A new energy mining truck double-motor main shell low-pressure casting mold and a casting process

Abstract

This invention discloses a low-pressure casting mold for the main housing of a dual-motor mining truck in a new energy vehicle, comprising a bottom mold, two side molds, and an upper mold. The upper mold is fitted with two detachable water-cooled steel cores. The bottom mold has a gate at the center of the corresponding motor cavity. The portion above the runner that cannot be molded is formed using a sand core. The water-cooled steel core includes an outer steel core sleeve and an inner steel core cylinder. The inner wall of the outer steel core sleeve has five annular water channels running from top to bottom. Multiple risers are provided on the upper mold at the contact points between the upper ends of the two side molds and the upper mold. This invention features a multi-layered water-cooling design on the steel core, achieving sequential solidification through the water-cooling structure and controlled opening time, thus solving defect problems. The use of a double-gate overlapping oblique cross runner and risers for feeding improves the internal quality of the casting. By rationally setting the low-pressure pouring parameters, mold temperature, and steel core water-cooling opening parameters, sequential solidification is achieved, resulting in a high overall quality of the produced dual-motor main housing and improved yield.

Description

Technical Field

[0001] This invention relates to the field of motor housing casting technology, and more specifically, to a low-pressure casting mold and casting process for the main housing of a dual motor in a new energy mining truck. Background Technology

[0002] In recent years, with the rapid development of new energy mining trucks, the dual-motor main housing, as a key component, plays a decisive role in the power transmission, stability, and reliability of the entire vehicle. Traditional casting processes present numerous problems in producing such complex main housing structures, for example: 1. Due to the complex structure of the dual-motor main housing, which contains many reinforcing ribs, oil holes, mounting holes, etc., it is difficult to ensure uniform filling of molten metal using ordinary casting molds and processes. This can easily lead to defects such as incomplete pouring and cold shut, resulting in a low product qualification rate.

[0003] 2. Traditional casting processes cannot effectively expel gas from inside the mold, resulting in defects such as porosity inside the casting and undercast reinforcing ribs on the surface, which affect the mechanical properties and service life of the main shell.

[0004] 3. The existing casting mold's cooling system design is unreasonable, resulting in uneven cooling of the castings and the inability to form effective sequential solidification, leading to numerous shrinkage defects inside the motor holes and affecting product performance.

[0005] 4. The casting production efficiency is low, making it difficult to meet the growing demand in the new energy mining truck market. Therefore, it is urgent to design a dedicated low-pressure casting mold and casting process to solve the above problems and improve the casting quality and production efficiency of the dual-motor main housing for new energy mining trucks. Summary of the Invention

[0006] The purpose of this invention is to provide a low-pressure casting mold and casting process for the main housing of a dual-motor mining truck in a new energy mining vehicle.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-pressure casting mold for the main housing of a dual motor of a new energy mining truck includes a bottom mold, two side molds and an upper mold. The two side molds are fixedly installed on the bottom mold by guide keys. The upper mold is equipped with two detachable water-cooled steel cores. The outer wall of the water-cooled steel cores and the inner wall of the side molds and the upper and bottom molds form a dual motor housing. The bottom mold has a gate at the center of the corresponding motor cavity. The gate is fed by overlapping the outer side of the housing through an oblique cross-shaped horizontal runner. The part above the runner that cannot be molded is formed by sand core molding. The water-cooled steel core includes a steel core outer sleeve and a steel core inner cylinder. The steel core outer sleeve is fitted on the steel core inner cylinder. The inner wall of the steel core outer sleeve has five annular water channels from top to bottom. Each annular water channel is connected to a circulating cooling water pipe. The upper end of the two side molds is in contact with the upper mold at multiple top risers. The lower end of the top risers is connected to the two motor cavities respectively.

[0008] Preferably, the side mold adopts a multi-layer insert structure, and the mating surface between the insert and the main body of the side mold is machined with a 0.1-0.15mm venting groove. Preferably, the inner steel core cylinder and the outer steel core cylinder are interference-fitted.

[0009] Preferably, a partition block is fixedly provided inside the annular water channel.

