A stamping method for aluminum alloy housing

Abstract

This invention discloses a stamping forming method for aluminum alloy housings, which can reduce material consumption and manufacturing costs, and improve work efficiency. The stamping forming method for aluminum alloy housings includes: Step 1, obtaining an aluminum alloy tube, wherein the inner diameter of the aluminum alloy tube is equal to the inner diameter of the formed aluminum alloy housing, and the outer diameter of the aluminum alloy tube is equal to the outer diameter of the formed aluminum alloy housing; Step 2, using a stamping process, axially stacking the aluminum alloy tube outwards to form an outer stacked portion; Step 3, using a stamping process, axially stacking the aluminum alloy tube into the inner cavity of the tube to form an inner stacked portion; Step 4, performing partial lateral stamping on the outer stacked portion to form an outer channel, thereby producing the aluminum alloy housing.

Description

Technical Field

[0001] This invention relates to the field of stamping, specifically to a stamping method for aluminum alloy housings. Background Technology

[0002] The harmonic reducer motor housing features a lightweight design, using 6061-T6 aluminum alloy, which boasts excellent strength, thermal conductivity, lightweight construction, and corrosion resistance. However, due to the high strength and low ductility of 6061-T6 aluminum alloy, traditional manufacturing methods often involve die casting or cold extrusion followed by machining. Die casting or cold extrusion suffer from low precision, long processing cycles, and require larger machining allowances, leading to significant material waste, prolonged subsequent machining time, and low production efficiency, resulting in high overall production costs for the motor housing. For example, manufacturing a 2.5mm thick motor housing using traditional methods requires first obtaining a 7.5mm thick aluminum tube, then CNC machining to achieve the desired shape and dimensions. Although the aluminum shell wall thickness is 2.5mm, the product has bosses on the inner and outer walls. Traditionally, this is achieved by turning to remove material; to accommodate these bosses, a thicker tube must be selected for machining to meet this structural requirement. Therefore, traditional methods cannot directly use 2.5 mm aluminum tubes. Traditional methods involve using thicker aluminum tubes and machining them with a CNC lathe to remove material, resulting in high material consumption. Traditional methods also involve using a CNC lathe to machine the inner and outer diameters of the housing, which is time-consuming, inefficient, and requires a large investment in processing equipment for mass production. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a stamping method for aluminum alloy housings, which reduces material consumption and manufacturing costs and improves work efficiency.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for stamping an aluminum alloy housing, the housing being tubular, comprising a shell, an outer stacked portion located outside the shell, and an inner stacked portion located within the shell cavity, the outer stacked portion having an outer channel; the method includes:

[0006] Step 1: Obtain the aluminum alloy tube. The inner diameter of the aluminum alloy tube is equal to the inner diameter of the formed aluminum alloy housing, and the outer diameter of the aluminum alloy tube is equal to the outer diameter of the formed aluminum alloy housing.

[0007] Step 2: Using a stamping process, the aluminum alloy tube body is axially stacked to extend outwards to form an outer stacked section;

[0008] Step 3: Using a stamping process, the aluminum alloy tube body is axially stacked, extending into the inner cavity of the tube body, to form an inner stacked section;

[0009] Step 4: Perform partial lateral stamping on the outer stacked material to form an outer channel, thereby producing an aluminum alloy housing.

[0010] As a preferred example, the inner diameter of the aluminum alloy tube is 50-55 mm, and the outer diameter is 56-60 mm.

[0011] As a preferred example, the material of the aluminum alloy tube is aluminum alloy 6061-T6.

[0012] As a preferred example, in step 2, an annular groove is formed on the inner side of the outer stacked material, and the vertical projection of the annular groove is located in the shell.

[0013] As a preferred example, step 3 includes:

[0014] Step 301: Using a stamping process, the aluminum alloy tube body is narrowed inward N times; where N is an integer and N≥2, forming a lower stacked part with an arc-shaped end face; the upper outer part of the lower stacked part forms a first rounded corner where it connects with the shell, and the lower inner part of the lower stacked part forms a second rounded corner where it connects with the shell, the second rounded corner being equal to the rounded corner where the lower inner part of the inner stacked part connects with the shell;

[0015] Step 302: Stamp and shape the lower stacked part to reduce the first rounded corner and change the shape of the lower stacked part. The cross-section of the lower stacked part changes from an arc shape to an inclined straight line.

