An integrated stamping forming die for a drone brushless motor shell

Abstract

This invention discloses an integrated stamping die for a brushless motor housing of a drone, belonging to the field of stamping die technology. It includes upper and lower dies and a side-pressing mechanism. The upper die adopts a composite punch structure, including a floating outer punch and a main inner punch. Through the relay motion of the two within a single stroke, two-stage deep drawing of the sheet metal is achieved. The lower die adopts a floating core die structure, which works in conjunction with the composite punch to complete the deep drawing. At the end of the deep drawing stroke, the die completes the punching of the air inlet at the top of the motor housing through a fixed punch; multiple side-pressing forming cutters are driven by a ring-driven wedge to complete the punching of the ventilation louvers on the side wall of the housing; and the edge waste is removed through the cooperation of the inner punch cutting edge and the lower die. This invention integrates multiple processes such as deep drawing, punching, side pressing, and edge trimming into one, significantly improving production efficiency and product precision.

Description

Technical Field

[0001] This invention belongs to the field of stamping die technology. Specifically, this invention relates to a stamping die that can integrally form a thin-walled shell of a brushless motor for a drone with complex three-dimensional features within one stamping stroke. Background Technology

[0002] As an important branch of modern aviation technology, the performance of unmanned aerial vehicles (UAVs) largely depends on the efficiency and reliability of their power systems. External rotor brushless DC motors (such as...) Figure 20 , 21 (As shown) Due to its high power density, high efficiency, and long lifespan, it has become the preferred choice for UAV power systems. The outer rotor housing of this motor is not only a rotating component that supports the permanent magnets and transmits torque, but more importantly, it plays a core role in the entire motor's heat dissipation system. To achieve extreme lightweighting and excellent heat dissipation performance, the housing is typically designed as a thin-walled, deep-cavity structure, with an integrally formed end-face air inlet 38 at the top for drawing in cool air and integrally formed ventilation louvers 37 on the side walls for expelling hot air.

[0003] This type of precision shell integrates three-dimensional features such as thin walls, deep cavities, a sloping top, a porous system, and sidewalls (e.g., Figure 15 As shown in the figure, the mainstream manufacturing methods in the industry currently face significant technological bottlenecks:

[0004] CNC machining involves cutting solid metal bars through multiple processes such as turning and milling. The advantage of this method is its ability to achieve extremely high dimensional accuracy and complex geometries. However, its disadvantages are also significant: firstly, the machining cycle time is measured in minutes, resulting in extremely low production efficiency; secondly, over 60% of the raw material is cut into scrap, causing enormous material waste; and finally, the unit production cost is high, completely failing to meet the stringent cost control requirements of the consumer and industrial drone markets.

[0005] Multi-stage stamping: This is a step-by-step forming method that typically requires multiple independent dies and stamping presses to sequentially complete processes such as blanking, initial drawing, secondary drawing, top punching, and side wall punching. Transfer between processes relies on manual labor or robots. While this method improves efficiency and cost compared to CNC machining, it still has several inherent drawbacks: First, the production line is lengthy, requiring significant equipment investment and occupying substantial factory space; second, cumulative errors inevitably occur during multiple transfers and repositioning of the workpiece, making it difficult to guarantee the coaxiality, wall thickness uniformity, and hole position accuracy of the final product.

[0006] In summary, existing technologies cannot achieve an ideal balance between efficiency, cost, precision, and yield. Therefore, there is a need for a method that can integrally mold such complex thin-walled motor housings in a compact, efficient, and precise manner. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an integrated stamping mold for the shell of a brushless motor for a drone. The aim is to achieve the entire manufacturing process from flat sheet metal to complex finished shell through a single station and single stroke by using a highly integrated structure.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] An integrated stamping die for a brushless motor housing of a drone includes a lower die fixed on a base and an upper die that can move up and down relative to the lower die along guide pillars. The overall structure of the invention is built on a base, and the upper die can be precisely guided by multiple guide pillars. The upper die is a composite punch structure, including an outer punch and an inner punch coaxially arranged, both of which are elastically connected to the upper die through elastic elements. The lower die includes a fixed lower die and a floating core die that can float up and down within the lower die. In one stamping stroke, the outer and inner punches first descend together, cooperating with the lower die to perform the first stage of drawing the sheet metal. Subsequently, the outer punch stops descending and acts as a pressure material on the flange edge of the workpiece, while the inner punch continues to descend, pushing the floating core die to sink, performing the second stage of drawing the workpiece.

