Manufacturing mold of aluminum alloy motor shell and preparation method of aluminum alloy motor shell

Abstract

The invention discloses a manufacturing die of an aluminum alloy motor shell and a preparation method of the aluminum alloy motor shell, and the manufacturing die of the aluminum alloy motor shell comprises an upper die and a lower die matched with the upper die; the upper die comprises a plurality of flow dividing holes, a plurality of flow dividing cones and a die core, the flow dividing holes are annularly arranged along the periphery of the die core, the flow dividing cones surround the flow dividing holes, the flow dividing cones and the flow dividing holes are alternately arranged and used for preliminarily dividing metal flow from an extrusion ingot into several strands to flow to the flow dividing holes, and a first working belt is arranged on the die core. The lower die comprises a die hole matched with the die core and used for forming the wall thickness of the profile, a welding chamber and a second working belt, and the welding chamber is communicated with the flow dividing holes; and the second working belt is arranged at a discharge port of the welding chamber and is used for plastic deformation of metal and sizing of products. The integral motor shell profile integrated with the upper shell and the lower channel can be directly extruded at one time, and the motor shell profile has the advantages that the process is simplified, the cost is reduced, and the efficiency and the quality are improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy motor housing manufacturing technology, and in particular to a manufacturing mold and a method for manufacturing aluminum alloy motor housing. Background Technology

[0002] As a key structural component of motors, aluminum alloy motor housings not only need to provide support and protection but also often integrate functional structures such as cooling channels. With the development of motors towards higher power density and more efficient heat dissipation, the demand for housings with complex internal flow channels is increasing. Aluminum extrusion molding is an efficient method for manufacturing such long-shaft housing parts.

[0003] Existing aluminum alloy motor housings are mainly composed of an upper housing and a lower channel. Due to the complex internal channels of the aluminum alloy motor housing, traditional extrusion die designs often struggle to achieve one-time integral forming for complex, irregularly shaped hollow aluminum profiles, especially those with cross-sections containing both large closed cavities and small internal channels. This is because the die core (tongue core) structure inside the die is exceptionally complex and slender, making it prone to deformation, displacement, or even breakage during high-pressure, high-temperature extrusion, resulting in uneven product wall thickness, dimensional deviations, or die damage. Currently, the upper housing and lower channel are usually extruded separately, and then the two parts are welded and machined multiple times to complete the process. This method requires two extrusions and a friction stir welding process, resulting in high processing costs, a cumbersome production process, and low efficiency. In addition, the welding process is prone to introducing defects (such as incomplete penetration, surface grooves, and uneven microstructure), and welding deformation may lead to difficulties in subsequent machining or product deviations, affecting the overall yield. Welded joints may become weak points in structural reliability under long-term thermal cycling or vibration loads.

[0004] Therefore, how to provide a mold for one-time extrusion molding of aluminum alloy motor housings and a matching preparation method is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a manufacturing mold for aluminum alloy motor housing and a method for preparing aluminum alloy motor housing. It can directly extrude an integral motor housing profile integrating the upper shell and the lower channel in one step, which has the advantages of simplifying the process, reducing costs, and improving efficiency and quality.

[0006] The technical solution provided by this invention is as follows: A manufacturing mold for an aluminum alloy motor housing includes an upper mold and a lower mold that cooperates with it. The upper mold is in direct contact with the extruded ingot for diverting metal, and the lower mold is disposed at the discharge end of the upper mold for metal welding and final forming. The upper mold includes several flow-diverting holes, several flow-diverting cones, and a mold core. The mold core mates with the mold hole of the lower mold to form the shape of the internal cavity of the profile, and several of the flow diversion holes are arranged in a ring along the outer periphery of the mold core. The flow divider cones are arranged around and alternately with the flow divider holes to initially divide the metal flow from the extruded ingot into several streams directed to each flow divider hole. The mold core is provided with a working belt; The lower mold includes a mold hole that mates with the mold core to form the profile wall thickness, a welding chamber, and a working zone. The welding chamber is connected to the diversion hole to merge the multiple strands of metal that have been diverted and to re-weld the multiple strands of metal into a whole under high temperature and high pressure. The second working zone is located at the outlet of the welding chamber and is used for the plastic deformation of metal and the sizing of the product.

[0007] Preferably, a plurality of the diverting cones are provided with receiving members on their inner sides, and the downward extensions of the ends of the plurality of diverting cones are respectively connected to the receiving members. The receiving members can be mesh-like, cross-shaped, or other geometric shapes that can connect the diverting cones. The receiving members are preferably annular structures.