[0016] Step 303: Widen the upper part of the lower stacked part of the aluminum alloy tube after step 302 to form an upper stacked part between the lower stacked part and the upper shell. A third rounded corner is formed between the upper interior of the upper stacked part and the upper shell. The upper stacked part and the lower stacked part form an inner stacked part.

[0017] Step 304: Stamp and shape the upper stacked part to reduce the third rounded corner and make the top of the upper stacked part flat. Adjust the diameter of the hollow cavity of the inner stacked part and the distance from the top of the upper stacked part to the end face of the shell to meet the process requirements, thereby making the inner stacked part.

[0018] As a preferred example, in step 301, the necking is performed N times, and the necking ratio of each time is greater than the necking ratio of the next time.

[0019] As a preferred example, in step 301, N=2; the first shrinkage ratio is less than 10%, and the second shrinkage ratio is less than 8%.

[0020] As a preferred example, step 4 includes: placing the aluminum alloy tube body processed in step 3 into the lower mold, inserting a mandrel into the aluminum alloy tube body, the diameter of the mandrel being equal to the inner diameter of the aluminum alloy tube body; using a side-pressing forming method, the side-pressing punch, through the lateral force converted when the punch presses down, laterally extrudes a portion of the outer stacked material of the aluminum alloy tube body, extruding the portion of the outer stacked material into the annular groove of the outer stacked material, and the extruded portion of the outer stacked material forms an outer channel; the outer channel divides the outer stacked material, and the bottom surface of the outer channel is the shell surface.

[0021] As a preferred example, the method is implemented using a multi-station punch press, which is equipped with a stacking station, a first necking station, a second necking station, a first shaping station, a flaring station, a second shaping station, and a side punching station; the time to prepare one of the housings by the method and the punch press is in the order of seconds.

[0022] As a preferred example, the housing is used as the housing of a harmonic reducer.

[0023] Compared with existing technologies, the stamping forming method for aluminum alloy housings of the present invention can reduce material consumption and manufacturing costs, and improve work efficiency. The stamping forming method for aluminum alloy housings includes: obtaining an aluminum alloy tube, wherein the inner diameter of the aluminum alloy tube is equal to the inner diameter of the formed aluminum alloy housing, and the outer diameter of the aluminum alloy tube is equal to the outer diameter of the formed aluminum alloy housing; using a stamping process, axially stacking the aluminum alloy tube outward to form an outer stacked portion; using a stamping process, axially stacking the aluminum alloy tube into the inner cavity of the tube to form an inner stacked portion; and performing partial lateral stamping on the outer stacked portion to form an outer channel, thereby producing an aluminum alloy housing. The method of this invention can be used to manufacture harmonic reducer housings for humanoid robots. By employing stamping forming combined with stacking, necking, hole expansion, and shaping processes, it solves the problem of high housing manufacturing costs and achieves lightweight and efficient mass production. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the aluminum alloy tube obtained in step 1 of this embodiment of the invention;

[0025] Figure 2 This is a cross-sectional view of the aluminum alloy tube after processing in step 2 of this embodiment of the invention;

[0026] Figure 3 This is a cross-sectional view of the aluminum alloy tube after the first narrowing in step 301 of the embodiment of the present invention;

[0027] Figure 4 This is a cross-sectional view of the aluminum alloy tube after the second necking in step 301 of this embodiment of the invention;

[0028] Figure 5This is a cross-sectional view of the aluminum alloy tube after the processing in step 302 of this embodiment of the invention;

[0029] Figure 6 This is a cross-sectional view of the aluminum alloy tube after the processing in step 303 of this embodiment of the invention;

[0030] Figure 7 This is a cross-sectional view of the aluminum alloy tube after processing in step 304 of this embodiment of the invention;

[0031] Figure 8 This is a cross-sectional view of the aluminum alloy tube after processing in step 4 of this embodiment of the invention;

[0032] Figure 9 This is an assembly drawing of the aluminum alloy tube and the mold in step 302 of the present invention;

[0033] Figure 10 This is an assembly drawing of the aluminum alloy tube and the mold in step 303 of the present invention;

[0034] Figure 11 This is an assembly diagram of the aluminum alloy tube and the mold in step 304 of the present invention.