[0010] Preferably, the circulating cooling water pipe includes an inlet pipe and an outlet pipe, which are located on both sides of the partition block.

[0011] A casting process for a low-pressure casting mold for the main housing of a dual-motor mining truck in a new energy vehicle includes the following steps: S1. Before assembling the water-cooled steel core, the inner cylinder of the steel core is cooled with liquid nitrogen. S2. Place the steel core outer sleeve into an oven for heating, and then press it tightly into the steel core inner sleeve after heating. S3. Preheat the side mold, upper mold, water-cooled steel core and bottom mold to 320-360℃, 350-380℃ and 420-450℃ respectively. S4. By pressurizing the molten aluminum in the holding furnace, the molten aluminum enters the mold cavity through the gate on the bottom mold via the riser pipe to form low-pressure casting. S5. During the pouring process, water cooling is controlled through inlet and outlet pipes for multiple annular water channels.

[0012] Preferably, the water cooling control steps are as follows: the five annular water channels of the steel core outer sleeve from bottom to top are labeled as H1, H2, H3, H4 and H5 respectively, and the time is counted from the start of the air intake pouring; Water is introduced into H3 for water cooling after 25 seconds of air intake, and the water cooling time is 60 seconds. Water is introduced into H4 for water cooling after 30 seconds of air intake, and the water cooling time is 55 seconds. Water is introduced into H2 and H5 for water cooling after 35 seconds of air intake, and the water cooling time is 50 seconds. Water is introduced into H1 for water cooling after 45 seconds of air intake, and the water cooling time is 40 seconds.

[0013] Preferably, the low-pressure casting is divided into five steps, namely S1, S2, S3, S4, and S5. S1 pressure is 260 mbar, time is 16 seconds; S2 pressure is 450 mbar, time is 12 seconds; S3 pressure is 450 mbar, time is 2 seconds; S4 pressure is 650 mbar, time is 4 seconds; The S5 pressure is 650 mbar, and the time is 800-900 seconds.

[0014] Compared with the prior art, the advantages of the present invention are as follows: The present invention designs a multi-layer water cooling system on the steel core, and controls the temperature gradient of the steel core by controlling the water cooling opening time to achieve sequential solidification and solve the defect problem; the use of double gates and top risers for feeding improves the overall quality of the casting; by reasonably setting the low-pressure pouring parameters, mold temperature and steel core water cooling opening parameters to achieve sequential solidification, the produced dual-motor main housing has good internal quality and improves the yield. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a perspective view of a low-pressure casting mold for the main housing of a dual-motor mining truck according to the present invention. Figure 2 This is a structural diagram of the upper mold and water-cooled steel core of the present invention; Figure 3 This is a cross-sectional view of the steel core outer sleeve of the present invention; Figure 4 This is a cross-sectional view of the steel core inner cylinder of the present invention; Figure 5 This is a shrinkage porosity image of the casting blank of Embodiment 1 of the water-cooled steel core of the present invention. Figure 6 This is a shrinkage porosity image of the casting blank of Embodiment 2 of the water-cooled steel core of the present invention; Figure 7 This is a shrinkage porosity diagram of the casting blank of Example 3 of the water-cooled steel core of the present invention.

[0017] In the diagram: 1. Side mold; 2. Bottom mold; 3. Water-cooled steel core; 31. Steel core outer sleeve; 311. Annular water channel; 312. Partition block; 32. Steel core inner cylinder; 4. Circulating cooling water pipe fittings; 41. Water inlet pipe; 42. Water outlet pipe; 5. Gate; 6. Top riser; 7. Angled horizontal runner; 8. Upper mold. Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0019] See Figures 1-4 As shown, this invention provides a low-pressure casting mold for the main housing of a dual-motor mining truck, including a bottom mold 2, two side molds 1, and an upper mold 8. To more clearly illustrate the mold structure, Figure 1 One of the side molds 1 and the upper mold 8 are hidden. Both side molds 1 are fixedly installed on the bottom mold 2 by guide keys. The upper mold 8 is equipped with two detachable water-cooled steel cores 3. The outer wall of the water-cooled steel core 3 forms a double motor housing between the inner wall of the side mold 1 and the bottom mold 2 of the upper mold 8. The bottom mold 2 has a gate 5 at the center of the corresponding motor cavity. The gate 5 is connected to the outer side of the housing by an oblique cross-shaped horizontal runner 7 for shrinkage compensation. The part above the runner that cannot be molded is formed by sand core molding. The water-cooled steel core 3 includes a steel core outer sleeve 31 and a steel core inner cylinder 32. The steel core outer sleeve 31 is fitted on the steel core inner cylinder 32. The inner wall of the steel core outer sleeve 31 has five annular water channels 311 from top to bottom. The annular water channels 311 are all connected to circulating cooling water pipes 4. The upper end of the two side molds 1 is in contact with the upper mold 8 at the upper mold 8. The lower end of the top riser 6 is connected to the two motor cavities respectively.