[0008] Preferably, the mold core comprises three parts: inner, middle, and outer. The inner layer is located on the innermost side and is used for forming the main cavity of the upper housing of the motor housing. The middle layer structure is arranged in a ring around the outermost structure to form water channel holes on the motor housing. The outer layer structure is located on the outside of the annular structure to form the lower channel on the motor housing; The working belt is provided on the outer periphery of the inner, middle and outer parts of the mold core structure.

[0009] Preferably, the second working strip is directly machined on the lower mold.

[0010] Preferably, the lower mold has a support pad at its end to support the entire mold assembly.

[0011] Preferably, the welding chamber is provided with several flow-blocking platforms for adjusting the metal flow rate.

[0012] Preferably, the number of the flow divider cones is not less than six, such as six or eight, and preferably nine. The flow divider cones are evenly distributed along the circumference. The flow divider cones can achieve uniform flow division and are connected and reinforced in the center by a connecting member to support the internal mold core. The number of diversion holes and welding chambers are consistent with the number of diversion cones and are provided in a matching manner.

[0013] A method for manufacturing an aluminum alloy motor housing, using the aforementioned mold for manufacturing aluminum alloy motor housings, includes the following steps: S1. Extrusion: The cast rod heated to 460-480℃ is placed into the preheated extrusion cylinder and extrusion begins. The extrusion speed is 2.0-2.4 mm / s. Under the action of the extrusion cylinder, the cast rod moves to the preheated aluminum alloy motor housing manufacturing mold for forming. S2. Quenching: The profiles coming out of the mold for manufacturing aluminum alloy motor housings are air-cooled and quenched. S3, Interruption: Cutting continuous profiles into equal-length profiles of a certain length; S4. Stretching: Fix both ends of the equal-length profile and stretch it by 1% to 2%; S5. Sawing and framing: Remove waste material generated from stretching and squeezing at the beginning and end to form qualified profiles that meet the requirements; S6. Aging: Keep qualified profiles at 180-200℃ for 4-6 hours; S7. Precision cutting and finishing: After aging, qualified profiles are precision cut to the specified dimensions and then finished to obtain the required aluminum alloy motor housing.

[0014] Preferably, in step S1, the extrusion cylinder is preheated to 440-410°C, and the mold for manufacturing the aluminum alloy motor housing is preheated to 510-530°C.

[0015] Preferably, in step S5, 1300-1500 mm of waste material from the head is removed, and 900-1200 mm of waste material from the tail is removed.

[0016] The present invention has the following advantages over the prior art: This application, through a rational structural design of the upper and lower dies, enables the molding of aluminum alloy motor housings using a single die and a single extrusion operation. This eliminates the need for a separate die, an additional extrusion operation, and the entire friction stir welding process, directly and significantly reducing equipment depreciation, energy consumption, and labor costs. Simultaneously, it integrates a lengthy, multi-step process into a highly efficient single extrusion molding, shortening the production cycle and reducing space and manpower requirements. Furthermore, products manufactured using the die developed in this application are free from welding defects and deformation risks, exhibiting higher dimensional accuracy, more uniform internal structure, and superior overall mechanical properties and reliability. In conclusion, this invention solves complex structural molding problems through innovative die design and process control, demonstrating high technological added value. Attached Figure Description

[0017] 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 recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the manufacturing mold for the aluminum alloy motor housing in an embodiment of the present invention; Figure 2 This is a schematic diagram of the upper mold in an embodiment of the present invention; Figure 3 This is a schematic diagram of the lower mold structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the aluminum alloy motor housing prepared in the embodiment of the present invention.

[0019] Figure label: 1. Upper mold; 11. Diverter hole; 12. Diverter cone; 13. Mold core; 131. Inner layer structure; 132. Middle layer structure; 133. Outer layer structure; 14. Working zone one; 15. Receiving component; 2. Lower mold; 21. Mold hole; 22. Welding chamber; 23. Working zone two; 24. Flow-blocking platform; 3. Main cavity of upper shell; 4. Water channel hole; 5. Lower channel. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] like Figures 1-4 As shown, this embodiment of the invention provides a manufacturing mold for an aluminum alloy motor housing, including an upper mold 1 and a lower mold 2 that cooperates with it. The lower end face of the upper mold 1 and the upper end face of the lower mold 2 are precisely positioned and locked by a stop or a pin. The upper mold 1 directly contacts the extruded ingot for diverting metal. The lower mold 2 is set at the discharge end of the upper mold 1 for metal welding and final forming. The upper mold 1 includes a plurality of diversion holes 11, a plurality of diversion cones 12 and a mold core 13. The mold core 13 cooperates with the mold hole 21 of the lower mold 2 to form the shape of the internal cavity of the profile. The plurality of diversion holes 11 are arranged in a ring along the outer periphery of the mold core 13. The die is configured such that a flow divider cone 12 surrounds and alternates with the flow divider hole 11 to initially divide the metal flow from the extrusion ingot into several streams flowing to each flow divider hole. The die core 13 is provided with a working band 14. The lower die 2 includes a die hole 21 that cooperates with the die core 13 to form the profile wall thickness, a welding chamber 22, and a working band 23. The welding chamber 22 is connected to the flow divider hole 11 to merge the multiple streams of metal that have been divided and to re-weld the multiple streams of metal into a whole under high temperature and high pressure. The working band 23 is located at the outlet of the welding chamber 22 for plastic deformation of the metal and sizing of the product.