[0010] The upper module also includes at least one punch fixed to the bottom surface of the upper template. The punch passes through the inner punch and is used to punch a hole in the top of the motor housing at the end of the stamping stroke.

[0011] Furthermore, the punch includes a main punch and multiple peripheral punches arranged in a circular array; the floating core mold has a central blanking channel corresponding to the main punch and a core mold blanking channel corresponding to the peripheral punches.

[0012] The invention also includes a plurality of radially movable side-press forming blades, and an annular drive wedge fixed on the upper template for driving the side-press forming blades to move radially; after the second stage of deep drawing is completed, the annular drive wedge drives the side-press forming blades to move inward to stamp the side wall of the motor housing.

[0013] In addition, the inner punch is provided with a cutting edge; after the second stage of deep drawing is completed, the cutting edge of the inner punch contacts and engages with the lower die to remove the edge waste of the workpiece.

[0014] The inner punch of the present invention has an inverted frustum at its end, and the end face of the outer punch is an annular conical surface with an angle equal to that of the frustum; the top edge of the lower die is a first-order conical surface, and the top surface of the floating core mold is a recessed second-order conical surface with the same angle; in the initial state, the conical surfaces of the upper and lower dies are aligned to form matching upper and lower frustum contours for forming the top surface of the oblique frustum of the motor housing.

[0015] Furthermore, the inner punch has a raised ring platform on its side wall, and the outer punch is hung on the top surface of the ring platform through the shoulder structure of its inner wall. The bottom surface of the ring platform is a cutting edge.

[0016] The floating core mold of the present invention is elastically connected to the base through a core mold support spring at its bottom; the lower die is provided with a core mold limiting pin for limiting the upward position of the floating core mold.

[0017] The inner punch of the present invention has a clearance groove on its outer peripheral wall to provide clearance space for the side-pressure forming knife when it moves inward.

[0018] The invention also includes a pressure ring that is elastically connected to the upper template by a pressure ring spring. The pressure ring is used to initially press the outer edge of the sheet metal during the initial stamping stage.

[0019] The core of this mold consists of an upper mold assembly and a lower mold assembly. The upper mold assembly is mounted on the bottom surface of the upper template, and its core is an upper die unit. This upper die unit adopts a composite punch structure, consisting of an outer punch and an inner punch arranged coaxially. The outer punch is elastically connected to the upper template through an outer punch compression spring, and the inner punch is elastically connected to the upper template through an inner punch compression spring. Through the composite structure with double elastic connections, "two-stage deep drawing" can be achieved. In addition, the upper mold assembly also includes a main punch and a peripheral punch for top punching at the end of the stamping stroke; an annular drive wedge for driving lateral forming; and a pressure ring for initial material clamping in the initial stage of stamping.

[0020] The lower mold assembly is fixed to the base, with the lower mold unit at its core. This lower mold unit employs a composite die structure, consisting of a fixed lower die and a floating core mold that can float axially up and down within it. The floating core mold is supported upwards by a core mold support spring at the bottom. Furthermore, multiple radially movable side-pressure forming blades are arranged radially around the lower die.

[0021] The working principle of this invention lies in the fact that, through the design of the elastic coefficient, stroke, and triggering timing of the linkage mechanism of the aforementioned moving parts, a simple vertical reciprocating motion of the punch press is decomposed into a complex, orderly, and interlocking sequence of internal forming actions:

[0022] In a complete stamping stroke, the outer and inner punches initially work as a single unit, cooperating with the lower die to perform the first stage of shallow drawing of the sheet metal. As the stroke deepens, the outer punch encounters resistance and stops descending, instead acting as a secondary pressure point on the flange edge of the workpiece, while the inner punch continues its powerful downward movement, pushing the floating mandrel to sink synchronously, thus performing the second stage of deep drawing. At the end of the stroke, near the completion of deep drawing, the die, through a linkage mechanism, simultaneously triggers top punching, sidewall punching, and edge scrap removal.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. Improved Production Efficiency: This invention integrates the manufacturing process, which traditionally requires multiple independent steps (two deep drawing processes, punching, side punching, and trimming), into a single mold and a single stamping stroke. This shortens the production cycle and improves production efficiency.

