A quick-change short hollow rivet extrusion forming die

Abstract

The present invention discloses a quick-change short hollow rivet extrusion forming die and forming method, comprising an upper die assembly, a lower die assembly, a guide limit device and a discharge mechanism, wherein the upper die assembly comprises an upper die seat, a set screw and a quick-change punch, the quick-change punch is fixedly mounted on the upper die seat by the set screw, the lower die assembly comprises a lower die seat, a quick-change die and a set screw, the quick-change die is fixedly mounted on the lower die seat by the set screw, the guide limit device comprises a guide column and a limit sleeve, which are mounted on the lower die seat, and the discharge mechanism is mounted on the bottom of the lower die seat. By adopting a standard universal die seat, the punches and dies of different sizes can be quickly replaced, so that short hollow rivets of different sizes can be quickly and accurately extruded without excess, with low consumables, high quality and low cost, and the process is generally applicable to the production and processing of aircraft short hollow rivet parts.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft manufacturing, in particular to a short hollow rivet extrusion forming die for aircraft assembly. Background Art

[0002] Short hollow rivets are standard parts commonly used in aircraft assembly and are used in large quantities in aircraft assembly manufacturing. The shape of short hollow rivets is a hollow structure with equal wall thickness, which is a combination of a cylinder and an inverted cone. The external dimensions are relatively small and have different size specifications. Generally, the maximum outer diameter does not exceed 12mm, the height does not exceed 10mm, and the wall thickness is 0.8mm. The traditional processing method of short hollow rivets is to use a short tube of a certain specification to process it through a corresponding expansion forming process. Due to the small external dimensions of short hollow rivets, the size of the tube blank is also relatively small during the expansion process, which makes it inconvenient to clamp and the blank is easy to lose stability. The wall thickness of the tapered mouth of the processed parts is thinned a lot and is easy to crack. The processing quality is very unstable and the delivery qualification rate is low. Therefore, it is necessary to consider a processing method with simple structure, convenient operation and stable processing quality to solve the production status of unstable processing quality and low delivery qualification rate of short hollow rivets and ensure the development and production needs of aircraft. Summary of the invention

[0003] The purpose of the present application is to provide a quick-change short hollow rivet extrusion forming die, which can be suitable for the forming processing of short hollow rivet parts of various specifications.

[0004] In order to achieve the above objectives, the present invention adopts the following technical solutions to achieve the above objectives:

[0005] A quick-change short hollow rivet extrusion forming die includes an upper die assembly, a lower die assembly, a guide and limit device, and a discharge mechanism. The upper die assembly includes an upper die seat, a set screw, and a quick-change punch. The upper die seat is a disc-shaped structure. A cylindrical die handle connected to the worktable on a stamping machine is provided at the center of the upper surface. A stepped through hole is provided at the center. The lower end hole is a punch mounting hole. The hole diameter is a standard fixed size. Two guide post guide holes are provided on both sides of the die handle. Limit bosses are provided on the corresponding back sides. Side planes parallel to each other are provided on both sides, and threaded holes are formed on the side planes. The front end of the set screw is a columnar ball head shape. The quick-change punch is fixed to the punch mounting hole by the set screw. The lower die assembly includes a lower die seat, a quick-change die, and a set screw. The lower die seat has a stepped cylindrical structure. Side planes parallel to each other corresponding to the upper die seat are provided on both sides of the upper part, and threaded holes are formed on the side planes. The lower part is a chassis fixed to the lower workbench of the stamping machine, with a two-step through hole in the center. The large hole on the upper step is the die mounting hole with a standard fixed diameter, and the small hole on the lower step is the ejector rod hole. Two guide post fixing holes are arranged on both sides of the through hole, and the hole positions correspond to the guide holes of the guide posts of the upper die seat. A "semi-U"-shaped groove is arranged in the middle of the bottom surface, and an avoidance angle is arranged on the upper edge of the groove. Notch platforms are made on both sides of the chassis symmetrically with the groove, and concentric holes for the fulcrum are drilled; the quick-change die is fixed to the die mounting hole by a set screw; the guide limit device includes a guide post and a limit sleeve, the two guide posts are tightly fitted and fixed to the guide post fixing holes of the lower die seat, and the limit sleeve is sleeved on the guide post and placed on the upper surface of the lower die seat; the unloading mechanism is installed in the "semi-U"-shaped groove on the bottom surface of the lower die seat.