[0035] The diagram includes: shell 1, outer stacking part 2, inner stacking part 3, lower stacking part 31, upper stacking part 32, outer channel 4, mandrel 5, lower mold 6, upper mold 7, upper push block 8, upper mandrel 9, and lower mandrel 10. Detailed Implementation

[0036] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0037] The aluminum alloy housing in this embodiment of the invention can be used as the housing of a harmonic reducer. The housing is tubular. The housing includes a shell 1, an outer stacked portion 2 located outside the shell 1, and an inner stacked portion 3 located inside the shell 1. The outer stacked portion 2 has an outer channel 4. The outer stacked portion 2 can be used to assemble and position the harmonic reducer. The inner stacked portion 3 is used to support the bearing in the harmonic reducer. The bearing is installed on the upper part of the inner stacked portion 3. During operation, the bearing generates a downward impact force (towards the top surface of the inner stacked portion 3). The outer channel 4 can be used for assembly positioning to avoid assembly interference.

[0038] An embodiment of the present invention provides a stamping method for an aluminum alloy housing, comprising:

[0039] Step 1, as follows Figure 1 As shown, an aluminum alloy tube is obtained, with its inner diameter equal to the inner diameter of the formed aluminum alloy housing, and its outer diameter equal to the outer diameter of the formed aluminum alloy housing. Based on the housing specifications, the wall thickness and inner and outer diameters of the aluminum tube are precisely set, and the aluminum alloy tube is cut to the required stamping length.

[0040] Step 2, as follows Figure 2 As shown, the aluminum alloy tube body is axially stacked to the outside of the tube body using a stamping process to form the outer stacked part 2.

[0041] Step 3: Using a stamping process, the aluminum alloy tube body is axially stacked, extending into the inner cavity of the tube body, to form the inner stacked part 3.

[0042] Step 4: Perform partial lateral stamping on the outer stacked material 2 to form the outer channel 4, thereby producing an aluminum alloy housing.

[0043] In the method of the above embodiments, the inner diameter of the aluminum alloy tube is equal to the inner diameter of the formed aluminum alloy housing, the outer diameter of the aluminum alloy tube is equal to the outer diameter of the formed aluminum alloy housing, and the wall thickness of the aluminum alloy tube is equal to the wall thickness of the formed aluminum alloy housing. Thus, compared with existing methods, the method of the present invention does not cause material waste during the forming process. Preferably, the inner diameter of the aluminum alloy tube is 50-55 mm, and the outer diameter is 56-60 mm. For example, the inner diameter of the aluminum alloy tube is 51 mm, and the outer diameter is 56 mm. Using a stamping process, the aluminum alloy tube is axially stacked outwards to form an outer stacked portion 2; and axially stacked into the inner cavity of the tube is formed an inner stacked portion 3. Using a stamping process to prepare the outer stacked portion 2 and the inner stacked portion 3 can save materials, reduce processing time, and improve processing efficiency.

[0044] Preferably, in step 1, the aluminum alloy tube is made of aluminum alloy 6061-T6. This material is both lightweight and strong, meeting the process requirements. Of course, those skilled in the art can also choose other aluminum alloy materials.

[0045] Preferably, in step 2, an annular groove is formed on the inner side of the outer stacked material portion 2, and the vertical projection of the annular groove is located in the housing 1. The top end of the annular groove communicates with the inner cavity of the housing 1, the bottom end of the annular groove is located in the housing 1, and the vertical projection of the annular groove is located in the vertical projection of the housing 1. That is to say, the bottom end of the annular groove does not protrude from the outer wall surface of the housing 1.

