CN117345752B - Lightweight self-locking nut for aerospace, cold extrusion die and forming method - Google Patents
Lightweight self-locking nut for aerospace, cold extrusion die and forming method Download PDFInfo
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- CN117345752B CN117345752B CN202311403191.1A CN202311403191A CN117345752B CN 117345752 B CN117345752 B CN 117345752B CN 202311403191 A CN202311403191 A CN 202311403191A CN 117345752 B CN117345752 B CN 117345752B
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- 238000000641 cold extrusion Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000000463 material Substances 0.000 claims abstract description 115
- 230000007246 mechanism Effects 0.000 claims abstract description 39
- 230000009471 action Effects 0.000 claims description 13
- 238000000465 moulding Methods 0.000 claims description 13
- 239000013585 weight reducing agent Substances 0.000 abstract description 22
- 208000016261 weight loss Diseases 0.000 abstract description 21
- 239000002184 metal Substances 0.000 abstract description 8
- 238000012545 processing Methods 0.000 abstract description 6
- 239000011159 matrix material Substances 0.000 abstract description 4
- 239000000835 fiber Substances 0.000 abstract description 2
- 230000009286 beneficial effect Effects 0.000 description 14
- 230000008569 process Effects 0.000 description 12
- 230000000694 effects Effects 0.000 description 9
- 238000001125 extrusion Methods 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 238000005728 strengthening Methods 0.000 description 6
- 238000013461 design Methods 0.000 description 4
- 230000006872 improvement Effects 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 239000007769 metal material Substances 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 238000007493 shaping process Methods 0.000 description 3
- 238000005482 strain hardening Methods 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 235000014121 butter Nutrition 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000000280 densification Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000007514 turning Methods 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J13/00—Details of machines for forging, pressing, or hammering
- B21J13/02—Dies or mountings therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
- B21J5/02—Die forging; Trimming by making use of special dies ; Punching during forging
- B21J5/025—Closed die forging
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/64—Making machine elements nuts
- B21K1/70—Making machine elements nuts of special shape, e.g. self-locking nuts, wing nuts
- B21K1/707—Self-locking nuts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B39/00—Locking of screws, bolts or nuts
- F16B39/22—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening
- F16B39/28—Locking of screws, bolts or nuts in which the locking takes place during screwing down or tightening by special members on, or shape of, the nut or bolt
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Forging (AREA)
Abstract
The invention discloses a lightweight self-locking nut for aerospace, a cold extrusion die and a forming method, and belongs to the technical field of nut processing. The self-locking nut comprises a nut body, the nut body comprises a wrenching section and a flange section, a plurality of weight-reduction inclined plane structures and flange conical surface structures are arranged on the flange section, the flange conical surface structures are arranged between the weight-reduction inclined plane structures, and weight-reduction nest structures are arranged on the weight-reduction inclined plane structures. The cold extrusion die comprises an upper die mechanism, a lower die mechanism and a linkage mechanism, wherein the lower die mechanism comprises a female die, a cavity is formed in the female die, a cylindrical cavity section, a flange cavity section, a screwing-on bearing cavity section and a screwing-on cavity section are sequentially formed in the cavity from top to bottom, the flange cavity section is provided with an inclined surface structure and a conical surface structure, and a convex ball is arranged on the inclined surface structure. The self-locking nut is subjected to cold extrusion, so that metal fibers of the self-locking nut continuously and smoothly flow and the cold deformation and hardening characteristics of materials are realized, the matrix structure is compact, the strength is greatly improved, and the self-locking nut has the characteristics of weight reduction and high bearing capacity.
Description
Technical Field
The invention relates to a lightweight self-locking nut for aerospace, a cold extrusion die and a forming method, and belongs to the technical field of fastener manufacturing.
Background
The self-locking nut is one of the most widely-required fasteners in the aerospace field, and the single machine of a certain fighter plane can be used for hundreds of thousands of fasteners. The model weight reduction in the aerospace field has important significance for improving the thrust-weight ratio and reducing the launching and flight costs. The self-locking nut realizes that the weight reduction contributes greatly to the whole weight reduction of the model, but the current nut weight reduction design is less, so the self-locking nut with the weight reduction is required.