[0006] Furthermore, the quick-change punch is a stepped shaft structure, the lowermost end is a tapered guide section, the upward cylinder and the inverted cone combination section is a convex extrusion section, the surface roughness of the convex extrusion section is not higher than Ra0.2 and must be polished, and further upward is a reinforcement section. The uppermost end is a fixed section, and the outer diameter of the fixed section is a standard fixed size. A semi-concave circular upper anti-rotation groove is provided on the left side, and an upper tightening notch is provided on the right side. Two fixing screws pass through the flat surfaces on both sides of the upper die seat and are pressed tightly in the upper anti-rotation groove and the upper tightening notch of the quick-change punch in the punch mounting hole to fix it.

[0007] Furthermore, the quick-change die is a hollow cylindrical structure with an outer diameter of a standard fixed size, a center hole of a stepped through hole, the top hole of the blank positioning hole, a hole diameter equal to the outer diameter of the blank gasket, a bottom hole with a taper, and a middle part with a concave extrusion section. The internal shape of the hole maintains a short hollow rivet part wall thickness gap with the convex extrusion section of the quick-change punch. The surface roughness of the concave extrusion section is not higher than Ra0.2 and must be polished. A semi-concave circular lower anti-rotation groove is provided on the left side of the outer surface of the quick-change die, and a lower tightening notch is provided on the right side. Two fixing screws pass through the planes on both sides of the lower die seat and are pressed tightly in the lower anti-rotation groove and the lower tightening notch of the quick-change die in the die mounting hole to fix it.

[0008] Furthermore, the unloading mechanism includes a lever, a fulcrum shaft and a push rod. The lever consists of a resistance arm and a power arm with an angle of 150°. The resistance arm is a plate-like structure with an arc surface at the end, and the power arm is a cylindrical rod-like structure. A rotating hole is provided at the junction of the resistance arm and the power arm, and the rotating hole is slidably matched with the fulcrum shaft fixed in the concentric hole of the fulcrum of the lower die base; the push rod is a cylindrical structure with a flat top head and a spherical lower end head, which is installed in the center push rod hole of the lower die base, and the lower end head is attached to the arc surface of the lever resistance arm.

[0009] Furthermore, after the mold is assembled, the height dimension of the limit sleeve in the guide limit device is determined by the gap between the convex extrusion section and the concave extrusion section profile being equal to the material thickness of the short hollow rivet after the quick-change punch enters the quick-change concave mold cavity.

[0010] The method for extruding a short hollow rivet using the forming die comprises the following steps:

[0011] 1. The upper die assembly of the mold is fixedly mounted on the upper working table of the stamping machine through the die handle of the upper die seat, and the lower die assembly is fixedly mounted on the corresponding position of the lower working table of the stamping machine through the lower die plate chassis;

[0012] 2. Place the blank gasket in the blank positioning hole of the quick-change die (the blank gasket is processed by a special punching die, and the blank geometric dimensions are calculated based on the principle of "the material volume remains unchanged before and after the part is formed");

[0013] 3. The stamping machine drives the upper die assembly to move vertically downward under the precise guidance of the guide limit mechanism, the quick-change punch enters the central hole of the quick-change die, and the tapered lead-in section enters the inner hole of the blank gasket;

[0014] 4 The quick-change punch continues to move downward, and the convex extrusion section drives the raw material into the concave extrusion section of the quick-change die to extrude and form the short hollow rivet;

[0015] 5 When the limiting boss of the upper die seat contacts the upper end surface of the limiting sleeve on the lower die seat, the upper die assembly stops moving downward, and the thicker blank gasket is extruded into a thin-walled short hollow rivet;

[0016] 6. The stamping machine is unloaded, the upper die assembly moves upward and returns to its original position, and the quick-change punch is released from the quick-change die as the upper die assembly moves upward;

[0017] 7. The power arm of the lever in the unloading mechanism is forced downward, and the end of the resistance arm hits the ejector rod upward to eject the short hollow rivet from the mold, and a short hollow rivet is then processed;

[0018] 8 Repeat the second and subsequent steps in sequence to complete the batch production of short hollow rivets.