[0025] 2. Reasonable process: The "composite two-stage deep drawing" effectively avoids the fatal defects such as wrinkling and cracking that are common in one-time deep drawing of thin-walled materials by using the method of "shallow drawing + secondary pressing + deep drawing", which greatly improves the yield.

[0026] 3. Improved Product Precision: Since all dimensions and geometric tolerances are formed in a single clamping and positioning process, the cumulative errors caused by multiple processes and repeated positioning are fundamentally eliminated. This ensures that each motor housing has extremely high coaxiality, uniform wall thickness, and precise relative positions of the top and side wall holes, providing a benchmark for subsequent motor assembly and dynamic balancing.

[0027] 4. Improved economic efficiency: Replacing multiple sets of molds and equipment on a traditional production line with a single composite mold reduces mold development and maintenance costs. Simultaneously, the reduction in production floor space promotes the development of the drone motor industry. Attached Figure Description

[0028] Figure 1 This is one of the overall structural schematic diagrams of the present invention;

[0029] Figure 2 This is the second schematic diagram of the overall structure of the present invention;

[0030] Figure 3 This is a longitudinal sectional view of the present invention;

[0031] Figure 4 yes Figure 3 A magnified view of part A in the middle;

[0032] Figure 5 This is a schematic diagram of the sheet metal being placed onto the lower module;

[0033] Figure 6 This is a schematic diagram of the board material;

[0034] Figure 7 This is one of the schematic diagrams of the molding process (the pressure ring presses down on the sheet material).

[0035] Figure 8 This is the second schematic diagram of the molding process (the upper module presses the sheet into the lower module).

[0036] Figure 9 This is a schematic diagram of the first-stage molded product;

[0037] Figure 10 This is the third schematic diagram of the molding process (the inner punch continues to press down to further press and stretch the first-stage molded product).

[0038] Figure 11 This is a schematic diagram of the second-stage molded product;

[0039] Figure 12 This is the fourth schematic diagram of the molding process (the inner punch is pressed down into place).

[0040] Figure 13 This is another longitudinal section of the fourth schematic diagram of the molding process;

[0041] Figure 14 This is the fifth schematic diagram of the molding process (the upper mold resets, the floating core mold ejects the finished product from the lower mold, and the edge waste is not shown).

[0042] Figure 15 This is a schematic diagram of the finished motor housing;

[0043] Figure 16 This is a cross-sectional view of the present invention;

[0044] Figure 17 This is one of the structural schematic diagrams of the inner punch;

[0045] Figure 18 This is the second schematic diagram of the inner punch structure;

[0046] Figure 19 This is a schematic diagram of the outer punch structure;

[0047] Figure 20 This is one of the schematic diagrams of a brushless motor structure using the motor housing of the present invention;

[0048] Figure 21 This is the second schematic diagram of a brushless motor structure using the motor housing of this invention.

[0049] In the diagram: 1. Upper template; 2. Upper module; 3. Guide pillar; 4. Lower module; 5. Base; 6. Side forming blade; 7. End bevel; 8. Annular drive wedge; 9. Support pillar; 10. Pressure ring guide pillar; 11. Pressure ring spring; 12. Pressure ring; 13. Central blanking hole; 14. Outer blanking hole; 15. Outer punch; 16. Inner punch; 17. Main punch pillar; 18. Outer punch pillar; 19. Inner punch compression spring; 20. Outer punch guide pillar; 21. Outer punch compression spring; 22. 23. Core mold limiting pin; 24. First-order conical surface; 25. Second-order conical surface; 26. Floating core mold; 27. Core mold support; 28. Core mold support spring; 29. ​​Central blanking channel; 30. Sheet metal; 31. First-stage molded product; 32. Second-stage molded product; 33. Finished product; 34. Core mold blanking channel; 35. Support blanking channel; 36. Base blanking channel; 37. Ventilation louvers; 38. End face air inlet; 39. Ring platform; 40. Relief groove; 41. Vent hole. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] The description of the present invention is merely a structural or even functional description of the embodiments, and the scope of the present invention is not limited by the embodiments described herein.