In addition, the weight reduction can be realized by carrying out the lightweight design of 'material reduction' on the self-locking nut structure, but the 'material reduction' inevitably leads to the reduction of bearing capacity due to the weak structure, and the 'material reduction' and the 'bearing capacity improvement' of the structure have a constraint relation.
The 'material reduction' light self-locking nut has a complex structure, and the existing forming technology of the product is 'machining' or 'hot heading'. "machining" is a process of removing material, which has low material utilization, slow machining efficiency, and cut metal streamlines, further resulting in reduced load carrying capacity. The hot upsetting is a pressure forming processing mode after heating the blank, the cross section area of the blank is changed from small to large in the deformation process, the blank is limited by material flow, and the product structure is difficult to form at one time and is not full; the heating control of the blank is improper, so that the microstructure is easy to overheat and burn, and the product batch is scrapped; the hot working cannot retain the deformation strengthening effect, and the strength improvement cannot be realized.
The defects of the prior art are limited, the design and lifting space of the self-locking nut structure is extremely limited, and the molding method cannot meet the engineering application requirements of the aviation and aerospace model light-weight high-bearing self-locking nut.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a lightweight self-locking nut for aerospace, a cold extrusion die and a forming method.
The technical scheme for solving the technical problems is as follows: the utility model provides an aerospace is with lightweight self-locking nut, includes the nut body, this internal screw that is equipped with of nut, the nut body is including turning section and flange section, turn the surface of turning the section and be equipped with turn the structure of twisting, be equipped with a plurality of weight-reduction inclined plane structures and a plurality of flange conical surface structures on the surface of flange section, the flange conical surface structure sets up adjacent between the weight-reduction inclined plane structure, every be equipped with on the weight-reduction inclined plane structure and subtract heavy nest structure.
The beneficial effects of the invention are as follows: the structure of the weight-reducing inclined plane is arranged on the flange section, the weight-reducing nest structure is further arranged on the weight-reducing inclined plane, the weight-reducing purpose of the self-locking nut is achieved, meanwhile, the use requirement of the self-locking nut can be met, and the self-locking nut applied to the aerospace field has important significance in improving the thrust-weight ratio and reducing the emission and flight cost.
On the basis of the technical scheme, the invention can be improved as follows.
Further, the number and positions of the weight-reducing inclined surface structures correspond to the number and positions of edges of the screwing structure.
Further, the wrenching structure is a hexagonal structure, the weight-reducing inclined plane structure is provided with six weight-reducing inclined plane structures, and the six weight-reducing inclined plane structures are respectively in one-to-one correspondence with six sides of the hexagonal structure.
The adoption of the further scheme has the beneficial effects that a proper wrenching structure can be selected according to actual needs, a hexagonal structure can be adopted, and the positions and the number of the weight-reducing inclined surface structures and the positions and the number of the edges of the wrenching structure are correspondingly arranged.
The invention also relates to a lightweight self-locking nut cold extrusion die for aerospace, which comprises an upper die mechanism, a lower die mechanism and a linkage mechanism, wherein the upper die mechanism comprises an upper die plate, an upper die sleeve arranged on the upper die plate and a punch head arranged on the upper die sleeve through a positioning mechanism;
The lower die mechanism comprises a lower die plate, a lower die seat arranged on the lower die plate and a female die arranged on the lower die seat, a cavity is arranged in the female die, a cylindrical cavity section, a flange cavity section, a screwing-on bearing cavity section and a screwing-on cavity section are sequentially arranged in the cavity from top to bottom, a plurality of inclined surface structures and conical surface structures are arranged on the inner wall of the flange cavity section, the conical surface structures are arranged between the adjacent inclined surface structures, convex balls for forming weight-reducing nest structures of self-locking nuts are arranged on the inclined surface structures, the size of the screwing-on bearing cavity section is smaller than that of the screwing-on cavity section, and the shapes of the screwing-on bearing cavity section and the screwing-on bearing cavity section are matched with those of the screwing-on structure;
The linkage mechanism comprises a push rod, a material returning plate and a pair of pull rods, wherein the upper part of the push rod stretches into the cavity, the shape of the upper part of the push rod is matched with that of the wrenching bearing cavity section, a push rod limiting part is arranged at the lower part of the push rod, a push rod limiting shoulder matched with the push rod limiting part is arranged on a lower die plate or a lower die base, the material returning rod is arranged below the push rod, the material returning plate is arranged below the material returning rod, the material returning plate is connected with the lower part of the pull rod, the upper part of the pull rod penetrates through the lower die plate and the upper die plate, and a pull rod limiting part is arranged at the upper end of the pull rod limiting plate, and a pull rod limiting shoulder matched with the pull rod limiting part is arranged on the upper die plate.