[0019] This application utilizes the basic principle of cold extrusion forming of metal materials, and ensures the extrusion forming quality of short hollow rivets by adopting the working surfaces of the punch and die with high finish index requirements; uses the guide limit device to effectively control the thickness change of the blank material during the extrusion forming process, and completes the precise extrusion forming of the corresponding specifications of the flat thick material into a three-dimensional hollow structure thin-walled short hollow rivet part; uses the lever-type unloading mechanism with simple structure and convenient operation to complete the smooth demoulding of the short hollow rivet parts after forming; with the help of stamping machine equipment, the mold structure can realize the rapid and precise extrusion forming of short hollow rivet parts without excess, low consumables, high quality and low cost. By adopting a standard universal die base, the punch and die of different size series can be quickly replaced, and the production and processing of short hollow rivets of various specifications can be realized, which has universal applicability to the production and processing of thin-walled hollow parts such as short hollow rivets for aircraft assembly.

[0020] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Blank gasket structure diagram;

[0022] Figure 2 Short hollow rivets;

[0023] Figure 3 A structural diagram of a quick-change short hollow rivet extrusion forming die;

[0024] Figure 4 Internal structure diagram of upper mold assembly;

[0025] Figure 5 Internal structure diagram of the lower mold assembly;

[0026] Figure 6 Internal structure diagram of upper mold;

[0027] Figure 7 The internal structure diagram of the lower mold;

[0028] Figure 8 Quick-change punch structure diagram;

[0029] Fig. 9 Internal structure diagram of quick-change die;

[0030] Fig.10 Structural diagram of the unloading mechanism.

[0031] Explanation of the numbers in the figure: 1. Blank gasket; 2. Short hollow rivet; 3. Upper die assembly; 4. Lower die assembly; 5. Guide limit device; 6. Unloading mechanism; 7. Upper die seat; 8. Set screw; 9. Quick-change punch; 10. Quick-change die; 11. Lower die seat; 12. Guide post; 13. Limiting ring; 14. Guide post guide hole; 15. Die handle; 16. Punch mounting hole; 17. Limiting boss; 18. Fulcrum concentric hole; 19. Concave Die mounting hole; 20, guide column fixing hole; 21, "half U" groove; 22, upper tightening notch; 23, introduction section; 24, convex extrusion section; 25, reinforcement section; 26, upper anti-rotation groove; 27, fixing section; 28, lower tightening notch; 29, blank positioning hole; 30, lower anti-rotation groove; 31, concave extrusion section; 32, lever 32; 33, ejector rod; 34, resistance arm; 35, fulcrum shaft; 36, rotation hole; 37, power arm DETAILED DESCRIPTION

[0032] Figure 1-2 It is the structural diagram of the blank washer 1 and the structural diagram of the short hollow rivet 2.