[0052] like Figures 1-19 As shown, this embodiment is achieved through the following technical solution:

[0053] I. Overall Structure of the Mold

[0054] Reference Figures 1 to 4 The integrated stamping die of the present invention is mainly composed of an upper die assembly and a lower die assembly.

[0055] The entire mold is referenced by a fixed base 5. Four high-rigidity guide pillars 3 are vertically mounted at the four corners of the base 5, providing precise guidance for the movement of the upper mold assembly. The upper mold plate 1 slides with the guide pillars 3 and serves as the power input end for the entire mold.

[0056] Upper mold assembly, including:

[0057] Upper module 2: Employs a composite punch structure, consisting of an inner punch 16 and a coaxially fitted outer punch 15. (Example...) Figures 17-19As shown, a raised ring 39 is machined in the middle of the side wall of the inner punch 16, while a matching shoulder is machined on the inner wall of the outer punch 15. The shoulder is used to mount the punch 39 on its top surface, allowing axial relative movement between the two. The inner punch 16 and the outer punch 15 are elastically connected to the upper template 1 via their respective inner punch compression springs 19 and outer punch compression springs 21. The outer punch 15 also has an outer punch guide post 20 to ensure smooth movement, and a vent hole 41 is provided to balance the air pressure generated inside the outer punch 15 during movement.

[0058] The punching assembly consists of a main punch 17 located at the center of the die and multiple peripheral punches 18 arranged in a circumferential array. It is rigidly fixed to the bottom surface of the upper die plate 1 and passes through pre-drilled channels inside the inner punch 16. The stepped structure of the main punch 17 serves to suspend the inner punch 16 and prevent it from falling off in the initial state.

[0059] Side-pressure drive mechanism: The annular drive wedge 8 is rigidly fixed to the upper template 1 by multiple support columns 9. The inner circumference of the annular drive wedge 8 is machined into a conical surface to drive the side-pressure mechanism of the lower mold.

[0060] Preliminary pressing mechanism: The pressing ring 12 is elastically suspended below the upper template 1 by the pressing ring guide post 10 and the pressing ring spring 11.

[0061] The lower mold assembly is structurally compatible with the upper mold assembly, including:

[0062] Lower mold assembly 4: Adopts a composite die structure, consisting of a lower die 22 fixed to the base 5 and a floating core mold 26 that can float up and down within the central cylindrical cavity of the lower die 22. (Example) Figure 3 As shown, the bottom of the floating core mold 26 has an integrated cylindrical guide structure that passes through the fixed core mold support 27 and base 5 below, and is supported upward by the core mold support spring 28 coiled on it. The core mold limiting pin 23, which is horizontally inserted from the side wall of the lower die 22, passes into the groove on the side of the floating core mold 26, which can limit the highest floating position of the floating core mold 26. In order to form the truncated cone shape of the top of the motor housing, the top edge of the lower die 22 is machined with a first-order conical surface 24, and the top surface of the floating core mold 26 is machined with a matching recessed second-order conical surface 25.

[0063] Side-pressure forming mechanism: Multiple side-pressure forming blades 6 are mounted in radially arranged guide grooves around the lower die 22, allowing them to move horizontally in the radial direction. For example... Figure 16 As shown, the cutting head of each side-press forming cutter 6 is used to punch ventilation louver holes 37, and its outer end is machined with an end bevel 7 that matches the annular drive wedge 8.

[0064] Waste discharge structure: In order to discharge the waste generated by the top punch smoothly, the floating core mold 26 is provided with a central discharge channel 29 and a core mold discharge channel 34. The core mold support 27 and the base 5 below are also provided with support discharge channels 35 and base discharge channels 36, which together form a through central discharge hole 13 and an outer discharge hole (14).

