload of molding operators in preparing chillers and risers, and effectively reduces production costs;
[0041] Step 3: Make sand cores. For confined spaces that are prone to cracks and sand sticking, use chromite sand to make sand cores. The sand cores made of chromite sand have high refractoriness and are not easy to sinter. In addition, chromite sand has a low thermal expansion coefficient and has better thermal stability than silica sand. High-temperature cracks rarely occur. Sand cores made of chromite sand will not have the problem of flash growing in the inner cavity.
[0042] Step 4: Make a C-shaped inspection fixture 4 to detect the sand core assembly effect. If there is a deviation, the position of the sand core assembly can be adjusted in time. The change in the size of the sand core after assembly can be accurately detected, and the wall thickness of the box and the size of the inner cavity of the box can be effectively controlled (such as Figure 3 );
[0043] Step 5: Design the core head of the sand core and design the core head of the sand core into a right-angle structure (such as Figure 4 );
[0044] Step 6: Material smelting: pour the casting box material into the smelting furnace for smelting. After the casting box material is melted, remove the impurities on the surface of the smelting dish.
[0045] Step 7: pouring and molding, pouring the pouring liquid after smelting and impurity removal in step 6 into the casting mold optimized in steps 1 to 5, and forming the casting box after the pouring liquid is cooled;
[0046] Step 8: Open the box and take out the casting, manually open the casting sand box, and then take out the casting box formed inside the sand mold in the sand box;
[0047] Step nine: Cooling down, cooling the casting box after taking it out.
[0048] The core box 1 proposed in step 1 is made of cast aluminum material, and the thickness of the steel plate 2 on the core box 1 is 3 mm.
[0049] The water inlet pipeline 3 in step 2 uses two upper and lower branch pipelines, and the water inlet pipeline 3 uses a ceramic tube.
[0050] The sand thickness of the sand core in step 3 is 5-7 mm, and the space is closed. If flash and sand sticking occur here, the casting box can only be scrapped.
[0051] The C-shaped gauge 4 in step 4 is clamped and arranged on the sand core that is butt-jointed at the upper and lower sides.
[0052] The method of removing impurities from the molten liquid in step six is a salvaging method, in which impurities on the surface of the molten liquid are salvaged manually by using a handheld filter net.
[0053] The cooling method in step nine is a combination of natural cooling and water cooling. The casting box is naturally cooled for half an hour just after being taken out, and then immersed in a water pool to quickly cool the casting box by cooling water.
[0054] A thin-walled tram gearbox housing comprises a housing, wherein the housing comprises an upper housing and a lower housing, and a cavity is arranged between the upper housing and the lower housing.
[0055] In summary, the thin-walled tram gearbox housing and casting process, in order to ensure the dimensional accuracy of the gearbox casting, adopts metal mold and resin sand technology in the casting process, which can effectively ensure the wall thickness, contour and position of the casting, and the dimensional accuracy reaches GB / T6414-CT8 level; a special chromite sand process is used on the oil channel and the sand core in a narrow and confined space to ensure that there are no flying wings and no sticking sand when the casting is cleaned, and at the same time, it can prevent the gearbox from damaging the teeth due to the falling of flying wings and sticking sand when running at high speed, causing locomotive operation failures and even safety accidents.
[0056] It should be noted that the term "comprises" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also includes other elements that are not explicitly listed, or also includes elements inherent to such process, method, article, or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.
[0057] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A casting process for a thin-walled tram gearbox housing, characterized in that: The specific steps are as follows: Step 1: adding a steel plate (2) to the casting mold, padding the steel plate (2) on the sanded surface of the core box (1) of the casting mold, to solve the problems of poor wear resistance of the aluminum mold surface, frequent sanding, severe wear and large changes in the size of the sand core; Step 2: Design a gate in the ceramic tube, and set a water inlet pipeline (3) at the thin wall at the far end of the lower box of the casting box, and the water inlet pipeline (3) is connected to the casting box; Step 3: Make sand cores. For confined spaces that are prone to cracks and sand sticking, use chromite sand to make sand cores. The sand cores made of chromite sand have high refractoriness and are not easy to sinter. In addition, chromite sand has a low thermal expansion coefficient and has better thermal stability than silica sand. High-temperature cracks rarely occur. Sand cores made of chromite sand will not have the problem of flash growing in the inner cavity. Step 4: Make a C-shaped inspection fixture (4) to detect the sand core assembly effect. If there is a deviation, the position of the sand core assembly can be adjusted in time. The change in the size of the sand core after assembly can be accurately detected, and the wall thickness of the box and the size of the inner cavity of the box can be effectively controlled; Step 5: Design the sand core head and make it a right-angle structure; Step 6: Material smelting: pour the casting box material into the smelting furnace for smelting. After the casting box material is melted, remove the impurities on the surface of the smelting dish. Step 7: pouring and molding, pouring the pouring liquid after smelting and impurity removal in step 6 into the casting mold optimized in steps 1 to 5, and forming the casting box after the pouring liquid is cooled; Step 8: Open the box and take out the casting, manually open the casting sand box, and then take out the casting box formed inside the sand mold in the box; Step nine: Cooling down, cooling the casting box after taking it out.
2. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The core box (1) proposed in step 1 is made of cast aluminum material, and the thickness of the steel plate (2) on the core box (1) is 3 mm.
3. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The water inlet pipeline (3) in step 2 uses two upper and lower branch pipelines, and the water inlet pipeline (3) uses a ceramic tube.
4. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The sand thickness of the sand core in step 3 is 5-7 mm, and the space is closed. If flash and sand sticking occur here, the casting box can only be scrapped.
5. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The C-shaped gauge (4) in step 4 is clamped and arranged on the sand core which is butt-jointed at the upper and lower sides.
6. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The method of removing impurities from the molten liquid in step six is a salvaging method, in which impurities on the surface of the molten liquid are salvaged manually by using a handheld filter net.
7. The casting process for a thin-walled tram gearbox housing according to claim 1, characterized in that: The cooling method in step nine is a combination of natural cooling and water cooling. The casting box is naturally cooled for half an hour just after being taken out, and then immersed in a water pool to quickly cool the casting box by cooling water.
8. A thin-walled tram gearbox housing, characterized in that: A box body manufactured by the casting process according to any one of claims 1 to 7.
9. A thin-walled tram gearbox housing according to claim 8, characterized in that: The box body comprises an upper box body and a lower box body, and a cavity is arranged between the upper box body and the lower box body.