[0033] Figures 3 to 10 A quick-change short hollow rivet extrusion forming die comprises an upper die assembly 3, a lower die assembly 4, a guide limit device 5 and a discharge mechanism 6. The upper die assembly 3 includes an upper die base 7, a fixing screw 8 and a quick-change punch 9. The upper die base 7 is a disc-shaped structure. A cylindrical die handle 15 connected to the workbench on the stamping machine is provided in the center of the upper surface. A stepped through hole is provided in the center, and the lower end hole is a punch mounting hole 16 with a standard fixed hole diameter. Two guide column guide holes 14 are provided on both sides of the die handle 15, and limiting bosses 17 are provided on the corresponding back sides. Side planes parallel to each other are provided on both sides, and threaded holes are formed on the side planes; the front end of the fixing screw 8 is a columnar ball head shape; the quick-change punch 9 is fixedly installed with the punch mounting hole 16 by the fixing screw 8; the lower die assembly 4 includes a lower die base 11, a quick-change die 10 and a fixing screw 8. The outer shape of the lower die base 11 is a stepped cylindrical structure. Side planes parallel to each other corresponding to the upper die base 7 are provided on both sides of the upper part, and threaded holes are formed on the side planes. The lower part is The chassis under the punching machine is fixed with a two-step through hole in the center. The upper large hole is the die mounting hole 19 with a standard fixed size, and the lower small hole is the ejector hole. Two guide post fixing holes 20 are arranged on both sides of the through hole, and the hole positions correspond to the guide post guide holes 14 of the upper die seat 7. A "semi-U"-shaped groove 21 is arranged in the middle of the bottom surface, and an avoidance angle is arranged on the upper edge of the groove. Cutting platforms are made on both sides of the chassis symmetrically with the groove, and fulcrum concentric holes 18 are drilled; the quick-change die 10 is fixed to the die mounting hole 19 by a set screw 8; the guide limit device 5 includes a guide post 12 and a limit sleeve 13, the two guide posts 12 are tightly fitted and fixed with the guide post fixing holes 20 of the lower die seat 11, and the limit sleeve 13 is sleeved on the guide post 12 and placed on the upper surface of the lower die seat 11; the unloading mechanism 6 is installed in the "semi-U"-shaped groove 21 on the bottom surface of the lower die seat 11.

[0034] The quick-change punch 9 is a stepped shaft structure, with a tapered introduction section 23 at the bottom, a convex extrusion section 24 formed by the combination of the cylinder and the inverted cone, and a reinforcement section 25 upward. The top is a fixed section 27, and the outer diameter of the fixed section 27 is a standard fixed size. A semi-concave upper anti-rotation groove 26 is provided on the left side, and an upper tightening notch 22 is provided on the right side. Two set screws 8 pass through the flat surfaces on both sides of the upper die seat 7 and are pressed tightly in the upper anti-rotation groove 26 and the upper tightening notch 22 of the quick-change punch 8 in the punch mounting hole 16 to fix it.

[0035] The quick-change die 10 is a hollow cylindrical structure with an outer diameter of a standard fixed size. The center hole is a stepped through hole. The uppermost hole is a blank positioning hole 29 with a hole diameter equal to the outer diameter of the blank gasket 1. The lowermost hole is provided with a taper. The middle part is a concave extrusion section 31. The internal shape of the hole maintains a short hollow rivet part 2 wall thickness gap with the convex extrusion section 24 of the quick-change punch 9. The surface roughness of the concave extrusion section 31 is not higher than Ra0.2 and must be polished. A semi-concave circular lower anti-rotation groove 30 is provided on the left side of the outer surface of the quick-change die 10, and a lower tightening notch 28 is provided on the right side. Two fixing screws 8 pass through the two side planes of the lower die seat 11 and are pressed tightly in the lower anti-rotation groove 30 and the lower tightening notch 28 of the quick-change die 10 in the die mounting hole 19 to fix it.

[0036] The unloading mechanism 6 includes a lever 32, a fulcrum shaft 35 and a push rod 33. The lever 32 is composed of a resistance arm 34 and a power arm 37 with an angle of 150°. The resistance arm 34 is a plate-like structure with an arc surface at the end, and the power arm 37 is a cylindrical rod-like structure. A rotating hole 36 is provided at the junction of the resistance arm 34 and the power arm 37. The rotating hole 36 is slidably matched with the fulcrum shaft 35 fixed in the concentric hole 18 of the fulcrum of the lower mold base 11; the push rod 33 is a cylindrical structure with a flat top head and a spherical lower end head. It is installed in the center push rod hole of the lower mold base 11, and the lower end head is attached to the arc surface of the lever resistance arm 34.