[0046] Step 2 specifically includes: placing the aluminum alloy tube in the lower die on a punch press. The inner wall of the lower die has a concave outer stacking area. A mandrel is placed in the hollow cavity of the aluminum alloy tube. The outer diameter of the mandrel is equal to the inner diameter of the aluminum alloy tube. The upper die punch presses the top of the aluminum alloy tube downwards, causing some of the material to flow into the outer stacking area, forming the outer stacking section. The mandrel is used to prevent the material from flowing into the inner cavity of the aluminum alloy tube during the punching process. The distance from the outer stacking section 2 to the top of the aluminum alloy tube is the process-defined distance. The thickness of the outer stacking section 2 is the process-defined thickness. For example, the thickness of the outer stacking section 2 is 5-10 mm, and the distance from the outer stacking section 2 to the top of the aluminum alloy tube is 25-35 mm.

[0047] By controlling the stroke of the upper and lower dies and the precision of the mold, the thickness of the outer stacked part 2 and the distance from the outer stacked part 2 to the port of the aluminum alloy tube are guaranteed.

[0048] Preferably, step 3 includes:

[0049] Step 301: Using a stamping process, the aluminum alloy tube body is narrowed inward N times; where N is an integer and N≥2, forming a lower stacked part 31 with an arc-shaped end face; the upper outer part of the lower stacked part 31 forms a first rounded corner at the connection with the shell 1, and the lower inner part of the lower stacked part 31 forms a second rounded corner at the connection with the shell 1, the second rounded corner being equal to the rounded corner at the connection with the lower inner part of the inner stacked part 3 and the shell 1.

[0050] In step 301, during the necking process, the aluminum alloy tube is placed in the lower die, and a mandrel of a predetermined diameter, smaller than the inner diameter of the aluminum alloy tube, is placed inside the tube. A punch press is used, with a die mounted on the press slide. The inner hole of the die is designed according to the outer wall of the necking section of the aluminum alloy tube. By pressing down the press slide, the die reduces the opening of the aluminum alloy tube, and the mandrel limits the range of diameter reduction. The necking process is performed on the portion of the aluminum alloy tube to be necked, so that the inner diameter of the necking section is equal to the diameter of the placed mandrel. For the next necking operation, a smaller diameter mandrel is used, employing the same method.

[0051] In step 301 above, multiple necking operations are performed, with each necking ratio being greater than the last. Aluminum alloy tubes have high strength but poor plasticity. If processing is completed in a single necking operation, the large necking ratio will cause the aluminum alloy tube to crack. After one necking operation, the aluminum alloy material undergoes plastic deformation, increasing its work hardening strength. Subsequent necking operations require smaller necking ratios; otherwise, if a larger necking ratio is used later, it will be difficult to overcome the risks associated with work hardening, and the material will crack. Therefore, this embodiment uses multiple necking operations, with each necking ratio being greater than the last. The necking ratio is the ratio of the difference between the inner diameter of the tube before necking and the inner diameter of the tube after necking to the inner diameter of the tube before necking.

[0052] Preferably, in step 301, the necking is performed twice. The first necking percentage is less than 10%, and the second necking percentage is less than 8%, with the first necking percentage being greater than the second. Because aluminum alloy has high strength, the necking percentage cannot be too large; otherwise, cracking will occur after necking. For example, ... Figure 3 As shown, the diameter of the aluminum alloy tube before the first necking was 51.7 mm, and the diameter after necking was 47.4 mm. The necking ratio for the first necking was (51.7-47.4) / 51.7=8.3%. Figure 4 As shown, the diameter of the aluminum alloy tube before the second necking is 47.4 mm, and the diameter of the aluminum alloy tube after necking is 45.7 mm. The necking ratio of the second necking is (47.4-45.7) / 47.4=3.6%.

[0053] Step 302, as follows Figure 5 As shown, the lower stacked material section 31 is stamped and shaped to reduce the first rounded corner and change the shape of the lower stacked material section 31. The cross-section of the lower stacked material section 31 changes from an arc shape to an inclined straight line shape.