The self-locking nut forming device has the advantages that the blank can be placed in the cylindrical cavity section, the press machine moves downwards to drive the upper die plate and the punch to move downwards, the punch is inserted into the female die cavity and is forced downwards to extrude downwards from the die cavity under the action of pressure after being contacted with the blank, the forming height and the forming size of the self-locking nut are accurately controlled by adjusting the length of the ejector rod, and finally the self-locking nut forming is completed; the return stroke of the upward movement of the press is utilized to drive the pull rod to move upward, the upward pushing force is transmitted to the formed part through the linkage of the material returning plate, the material returning rod and the ejector rod, and finally the part is pushed out to finish material returning. The size of the wrenching bearing cavity section is smaller than that of the wrenching cavity section, so that when the material flows through the bearing, the product wrenching structure size is guaranteed to be high in precision and consistency; meanwhile, the material flowing through the bearing is not contacted with the wrenching cavity section, so that the forming contact area of the material can be reduced, and the forming resistance is reduced. In the cold extrusion molding process of the die cavity, the blank is subjected to the vertical downward pressure action of the punch under the closed space, the cross-sectional area is reduced from large to small, the material forcedly flows through each structural part of the die cavity, the material is completely filled, the molding precision is high, and the structural fullness is good; in the deformation process, the metal microscope always keeps a continuous and smooth state, meanwhile, the material deformation is in a three-way compressive stress state of the punch, the ejector rod and the inner wall of the cavity, so that the material structure is precise, and meanwhile, the cold work hardening characteristic of the metal material cold deformation is utilized, so that the product strength is greatly improved. In the process that the material flows through the female die convex ball structure to form the weight reducing nest, the material is subjected to the reverse extrusion strengthening effect of the convex ball, metal grain streamline is gathered along the radial direction of the convex ball structure, obvious dislocation strengthening effect is formed at the weak structure position, and the bearing deformation resistance of the self-locking nut is further improved. In a word, the cold extrusion die is adopted, so that the self-locking nut has high bearing capacity while having high weight reduction.
Further, the ejector rod comprises an upper ejector rod and a lower ejector rod, the shape of the upper ejector rod is matched with the shape of the wrenching bearing cavity section, the length of the upper ejector rod is equal to or greater than that of the cavity, and the ejector rod limiting piece is arranged at the bottom of the lower ejector rod.
The upper ejector rod is matched with the punch to perform cold extrusion on the blank during cold extrusion, after forming, the upper ejector rod moves upwards under the action of the material returning plate and the material returning rod to eject the formed blank, and the ejector rod is matched with the two rods in a contact manner, so that the requirements of the upper ejector rod for entering the cavity for cold extrusion and pushing can be met, and meanwhile, the upper movement limit position and the lower movement limit position of the ejector rod can be restrained through the ejector rod limiting piece of the lower ejector rod.
Further, a material returning limiting piece is arranged on the material returning rod, a material returning limiting shoulder matched with the material returning limiting piece is arranged on the lower die plate or the lower die base, and the outer diameter of the material returning limiting piece is smaller than that of the ejector rod limiting piece.
The technical scheme has the beneficial effects that the material returning limiting piece can limit the maximum downward displacement of the material returning rod, and the material returning rod is prevented from falling out of the lower die plate when the material returning plate moves downwards.
Further, the positioning mechanism comprises a positioning notch and a positioning rod, the positioning notch is arranged on the punch, the positioning rod is in threaded connection with the upper die sleeve, and the rod end of the positioning rod acts on the positioning notch.
The adoption of the further scheme has the beneficial effects that the punch is restrained on the upper die sleeve through the positioning rod, so that the stable positioning of the punch is realized.
Further, a guide mechanism is further arranged between the upper die plate and the lower die plate, the guide mechanism comprises at least one pair of guide posts, the guide posts are arranged on the lower die plate, and the upper ends of the guide posts are connected with the upper die plate through guide sleeves.