[0022] In this embodiment, the reasonable structural design of the upper mold 1 and the lower mold 2 makes the metal flow controllable and more uniform throughout the process, effectively reducing defects such as profile warping, twisting, tail shrinkage, and burrs, and improving forming accuracy and surface quality; the mold has strong overall stability, with no local deformation during extrusion, reducing the frequency of mold adjustment and improving continuous production efficiency; no post-welding repair is required, reducing mold maintenance costs and adapting to the needs of large-volume, highly consistent profile production.

[0023] In this embodiment, both the working belt 14 and the flow divider cone 12 in the upper mold 1 can be designed as an integrated structure. The integrated structure allows for better coordination between the flow divider cone 12 and the speed control of the working belt 14, significantly improving the extrusion yield. At the same time, the integrated working belt 14 has a uniform thickness, a precise and stepless transition with the mold cavity, and hardened polishing on key parts such as sharp corners / thin walls.

[0024] In this embodiment, the mold core 13 and the flow divider cone 12 are integrally structured or connected separately to the flow divider cone 12 by threads. The tip of the mold core 13 must maintain precise coaxiality and clearance with the mold hole 21 of the lower mold.

[0025] In this embodiment, there are no seams in the upper mold 1, and the overall rigidity of the diversion cone 12 and working belt 14 is high, which improves the upper mold's resistance to extrusion and wear, and greatly increases its service life.

[0026] In this embodiment, several diversion cones 12 are provided with receiving members 15 on their inner sides. The downward extensions of the ends of several diversion cones 12 are respectively connected to the receiving members 15. The receiving members 15 can increase the strength of the diversion cones 12 and prevent the diversion cones 12 from breaking under pressure.

[0027] In this embodiment, the mold core 13 includes three parts: inner, middle, and outer. The inner layer structure 131 is located on the innermost side for forming the main cavity 3 of the motor housing. The middle layer structure 132 is located on the outer periphery of the innermost structure in a ring shape for forming the water channel hole 4 on the motor housing. The outer layer structure 133 is located on the outer side of the ring structure for forming the lower channel 5 on the motor housing. The working belt 14 is provided on the outer periphery of the inner, middle, and outer parts of the mold core 13.

[0028] In this embodiment, there are nine flow divider cones 12, which are evenly distributed along the circumference (average distribution at 40°). The number of flow divider holes 11 and welding chambers 22 are consistent with the number of flow divider cones 12 and are matched.

[0029] In this embodiment, the working principle of the welding chamber 22 is as follows: The welding chamber 22 is a place where the hot soft aluminum material that has been "split" and diverted is pressed and bonded back into a whole piece in a closed small space. It is the key to making hollow aluminum profiles. Because to make hollow, the aluminum material has to go around the mold core in the mold. It can only be split into several streams and flow through, and then bonded back in the welding chamber. Otherwise, a hollow shape cannot be produced.

[0030] In this embodiment, both working belt 14 and working belt 23 are adapted to the width of the metal flow characteristics of different parts of the profile, with wider working belts in fast-flowing areas and narrower working belts in slow-flowing areas. The core function of both working belts in the mold of this embodiment is to add frictional resistance to the flowing hot, soft aluminum material. The width of the working belt directly determines the magnitude of the resistance; the wider the belt, the longer the friction surface on which the aluminum material rubs against, resulting in greater resistance and slower flow; the narrower the belt, the shorter the friction surface, the lower the resistance, and faster flow. "Widening the fast-flowing area and narrowing the slow-flowing area" essentially means adjusting the resistance of each part using the width of the working belt, forcing the aluminum material from all parts of the profile to flow out of the mold opening at the same time. This avoids uneven flow of aluminum material, which can cause the extruded profile to be distorted, have uneven wall thickness, or deform in shape, ensuring a uniform output. In addition, working belts 14 and 23 are also used to precisely control the profile dimensions, with an accuracy of 0.1mm.