[0020] In this embodiment, the side mold 1 adopts a multi-layer insert structure, and the mating surface between the insert and the main body of the side mold 1 is machined with a 0.1-0.15mm venting groove.

[0021] By using the gaps between the inserts, the problem of insufficient air filling at the rib positions of the main shell can be solved, thereby enabling the smooth filling of complex external structures.

[0022] In this embodiment, the inner steel core cylinder 32 and the outer steel core cylinder 31 are interference-fitted.

[0023] Furthermore, in order to improve the circulation speed of cooling water, in this embodiment, a partition block 312 is fixedly provided inside the annular water channel 311.

[0024] In this embodiment, the circulating cooling water pipe 4 includes an inlet pipe 41 and an outlet pipe 42, which are located on both sides of the partition block 312.

[0025] In this embodiment, the gate 5 is fed by overlapping the outer side of the shell with the oblique cross runner 7 to reduce the turbulence of the molten metal.

[0026] A casting process for a low-pressure casting mold for the main housing of a dual-motor mining truck in a new energy vehicle includes the following steps: S1. Before assembling the water-cooled steel core 3, the inner cylinder 32 of the steel core is cooled with liquid nitrogen for a period of not less than 30 minutes. S2. Place the steel core outer sleeve 31 into an oven for heating. After heating, it is tightly assembled with the steel core inner sleeve 32. The heating temperature is 400±30 degrees and the heating time is 30-40 minutes. S3. Preheat the side mold 1, the upper mold 8, the water-cooled steel core 3, and the bottom mold 2 at preheating temperatures of 320-360℃, 350-380℃, and 420-450℃, respectively. S4. By pressurizing the molten aluminum in the holding furnace, the molten aluminum enters the mold cavity through the riser pipe from the gate 5 on the bottom mold 2 to form a low-pressure pouring; by using double gates 5 and top risers 6 for feeding, the overall quality of the casting is improved. S5. During the pouring process, the water cooling of multiple annular water channels 311 is controlled by the water inlet pipe 41 and the water outlet pipe 42.

[0027] The five annular water channels 311 of the steel core outer sleeve 31 from bottom to top are labeled H1, H2, H3, H4 and H5 respectively, with the time counted from the start of air intake pouring; the parameters for water cooling of the water-cooled steel core in Example 1 are as follows: Onset time point 25 30 35 40 45 Water cooling on duration / s 40 45 50 55 60 The flaw detection of the casting is as follows Figure 5 As shown; The parameters for Example 2 of water-cooled steel core are as follows: Onset time point 45 40 35 30 25 Water cooling on duration / s 60 55 50 45 40 The flaw detection of the casting is as follows Figure 6 As shown; The parameters for Example 3 of water-cooled steel core are as follows: Water is introduced into H3 for water cooling after 25 seconds of air intake, and the water cooling time is 60 seconds. Water is introduced into H4 for water cooling after 30 seconds of air intake, and the water cooling time is 55 seconds. Water is introduced into H2 and H5 for water cooling after 35 seconds of air intake, and the water cooling time is 50 seconds. Water is introduced into H1 for water cooling after 45 seconds of air intake, and the water cooling time is 40 seconds.

[0028] The low-pressure casting process is divided into five steps, namely S1, S2, S3, S4, and S5. S1 pressure is 260 mbar, time is 16 seconds; S2 pressure is 450 mbar, time is 12 seconds; S3 pressure is 450 mbar, time is 2 seconds; S4 pressure is 650 mbar, time is 4 seconds; The S5 pressure is 650 mbar, and the time is 800-900 seconds.