[0054] In step 302, as Figure 9As shown, an aluminum alloy tube is placed in the lower die 6, and a mandrel 5 is placed inside the aluminum alloy tube, penetrating the inner cavity of the tube. The front end of the mandrel 5 has a protrusion opposite to the lower surface of the lower stacked portion 31 of the aluminum alloy tube, and this protrusion is inclined. An upper die 7 is installed on the press slide. The upper die 7 is contoured according to the outer surface of the aluminum alloy tube, and the inner side of its bottom end is inclined. By pressing down on the press, the inner side of the bottom end of the upper die 7 is pressed against the outer surface of the lower stacked portion 31, applying pressure to it. With the cooperation of the protrusion of the mandrel 5, the cross-section of the lower stacked portion 31 changes from an arc shape to an inclined straight line. Changing the shape of the lower stacked portion 31 changes its cross-section from an arc shape to an inclined straight line. This change in shape allows the lower stacked portion 31 to withstand the downward impact force generated by the bearing of the harmonic reducer located above it during operation. During operation, the downward impact force of the bearing can exceed 1000 Newtons. If the cross-section is arc-shaped, the lower stacked section 31 is prone to cracking and cannot effectively withstand impact forces. Simultaneously, by compressing the lower stacked section 31, the material becomes denser, which helps it withstand the downward impact force generated during bearing operation. Meanwhile, an upper push block 8 is installed on the upper mold 7, with its bottom end facing the top end of the aluminum alloy tube. After forming, the upper push block 8 detaches the aluminum alloy tube from the upper mold hole.

[0055] Step 303, as follows Figure 6 As shown, the lower stacked portion 31 of the aluminum alloy tube after step 302 is flared, and an upper stacked portion 32 is formed between the lower stacked portion 31 and the upper shell 1. A third rounded corner is formed between the upper interior of the upper stacked portion 32 and the upper shell 1. The upper stacked portion 32 and the lower stacked portion 31 form an inner stacked portion 3.

[0056] In step 303, such as Figure 10 As shown, an aluminum alloy tube is placed in the lower die 6, and a lower mandrel 10 is placed inside the inner cavity of the aluminum alloy tube. The top of the lower mandrel 10 contacts the bottom surface of the lower stacked part 31, so that the lower stacked part 31 will not change position or shape during subsequent flaring. An upper mandrel 9 is installed on the slide of the punch press. The front end of the upper mandrel 9 has a guide part, and the rod body of the upper mandrel 9 is cylindrical. The connection between the guide part and the rod body is an arc-shaped transition part. During operation, the punch press presses down, and the guide part of the upper mandrel 9 first enters the aluminum alloy tube. As the punch press continues to press down, the rod body of the upper mandrel 9 enters the aluminum alloy tube, expanding the inner wall of the aluminum alloy tube. When the punch press is pressed down to the lowest position, the part of the aluminum alloy tube corresponding to the arc-shaped transition part is the upper stacked part 32. The upper stacked part 32 and the lower stacked part 31 are directly connected. In step 303, the inner stacked part 3 of the housing is pre-formed by the hole expansion process. The upper stacked section 32 and the lower stacked section 31 form a similar inclined V-shape.

[0057] Step 304, as Figure 7As shown, the upper stacked part is stamped and shaped to reduce the third rounded corner and make the top of the upper stacked part 32 flat. The diameter of the hollow cavity of the inner stacked part 3 and the distance from the top of the upper stacked part 32 to the end face of the shell 1 are adjusted to meet the process requirements, thereby making the inner stacked part 3.

[0058] In step 304, such as Figure 11 As shown, the aluminum alloy tube processed in step 303 is placed in the lower die 6, and a lower mandrel 10 is placed inside the aluminum alloy tube. The top of the lower mandrel 10 is adapted to the bottom surface of the lower stacked part 31 and the inner end face of the upper stacked part 32. An upper die 7 is installed on the slide of the punch press. The inner hole of the upper die is designed according to the outer wall of the aluminum alloy tube, covering the outer wall of the aluminum alloy tube to prevent the material from expanding outward after extrusion. An upper mandrel 9 is installed inside the upper die 7. The outer diameter of the upper mandrel 9 is equal to the inner diameter of the aluminum alloy tube. The bottom surface of the upper mandrel 9 is flat, and a rounded corner is provided between the bottom surface of the upper mandrel 9 and the outer wall of the upper mandrel 9. By pressing down with the punch press, the upper stacked part 32 is shaped, the third rounded corner is reduced, and the top of the upper stacked part 32 is made flat. The diameter of the hollow cavity of the inner stacked part 3 and the distance from the top of the upper stacked part 32 to the end face of the shell 1 are adjusted to meet the process requirements, thereby forming the inner stacked part 3.