[0065] The working process of this invention:

[0066] Step 1: Material preparation and initial pressing ( Figure 5 , Figure 6 , Figure 7 )

[0067] Before the stamping begins, the upper die 1 is at the top dead center position. The sheet metal 30 is placed on the top surface of the lower die 4. The press is started, and the upper die 1 begins to descend. The first part to contact the sheet metal 30 is the pressure ring 12, which is supported by the pressure ring spring 11. It presses the outer edge of the sheet metal 30 with a small pressure, which plays a role in initial positioning and preventing wrinkling during subsequent deep drawing.

[0068] Step Two: First Stage Deepening ( Figure 8 , Figure 9 )

[0069] The upper die plate 1 continues to descend. At this point, the end face of the composite punch, which consists of the outer punch 15 and the inner punch 16 and has a larger diameter, contacts the sheet metal. Under the strong pressure of the punch press, the sheet metal is pressed into the die cavity formed by the lower die 22 and the floating core die 26. Since the floating core die 26 is still in its highest position at this time, the drawing depth is relatively shallow. This process forms the first-stage cup-shaped product 31. This process is a shallow drawing with a small drawing ratio, and the material deformation is mild, preparing for subsequent deep drawing.

[0070] Step 3: Second stage of deep drawing ( Figure 10 , Figure 11 )

[0071] As the upper die 1 continues to descend, the bottom of the outer punch 15 contacts the hard stepped surface of the lower die 22, and its downward movement is hindered. At this time, the outer punch spring 21 begins to be compressed, and the stopped outer punch 15 changes its role to become a secondary pressure ring, pressing down on the flange edge of the first-stage molded product 31.

[0072] Meanwhile, driven by the press, the inner punch 16 continues to descend against the elastic force of the lower mandrel support spring 28 (the elastic coefficient of the inner punch spring is much greater than that of the mandrel support spring). This pushes the floating mandrel 26 downwards synchronously until its bottom contacts the fixed mandrel support 27. During this process, the bowl-shaped molded product is drawn a second time based on the smaller diameter of the inner punch 16, ultimately forming a cylindrical second-stage molded product 32 with the designed depth.

[0073] Step 4: Integration and Molding ( Figure 12 , Figure 13 )

[0074] At the end of the stroke when the inner punch 16 presses the floating core mold 26 onto the core mold support 27, almost at the same instant, other preset forming functions are triggered simultaneously:

[0075] Sidewall stamping: At this time, the annular drive wedge 8 fixed on the upper template 1 also descends to the predetermined working position. Its conical working surface contacts the end inclined surface 7 of all the side-pressure forming blades 6 and generates relative sliding, decomposing the vertical movement force of the upper template into a powerful horizontal thrust, driving all the side-pressure forming blades 6 to move synchronously and precisely towards the center of the mold. The blade tip of the side-pressure forming blade passes through the clearance groove 40 reserved on the inner punch 16 and stamps the sidewall of the second-stage molded product 32, integrally forming multiple ventilation louver holes 37.

[0076] Top punching: Since the main punch 17 and the outer punch 18 are rigidly fixed to the upper template 1, when the downward movement of the inner punch 16 stops due to the settling of the floating core mold 26, they continue to move downward relative to the inner punch 16 for the required punching distance. Their sharp ends penetrate the top of the housing, completing the punching of the central shaft hole and multiple end face air inlets 38. The punched-out scrap is discharged from the mold through the various levels of discharge channels below.

[0077] Edge removal: Also at the end of the stroke, the lower end face of the inner punch 16 upper ring platform 39 closes with the top of the lower die 22, just like scissors precisely removing excess, irregular flange waste from the outer edge of the workpiece.

[0078] Step 5: Reset and eject ( Figure 14 )

[0079] The punch press slide begins to rise, and the upper die plate 1 rises accordingly. Under the restoring force of each spring (11, 19, 21, 28), all moving parts automatically return to their initial positions. The annular drive wedge 8 rises, and the side-press forming blade 6 retracts outward under the action of its respective restoring spring. The floating core mold is pushed upward under the action of the powerful core mold support spring 28, and its upper surface acts as an ejector, smoothly ejecting the final formed product 33 from the cavity of the lower die 22, waiting for the robot to grasp it or for manual removal, thus completing a complete work cycle.