[0031] In this embodiment, in addition to balancing the flow rate by adjusting the width of working belt 14 and working belt 23, the flow rate can also be adjusted by setting a "flow-promoting angle" or "obstruction angle" at the cavity of the lower mold 2 (welding chamber 22 or mold hole 21 inlet), or by making differentiated designs in the size of the diversion hole, so as to achieve a similar balanced flow effect.

[0032] In this embodiment, the working strip 23 is directly processed on the lower mold 2, and the working strip 23 and the lower mold 2 are an integral structure.

[0033] In this embodiment, the lower die 2 is provided with a support pad (not shown in the figure) at its end to support the entire die assembly and prevent the die from deforming or being damaged under high pressure. The support pad is usually very hard but does not directly participate in the molding process. Behind the support pad is the die base of the extruder.

[0034] In this embodiment, several flow-blocking platforms 24 are provided at the welding chamber 22. The functions of the flow-blocking platforms 24 are as follows: 1. Balance flow rate: block and change the direction of metal flow, reduce the flow rate in areas prone to excessive speed, adapt to uneven wall thickness / complex cross sections, avoid waves, twisting, and dimensional deviations, and improve surface quality and dimensional accuracy; 2. Optimize welding: prolong the residence and contact of metal in the welding chamber, increase welding pressure and temperature, allow the metal to fuse more fully after diversion, reduce weld line defects, and enhance profile strength; 3. Stabilize forming: make the metal flow more stable, reduce vibration marks, assist in initial shaping and dimensional correction, and ensure the straightness and integrity of the profile; 4. Protect the mold: disperse the force on the mold core, reduce local wear and fatigue, and extend the service life of the mold. The number and position of the flow-blocking platforms 24 can be reasonably set according to actual needs. In this embodiment, there are four flow-blocking platforms 24, two of which are located at the position for forming the lower channel 5, the third flow-blocking platform 24 is set close to the above two flow-blocking platforms 24, and the last flow-blocking platform 24 is set apart from the third welding chamber 22 by two welding chambers 22.

[0035] A method for manufacturing an aluminum alloy motor housing, using the aforementioned aluminum alloy motor housing manufacturing mold, includes the following steps: S1. Extrusion: The cast rod heated to 460-480℃ is placed into the preheated extrusion cylinder (75MN extruder) and extrusion begins. The extrusion speed is 2.2mm / s and the breakthrough pressure is 270bar. The cast rod (cast rod alloy 6063) moves under the action of the extrusion cylinder to the preheated aluminum alloy motor housing manufacturing mold for forming. S2. Quenching: The profiles coming out of the mold for manufacturing aluminum alloy motor housings are subjected to air-cooled quenching (the profiles are rapidly cooled by air cooling). S3. Interruption: Cut the continuous profile into equal-length profiles of a certain length (because extrusion is continuous, two cast rods will join together during extrusion, so they need to be cut into separate sections). S4. Stretching: Fix both ends of the equal-length profile and stretch it by 1% to 2%. Stretching can remove the internal stress generated by quenching. Since quenching will cause the profile to bend, stretching can also straighten the profile. S5. Sawing and framing: Remove waste material generated from stretching and squeezing at the beginning and end to form qualified profiles that meet the requirements; S6. Aging: Qualified profiles are kept at 180-200℃ for 4-6 hours to improve mechanical properties and increase profile hardness; S7. Precision cutting and finishing: The qualified profiles after aging are precision cut to the specified size (e.g., length of 3000mm), and then finished to obtain the required aluminum alloy motor housing.

[0036] In this embodiment, because the extrusion process generates deformation heat, the exit temperature will be higher than the bar temperature. The exit temperature is affected by both the bar temperature and the extrusion speed. The required exit temperature is 500-550℃. Below this temperature range, poor quenching and low performance will occur; above this temperature range, the profile will crack. Therefore, the required extrusion speed is 2.0-2.4 mm / s, preferably 2.2 mm / s. Additionally, the breakthrough pressure needs to be considered. As shown in Table 1, when the breakthrough pressure exceeds 280 bar, the die's capacity decreases, damaging the die's life and reducing the amount of aluminum that can pass through it. Therefore, the breakthrough pressure in the extrusion process is generally required to be less than 280 bar.

[0037] Table 1 Extrusion Process Parameters

[0038] In this embodiment, in step S1, the extrusion cylinder is preheated to 440-410°C, and the mold for manufacturing the aluminum alloy motor housing is preheated to 510-530°C.

[0039] In this embodiment, in step S5, 1300-1500mm of waste material from the head is removed, and 900-1200mm of waste material from the tail is removed.