[0037] After the mold is assembled, the height dimension of the limiting sleeve 13 in the guide limiting device 5 is determined by the gap between the convex extrusion section 24 and the concave extrusion section 31 being equal to the material thickness of the short hollow rivet 2 after the quick-change punch 9 enters the cavity of the quick-change die 10.

[0038] The method for extruding a short hollow rivet using the forming die comprises the following steps:

[0039] 1 The upper die assembly 3 of the mold is fixedly mounted on the upper working table of the stamping machine through the die handle 15 of the upper die base 7, and the lower die assembly 4 is fixedly mounted on the corresponding position of the lower working table of the stamping machine through the chassis of the lower die base 11;

[0040] 2. Place the blank gasket 1 in the blank positioning hole 29 of the quick-change die 10 (the blank gasket is processed by a special punching die, and the geometric dimensions of the blank are calculated based on the principle of "the material volume remains unchanged before and after the part is formed");

[0041] 3 The stamping machine drives the upper die assembly 3 to move vertically downward under the precise guidance of the guide limit device 5, the quick-change punch 9 enters the central hole of the quick-change die 10, and the tapered lead-in section 23 enters the inner hole of the blank gasket 1;

[0042] The quick-change punch 9 continues to move downward, and the convex extrusion section 24 drives the raw material into the concave extrusion section 31 of the quick-change concave die 10 to extrude and form the short hollow rivet 2;

[0043] When the limiting boss 17 of the upper die seat 5 contacts the upper end surface of the limiting sleeve 13 on the lower die seat 11, the upper die assembly 3 stops moving downward, and the thicker blank gasket 1 is extruded into a thin-walled short hollow rivet 2;

[0044] 6 The stamping machine is unloaded, the upper die assembly 3 moves upward and returns to its original position, and the quick-change punch 9 is released from the quick-change die 10 as the upper die assembly 3 moves upward;

[0045] 7 applies downward force to the power arm 37 of the lever 32 in the unloading mechanism 6, and the end of the resistance arm 34 strikes the ejector rod 33 upward, ejecting the short hollow rivet 2 from the mold, and a short hollow rivet 2 is then processed;

[0046] 8 Repeat the second and subsequent steps in sequence to complete the batch production of short hollow rivets 2.

Claims

1. A quick-change short hollow rivet extrusion forming die, characterized in that It includes an upper die assembly, a lower die assembly, a guide limit device and a discharge mechanism. The upper die assembly includes an upper die seat, a set screw and a quick-change punch. The upper die seat is a disc-shaped structure. The center of the upper surface is provided with a cylindrical die handle connected to the workbench of the stamping machine. A stepped through hole is provided in the center, and the lower end hole is a punch mounting hole. The hole diameter is a standard fixed size. Two guide post guide holes are provided on both sides of the die handle, and limit bosses are provided on the corresponding back sides. Side planes parallel to each other are provided on both sides, and threaded holes are made on the side planes; the set screws are provided with threaded holes on the side planes. The front end is a cylindrical ball head shape; the quick-change punch is fixedly installed with the punch mounting hole by a set screw; the lower die assembly includes a lower die seat, a quick-change die and a set screw. The lower die seat is a stepped cylindrical structure. The upper two sides are provided with side planes parallel to each other corresponding to the upper die seat. The side planes are provided with threaded holes. The lower part is a chassis fixed to the lower workbench of the stamping machine. There are two-step through holes in the center. The upper large hole is the die mounting hole, and the hole diameter is a standard fixed size. The lower small hole is the ejector hole. Two guide holes are provided on both sides of the through hole. The column fixing hole corresponds to the guide hole of the guide column of the upper die seat. A "semi-U"-shaped groove is set in the middle of the bottom surface, and an avoidance angle is set on the upper edge of the groove. The cutting platform is made on both sides of the chassis symmetrically with the groove and the fulcrum concentric holes are drilled; the quick-change die is fixed to the die mounting hole by a set screw; the guide limit device includes a guide column and a limit sleeve, the two guide columns are tightly fixed with the guide column fixing hole of the lower die seat, and the limit sleeve is sleeved on the guide column and placed on the upper surface of the lower die seat; the unloading mechanism is installed in the "semi-U" groove on the bottom surface of the lower die seat In the invention, the unloading mechanism comprises a lever, a fulcrum shaft and a push rod. The lever consists of a resistance arm and a power arm with an included angle of 150°. The resistance arm is a plate-like structure with an arc surface at the end. The power arm is a cylindrical rod-like structure. A rotating hole is provided at the junction of the resistance arm and the power arm. The rotating hole is slidably matched with the fulcrum shaft fixed in the concentric hole of the fulcrum of the lower die base. The push rod is a cylindrical structure with a flat top head and a spherical lower end head, which is installed in the center push rod hole of the lower die base, and the lower end head is attached to the arc surface of the lever resistance arm.