[0059] In step 304, reducing the third fillet is to improve the strength of the connection between the upper stacked part 32 and the upper housing 1. The top of the upper stacked part 32 is flat, which facilitates the installation of bearings and ensures that the bearings have sufficient support surface.

[0060] The dimensions of the flared section are precisely controlled through a shaping process to meet the process requirements for the central hole diameter of the inner stacked part 3, as well as the distance from the top surface of the inner stacked part 3 to the end face of the housing 1. After shaping, the inner diameter of the housing can meet the accuracy of ±0.02 mm, achieving the precision of machining, eliminating the need for secondary processing.

[0061] Preferred, such as Figure 8 As shown, step 4 includes: performing partial lateral stamping on the outer stacked material portion 2 to form an outer channel 4. Specifically, the aluminum alloy tube body processed in step 3 is placed in the lower die, and a mandrel is inserted into the aluminum alloy tube body. The diameter of the mandrel is equal to the inner diameter of the aluminum alloy tube body. The mandrel restricts the flow range of the aluminum alloy tube body material during subsequent lateral stamping. Through the lateral stamping forming method, the lateral force converted from the downward pressing of the lateral stamping punch on the outer stacked material portion 2 of the aluminum alloy tube body is used to laterally extrude the material of the outer stacked material portion 2, extruding the material of the outer stacked material portion 2 into the annular groove of the outer stacked material portion 2. The extruded part of the outer stacked material portion 2 forms the outer channel 4. The outer channel 4 divides the outer stacked material portion 2, and the bottom surface of the outer channel 4 is the surface of the shell 1. Multiple outer channels 4 can be provided. Let M outer channels 4 be provided, dividing the outer stacked material portion 2 into M parts, where M is an integer greater than 1.

[0062] In step 4, due to the obstruction of the mandrel, during the lateral stamping of the outer stack 2, the material corresponding to that portion of the outer stack 2 flows into the annular groove. The annular groove provides extra material accommodating space for forming the outer channel 4. In this method, the material originally located in the outer channel 4 is accommodated by the annular groove, preventing this material from flowing to the outer wall of the housing 1 and changing the outer diameter of the housing 1. After the lateral stamping of the outer channel 4, both the outer and inner diameters of the housing 1 remain unchanged.

[0063] Preferably, the method is implemented using a multi-station punch press, which includes a stacking station, a first necking station, a second necking station, a first forming station, a flaring station, a second forming station, and a side stamping station. During operation, a robotic arm transfers the die within the same punch press, stamping all stations simultaneously. The robotic arm moves the product to be stamped from one station to the next. The time to produce one of the housings using this method and punch press is in the order of seconds. In continuous operation, stamped products are continuously removed from the punch press, with the stamping process taking approximately 5 seconds.

[0064] The method of this invention solves the manufacturing problem of harmonic reducer motor housings for humanoid robots. It addresses the manufacturing precision issues, reduces costs, and improves production efficiency of aluminum alloy housings through stamping. This method combines stamping with necking, bulging, and shaping processes to achieve multi-station stamping, replacing traditional aluminum tube and machining processes, thereby reducing manufacturing costs. Compared to making aluminum tube blanks and then performing traditional machining, the method of this invention can reduce the manufacturing cost of a single housing by approximately 50%. The raw material consumption of the stamping solution is one-third that of traditional machining processes. Traditional machining takes approximately 5 minutes to process one housing. The method of this invention, through multi-station stamping, processes one housing in approximately 5 seconds, greatly improving manufacturing efficiency, ensuring more stable product quality, reducing the production cycle, and enabling mass production.