[0040] The aluminum alloy motor housing preparation method of this embodiment uses a mold with a structure including a flow divider 11, a flow divider cone 12, and a welding chamber 22. It optimizes key parameters such as extrusion temperature and speed so that the aluminum flow can be smoothly filled and welded in the mold to form an integral profile with a complex internal cavity (upper shell main cavity 3 and lower channel 5). The finished product can be obtained by conventional sawing and a small amount of machining. The process is simple and controllable.

[0041] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A mold for manufacturing an aluminum alloy motor case comprising an upper mold and a lower mold to be fitted therewith, characterized in that, The upper die is directly contacted with the extrusion ingot for distributing the metal, and the lower die is arranged at the discharging end of the upper die for metal welding and final forming; The upper die comprises a plurality of distribution holes, a plurality of distribution cones and a die core, The die core cooperates with the die hole of the lower die for forming the shape of the internal cavity of the profile, and the plurality of distribution holes are arranged in a ring along the outer periphery of the die core, The distribution cone is arranged around the distribution hole and alternately with the distribution hole for preliminarily dividing the metal flow from the extrusion ingot into several flows to each distribution hole, The die core is provided with a working belt one; The lower die comprises a die hole cooperating with the die core for forming the wall thickness of the profile, a welding chamber and a working belt two, The welding chamber communicates with the distribution hole for converging the multiple metal flows distributed and re-welding the multiple metal flows into a whole under high temperature and high pressure; The working belt two is arranged at the discharging port of the welding chamber for plastic deformation of the metal and sizing of the product.

2. The manufacturing die for an aluminum alloy motor case according to claim 1, characterized by, The plurality of distribution cones are provided with receiving members on the inner side, and the plurality of distribution cone ends extend downward and are connected with the receiving members respectively.

3. The manufacturing die for an aluminum alloy motor case according to claim 1, characterized by, The die core comprises inner, middle and outer three-part structures, the inner layer structure is arranged at the innermost side for forming the main cavity of the upper shell of the motor shell, The middle layer structure is arranged at the outer periphery of the innermost structure in a ring for forming the water channel hole on the motor shell; The outer layer structure is arranged at the outer side of the ring structure for forming the lower channel on the motor shell; The working belt one is arranged on the outer periphery of the inner, middle and outer three-part structures of the die core.

4. The manufacturing die for an aluminum alloy motor case according to claim 1, characterized by The working belt two is directly machined on the lower die.

5. The manufacturing die for an aluminum alloy motor case according to Claim 1, characterized by The lower die is provided with a support pad at the end for supporting the entire die set.

6. The manufacturing die for an aluminum alloy motor case according to claim 1, characterized by The welding chamber is provided with a plurality of resistance tables for adjusting the flow rate of the metal.

7. The manufacturing die for an aluminum alloy motor case according to Claim 1, characterized by The number of the distribution cones is not less than six, and the distribution cones are uniformly distributed along the circumference; The number of the distribution holes and the welding chamber is consistent with the number of the distribution cones and is arranged in a matched manner.

8. A method of producing an aluminum alloy motor case, characterized by, The manufacturing die of the aluminum alloy motor shell is manufactured according to any one of claims 1-7, and comprises the following operation steps: S1, extrusion: the cast bar heated to 460-480℃ is put into the preheated extrusion cylinder, and the extrusion is started, the extrusion speed is 2.0-2.4mm / s, and the cast bar is moved to the preheated aluminum alloy motor shell manufacturing die under the action of the extrusion cylinder for forming; S2, quenching: the profile coming out of the outlet of the aluminum alloy motor shell manufacturing die is air-cooled and quenched; S3, interruption: the continuous profile is sawn and interrupted into a certain length of equal-length profile; S4, stretching: the equal-length profile is fixed at both ends and stretched, and the stretching amount is 1%-2%; S5, sawing and framing: the waste material generated by stretching and extrusion at the head and tail is removed to form a qualified profile meeting the requirements; S6, aging: the qualified profile is aged at 180-200℃ for 4-6 hours; S7, fine cutting and finishing: the qualified profile after aging is fine cut to the specified size, and after later finishing, the required aluminum alloy motor shell is obtained.

9. The method of making an aluminum alloy motorcase of claim 8, wherein, In the step S1, the preheating temperature of the extrusion cylinder is 440-410℃, and the preheating temperature of the aluminum alloy motor shell manufacturing die is 510-530℃.

10. The method of making an aluminum alloy motorcase of claim 8, wherein, In the step S5, the waste material of 1300-1500mm at the head is removed, and the waste material of 900-1200mm at the tail is removed.

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