[0080] This invention integrates the traditionally fragmented and inefficient manufacturing process into a highly efficient and precise single-station solution through a sophisticated mechanical structure and timing coordination, providing strong technical support for the mass production of high-performance UAV motors.

[0081] Of course, the above description is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the embodiments of the present invention. The present invention is also not limited to the above examples, and all equivalent changes and improvements made by those skilled in the art within the scope of the present invention should fall within the patent coverage of the present invention.

Claims

1. An integrated stamping die for a brushless motor housing of a drone, comprising a lower die (4) fixed on a base (5) and an upper die (2) movable up and down relative to the lower die (4) along a guide post (3), characterized in that, The upper module (2) is a composite punch structure, including an outer punch (15) and an inner punch (16) coaxially arranged. The outer punch (15) and the inner punch (16) are elastically connected to the upper template (1) through elastic elements. The lower mold assembly (4) includes a fixed lower die (22) and a floating core mold (26) that can float up and down within the lower die (22). In one stamping stroke, the outer punch (15) and the inner punch (16) first descend together, cooperating with the lower die (22) to perform the first stage of drawing on the sheet metal (30); then, the outer punch (15) stops descending and acts as a pressure material on the flange edge of the workpiece, while the inner punch (16) continues to descend, pushing the floating core die (26) to sink, and performing the second stage of drawing on the workpiece; The end of the inner punch (16) is an inverted truncated cone, and the end face of the outer punch (15) is an annular conical surface with the same angle as the truncated cone. The top edge of the lower die (22) is a first-order conical surface (24), and the top surface of the floating core die (26) is a recessed second-order conical surface (25) with the same angle. In the initial state, the conical surfaces of the upper and lower dies are aligned to form matching upper and lower truncated cone contours for forming the top surface of the truncated cone of the motor housing. The upper module (2) also includes at least one punch fixed to the bottom surface of the upper template (1), the punch passing through the inner punch (16) for punching a hole in the top of the motor housing at the end of the stamping stroke; It also includes multiple radially movable side-press forming blades (6), and an annular drive wedge (8) fixed on the upper template (1) for driving the side-press forming blades (6) to move radially; after the second stage of deep drawing is completed, the annular drive wedge (8) drives the side-press forming blades (6) to move inward to stamp the side wall of the motor housing; The inner punch (16) is provided with a cutting edge; after the second stage of deep drawing is completed, the cutting edge of the inner punch (16) contacts and engages with the lower die (22) to remove the edge waste of the workpiece.

2. The integrated stamping die for the brushless motor housing of a drone according to claim 1, characterized in that, The punch includes a main punch (17) and multiple peripheral punches (18) arranged in a circular array; the floating core mold (26) is provided with a central blanking channel (29) corresponding to the main punch (17) and a core mold blanking channel (34) corresponding to the peripheral punches (18).

3. The integrated stamping die for the brushless motor housing of a drone according to claim 1, characterized in that, The inner punch (16) has a raised ring platform (39) on its side wall. The outer punch (15) is hung on the top surface of the ring platform (39) through the shoulder structure of its inner wall. The bottom surface of the ring platform (39) is a cutting edge.

4. The integrated stamping die for the brushless motor housing of a drone according to claim 1, characterized in that, The floating core mold (26) is elastically connected to the base (5) through the core mold support spring (28) at its bottom; the lower die (22) is provided with a core mold limiting pin (23) for limiting the floating position of the floating core mold (26).

5. The integrated stamping die for the brushless motor housing of a drone according to claim 1, characterized in that, The inner punch (16) has a clearance groove (40) on its outer peripheral wall to provide clearance space for the side-pressure forming knife (6) when it moves inward.

6. The integrated stamping die for the brushless motor housing of a drone according to claim 1, characterized in that, It also includes a pressure ring (12) elastically connected to the upper template (1) via a pressure ring spring (11), which is used to initially press the outer edge of the sheet (30) during the initial stage of stamping.

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