[0029] Under the above parameters, the flaw detection results of the casting are as follows: Figure 7 As shown in the comparative test, using the above low-pressure casting parameters and mold temperature, the production of the dual-motor main housing under the condition of steel core water cooling parameter 3 was good in terms of flaw detection, and the overall quality of the produced dual-motor main housing was good with a high yield.

[0030] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, the patent owner may make various modifications or alterations within the scope of the appended claims, as long as they do not exceed the protection scope described in the claims of the present invention, they shall be within the protection scope of the present invention.

Claims

1. A casting process for a low-pressure casting mold for the main housing of a dual-motor mining truck in a new energy vehicle, the casting mold comprising a bottom mold, two side molds, and an upper mold, characterized in that: Both side molds are fixedly installed on the bottom mold by guide keys. The upper mold is equipped with two detachable water-cooled steel cores. The outer wall of the water-cooled steel cores forms a double motor housing with the inner wall of the side molds and the upper and bottom molds. The bottom mold has a gate at the center of the corresponding motor cavity. The gate is fed by overlapping the outer side of the housing through an oblique cross-shaped horizontal runner. The part above the runner that cannot be molded is formed with a sand core. The water-cooled steel core includes a steel core outer sleeve and a steel core inner cylinder. The steel core outer sleeve is fitted on the steel core inner cylinder. The inner wall of the steel core outer sleeve has five annular water channels from top to bottom. The annular water channels are all connected to circulating cooling water pipes. The circulating cooling water pipes include inlet pipes and outlet pipes. The upper end of the two side molds has multiple top risers at the contact position with the upper mold. The lower end of the top risers is connected to the two motor cavities respectively. The casting process includes the following steps: S1. Before assembling the water-cooled steel core, the inner cylinder of the steel core is cooled with liquid nitrogen. S2. Place the steel core outer sleeve into an oven for heating, and then press it tightly into the steel core inner sleeve after heating. S3. Preheat the side mold, upper mold, water-cooled steel core and bottom mold to 320-360℃, 350-380℃ and 420-450℃ respectively. S4. By pressurizing the molten aluminum in the holding furnace, the molten aluminum enters the mold cavity through the gate on the bottom mold via the riser pipe to form low-pressure casting. S5. During the pouring process, the five annular water channels are water-cooled through the inlet and outlet pipes.

2. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 1, characterized in that: The side mold adopts a multi-layered insert structure, and the mating surface between the insert and the main body of the side mold is machined with a 0.1-0.15mm venting groove.

3. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 1, characterized in that: The inner steel core cylinder and the outer steel core cylinder are interference-fitted.

4. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 1, characterized in that: A partition block is fixedly installed inside the annular water channel.

5. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 4, characterized in that: The inlet pipe and outlet pipe are located on both sides of the partition block.

6. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 1, characterized in that: The water cooling control steps are as follows: label the five annular water channels of the steel core outer sleeve from bottom to top as H1, H2, H3, H4 and H5 respectively, starting from the start of the air intake pouring; Water is introduced into H3 for water cooling after 25 seconds of air intake, and the water cooling time is 60 seconds. Water is introduced into H4 for water cooling after 30 seconds of air intake, and the water cooling time is 55 seconds. Water is introduced into H2 and H5 for water cooling after 35 seconds of air intake, and the water cooling time is 50 seconds. Water is introduced into H1 for water cooling after 45 seconds of air intake, and the water cooling time is 40 seconds.

7. The casting process of a low-pressure casting mold for the main housing of a dual-motor new energy mining truck according to claim 1, characterized in that: The low-pressure casting process is divided into five steps, namely S1, S2, S3, S4, and S5. S1 pressure is 260 mbar, time is 16 seconds; S2 pressure is 450 mbar, time is 12 seconds; S3 pressure is 450 mbar, time is 2 seconds; S4 pressure is 650 mbar, time is 4 seconds; The S5 pressure is 650 mbar, and the time is 800-900 seconds.

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