The adoption of the further scheme has the beneficial effects that the movement of the upper template is guided and limited, so that the movement stability and accuracy of the upper template are ensured.
Further, the pull rod comprises an upper pull rod and a lower pull rod, and the upper pull rod is connected with the lower pull rod through a pull rod nut.
The beneficial effects of adopting above-mentioned further scheme are that, the pull rod adopts split structure, including last pull rod and lower pull rod, simple to operate is convenient for adjust the length of pull rod through the pull rod nut moreover to when the pull rod can move on the drift, the flitch of returning can accurately act on the material returning pole, and the material returning pole acts on the ejector pin and releases the female die ejection of compact with the blank after the shaping.
Further, a material returning sleeve is further arranged in the lower die holder, a first lower die pad is arranged between the material returning sleeve and the female die, a second lower die pad is arranged between the material returning sleeve and the lower die plate, rod holes are formed in the first lower die pad, the material returning sleeve and the second lower die pad, and the hole diameter of the rod hole of the material returning sleeve is larger than that of the rod hole of the first lower die pad and that of the rod hole of the second lower die pad.
The technical scheme has the beneficial effects that the ejector rod and the material returning rod are installed through the material returning sleeve and the lower die pad, the limit shoulder is formed through the difference of the apertures, and subsequent maintenance is facilitated.
Further, the convex ball is fixedly arranged in the female die.
The beneficial effect of adopting above-mentioned further scheme is that, protruding ball can be fixed in the die cavity of female die directly, fixedly establish on the die cavity internal inclined plane structure, can directly act on the shaping that reduces heavy nest structure on the blank realization blank.
Further, the convex ball is movably arranged in the female die, and a ball positioning groove for positioning the convex ball is arranged on the inner wall of the female die.
The beneficial effect of adopting above-mentioned further scheme is that, the protruding ball can also keep in the die cavity of female die through the ball constant head tank, and the rolling friction is little to the wearing and tearing of protruding ball between protruding ball and the blank in the in-process of cold extrusion blank.
Further, a die shank connected with the press is arranged on the upper die plate.
The cold extrusion die has the beneficial effects that the cold extrusion die is convenient to be connected with the press through the die shank.
The invention also relates to a cold extrusion molding method of the lightweight self-locking nut for aerospace, which adopts the cold extrusion die of the lightweight self-locking nut for aerospace, and comprises the following molding steps:
1) Preparing a blank, wherein the blank is cylindrical, and the outer diameter of the cylindrical blank is consistent with the outer diameter of the self-locking nut flange section;
2) Placing the blank into a cavity of a female die;
3) The press machine acts to drive the upper die mechanism to move downwards, the punch stretches into the cavity of the female die to contact with the blank, the blank moves downwards in the female die to enter the cavity of the female die under the action of pressure, and the blank is formed by cold extrusion under the action of the punch and the ejector rod;
4) The press returns to drive the pull rod to move upwards, and upward pushing force is transmitted to the forming part through the linkage of the material returning plate, the material returning rod and the ejector rod, so that the forming part is pushed out to complete material returning;
5) Waiting for the next blank.
The beneficial effects of the invention are as follows: the light self-locking nut is processed by a cold extrusion die in a cold extrusion deformation mode, the sectional area of a blank in a closed space in the forming process is reduced from large to small, the self-locking nut is fully formed at one time with high precision, and the strength of a matrix is greatly improved by utilizing the cold work hardening characteristic of cold deformation of a metal material; the cold extrusion deformed metal crystal grain is in a three-dimensional compressive stress state, so that the whole structure of the material is compact, the structure around the material is more compact by utilizing the dislocation strengthening effect of the back extrusion of the weight-reducing nest structure, and the bearing deformation resistance of the key stress part at the junction of the wrenching structure and the flange section conical surface is improved. According to the forming method, adverse effects of structural weight reduction design on bearing capacity are made up through material microstructure densification and cold deformation reinforcement, the purpose of self-locking nut matrix grain streamline densification and strength improvement is achieved, adverse effects of structural material reduction on bearing capacity can be made up, and finally the self-locking nut has the characteristics of weight reduction and high bearing capacity.