2. A quick-change short hollow rivet extrusion forming die according to claim 1, characterized in that The quick-change punch is a stepped shaft structure, with the lowest end being a tapered guide section, the upward cylindrical and inverted cone combining section being a convex extrusion section, the surface roughness of the convex extrusion section not exceeding Ra0.2 and requiring polishing, the further upward section being a reinforcement section, the highest end being a fixed section, the outer diameter of the fixed section being a standard fixed size, a semi-concave circular upper anti-rotation groove being provided on the left side, and an upper tightening notch being provided on the right side.

3. The quick-change short hollow rivet extrusion forming die according to claim 1, characterized in that The quick-change die is a hollow cylindrical structure with an outer diameter of a standard fixed size. The center hole is a stepped through hole. The uppermost hole is a blank positioning hole with a hole diameter equal to the outer diameter of the blank gasket. The lowermost hole is provided with a taper. The middle part is a concave extrusion section. The internal shape of the hole maintains a short hollow rivet part wall thickness gap with the convex extrusion section of the quick-change punch. The surface roughness of the concave extrusion section is not higher than Ra0.2 and must be polished. A semi-concave circular lower anti-rotation groove is provided on the left side of the outer surface of the quick-change die, and a lower tightening cut is provided on the right side.

4. The quick-change short hollow rivet extrusion forming die according to claim 1, characterized in that After the mold is assembled, the height of the limit sleeve in the guide limit device is determined by the gap between the convex extrusion section and the concave extrusion section profile being equal to the wall thickness of the short hollow rivet after the quick-change convex die enters the quick-change concave die cavity.

5. A quick-change short hollow rivet extrusion forming method, characterized in that The method of using the quick-change short hollow rivet extrusion forming die according to claim 1 to perform extrusion forming comprises the following steps: 5-1 The upper die assembly of the mold is fixedly mounted on the upper working table of the stamping machine through the die handle of the upper die seat, and the lower die assembly is fixedly mounted on the corresponding position of the lower working table of the stamping machine through the lower die plate chassis; 5-2 Place the blank gasket in the blank positioning hole of the quick-change die; 5-3 The stamping machine drives the upper die assembly to move vertically downward under the precise guidance of the guide limit mechanism, the quick-change punch enters the central hole of the quick-change die, and the tapered lead-in section enters the inner hole of the blank gasket; 5-4 The quick-change punch continues to move downward, and the convex extrusion section drives the raw material into the concave extrusion section of the quick-change concave die to extrude and form the short hollow rivet parts; 5-5 When the limiting boss of the upper die seat contacts the upper end surface of the limiting sleeve on the lower die seat, the upper die assembly stops moving downward, and the thicker blank gasket is extruded into a thin-walled short hollow rivet; 5-6 The stamping machine is unloaded, the upper die assembly moves upward and returns to its original position, and the quick-change punch is released from the quick-change die as the upper die assembly moves upward; 5-7 The power arm of the lever in the unloading mechanism is forced downward, and the end of the resistance arm hits the ejector rod upward to eject the short hollow rivet from the mold, and a short hollow rivet part is then processed; 5-8 Repeat the subsequent steps from 5-2 to 5-7 in sequence to complete the batch production of short hollow rivet parts.

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