Claims

1. A method of press forming an aluminum alloy housing, characterized by, The shell is tubular, and comprises a shell body (1), an outer stacking part (2) outside the shell body (1), and an inner stacking part (3) in the inner cavity of the shell body (1), wherein the outer stacking part (2) is provided with an outer channel (4); the method comprises the following steps: Step 1: obtaining an aluminum alloy pipe body, the inner diameter of the aluminum alloy pipe body is equal to the inner diameter of the shell body of the formed aluminum alloy shell, and the outer diameter of the aluminum alloy pipe body is equal to the outer diameter of the shell body of the formed aluminum alloy shell; Step 2: using a stamping process to perform axial stacking of the aluminum alloy pipe body to the outer side of the pipe body to form an outer stacking part (2); Step 3: using a stamping process to perform axial stacking of the aluminum alloy pipe body to the inner cavity of the pipe body to form an inner stacking part (3); Step 4: performing local lateral stamping on the outer stacking part (2) to form an outer channel (4), thereby obtaining an aluminum alloy shell; The step 3 comprises: Step 301: using a stamping process to perform N times of necking on the inner side of the aluminum alloy pipe body; N is an integer, and N≥2, thereby forming a lower stacking part (31) with an arc-shaped end face; a first round corner is formed at the connection between the upper outer part of the lower stacking part (31) and the shell body (1), and a second round corner is formed at the connection between the lower inner part of the lower stacking part (31) and the shell body (1), and the second round corner is equal to the round corner at the connection between the lower inner part of the inner stacking part (3) and the shell body (1); Step 302: performing stamping shaping on the lower stacking part (31) to reduce the first round corner and change the shape of the lower stacking part (31), and the cross section of the lower stacking part (31) changes from an arc shape to an inclined straight line shape; Step 303: performing flaring on the upper part of the lower stacking part (31) of the aluminum alloy pipe body processed in step 302 to form an upper stacking part (32) between the lower stacking part (31) and the upper shell body (1), and a third round corner is formed between the upper inner part of the upper stacking part (32) and the upper shell body (1); the upper stacking part (32) and the lower stacking part (31) form the inner stacking part (3); Step 304: performing stamping shaping on the upper stacking part (32) to reduce the third round corner and make the top of the upper stacking part (32) a flat surface, so that the hollow cavity diameter of the inner stacking part (3) and the distance from the top of the upper stacking part (32) to the end face of the shell body (1) meet the process requirements, thereby obtaining the inner stacking part (3).

2. The method of press forming an aluminum alloy housing according to claim 1, characterized by, The inner diameter of the aluminum alloy pipe body is 50-55 mm, and the outer diameter is 56-60 mm.

3. The method of press forming an aluminum alloy housing shell of claim 1, wherein, The material of the aluminum alloy pipe body is aluminum alloy 6061-T6.

4. The method of press forming an aluminum alloy housing shell of claim 1, wherein, In step 2, an annular groove is formed on the inner side of the outer stacking part (2), and the vertical projection of the annular groove is located in the shell body (1).

5. The method of press forming an aluminum alloy housing shell of claim 1, wherein, In step 301, N times of necking is performed, and the necking ratio of each time is greater than that of the next time.

6. The method of press forming an aluminum alloy housing shell of claim 5, wherein, In step 301, N=2, the necking ratio of the first time is less than 10%, and the necking ratio of the second time is less than 8%.

7. The method of press forming an aluminum alloy housing shell of claim 4, wherein, The step 4 comprises: The aluminum alloy pipe body after step 3 processing is placed in the lower die, a core rod is inserted into the aluminum alloy pipe body, the diameter of the core rod is equal to the inner diameter of the aluminum alloy pipe body; through a side stamping forming mode, a partial material of the outer material stacking part (2) of the aluminum alloy pipe body is laterally extruded by a lateral force converted by a punch of the side stamping when the punch is pressed down by a punch press, the partial material of the outer material stacking part (2) is extruded into an annular groove of the outer material stacking part (2), and the extruded partial material of the outer material stacking part (2) forms an outer channel (4); the outer channel (4) separates the outer material stacking part (2), and a bottom surface of the outer channel (4) is a surface of the shell (1).

8. The method of press forming an aluminum alloy housing shell of claim 1, wherein, The method is realized by a multi-station punch press, the punch press is provided with a material stacking station, a first necking station, a second necking station, a first shaping station, an expanding station, a second shaping station and a side stamping station; a piece of the shell is prepared by the method and the punch press, and the time is in a second level.

9. The method of press forming an aluminum alloy housing shell of claim 1, wherein, The shell is used as a shell of a harmonic reducer.

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