Further, a single-side gap between the blank and the cavity is 0.02mm.
The further scheme has the beneficial effects that the blank can be prevented from being flash in the cold extrusion process of the punch, and the forming quality of the nut is ensured while the requirement that the blank enters the cavity is met.
Further, the length of the wrenching bearing cavity section is less than or equal to 1.5mm.
The further scheme has the beneficial effects of reducing the contact area between the blank and the cavity and reducing the forming resistance.
Drawings
FIG. 1 is a schematic view of the structure of a self-locking nut of the present invention;
FIG. 2 is a schematic diagram of the front view of the self-locking nut of the present invention;
FIG. 3 is a schematic top view of the self-locking nut of the present invention;
FIG. 4 is a schematic left-hand view of the self-locking nut of the present invention;
FIG. 5 is a schematic view of a cold extrusion die for a self-locking nut according to the present invention;
FIG. 6 is a schematic top view of the female mold of the present invention;
FIG. 7 is a schematic cross-sectional view of FIG. 6 along the direction A-A;
FIG. 8 is a schematic view of the structure of the blank of the present invention in a female mold in a formed state;
FIG. 9 is a schematic view of the structure of the punch of the present invention;
FIG. 10 is a schematic view of another embodiment of the female mold of the present invention;
FIG. 11 is a schematic view of the cross-sectional structure along the direction B-B in FIG. 10;
In the figure, 1, a self-locking nut; 101. a wrenching structure; 102. a weight-reducing inclined plane structure; 103. a weight-reducing nest structure; 104. a flange conical surface structure; 2. an upper template; 3. an upper die sleeve; 4. a punch; 401. positioning the notch; 5. a positioning rod; 6. a lower template; 7. a lower die holder; 8. a female die; 801. a cylindrical cavity section; 802. a flange cavity section; 8021. an inclined plane structure; 8022. a convex ball; 8023. a conical surface structure; 803. pulling and twisting the bearing cavity section; 804. pulling the cavity section; 9. an upper ejector rod; 10. a lower ejector rod; 100. ejector rod limiting piece; 11. a material returning rod; 110. a material returning limiting piece; 12. a material returning plate; 13. a pull rod; 130. a pull rod limiting piece; 14. a pull-down rod; 15. a pull rod nut; 16. a material returning sleeve; 17. a first lower die pad; 18. a second lower die pad; 19. a guide post; 20. guide sleeve; 21. a fixing plate; 22. an upper die pad; 23. a die handle; 24. and (5) blank material.
Detailed Description
The principles and features of the present invention are described below in connection with examples, which are set forth only to illustrate the present invention and not to limit the scope of the invention.
As shown in fig. 1-4, a lightweight self-locking nut 1 for aerospace comprises a nut body, screw holes are formed in the nut body, the nut body comprises a screwing section and a flange section, the outer surface of the screwing section is provided with a screwing structure 101, the outer surface of the flange section is provided with a plurality of weight-reducing inclined surface structures 102 and a plurality of flange conical surface structures 104, the flange conical surface structures 104 are arranged between the adjacent weight-reducing inclined surface structures 102, and each weight-reducing inclined surface structure 102 is provided with a weight-reducing nest structure 103.
The number and positions of the weight-reducing inclined structures 102 correspond to the number and positions of the sides of the screwing structure 101.
The wrenching structure 101 is a hexagonal structure, the number of the weight-reducing inclined surface structures 102 is six, and the six weight-reducing inclined surface structures 102 are respectively in one-to-one correspondence with the six sides of the hexagonal structure. The appropriate screwing structure 101 can be selected according to actual needs, and of course, a hexagonal structure can be adopted, and the positions and the number of the weight-reducing inclined surface structures 102 and the positions and the number of the edges of the screwing structure 101 are correspondingly arranged.
As shown in fig. 5-9, the invention also relates to a cold extrusion die for the lightweight self-locking nut 1 for aerospace, which comprises an upper die mechanism, a lower die mechanism and a linkage mechanism, wherein the upper die mechanism comprises an upper die plate 2, an upper die sleeve 3 arranged on the upper die plate 2 and a punch 4 arranged on the upper die sleeve 3 through a positioning mechanism;
The lower die mechanism comprises a lower die plate 6, a lower die seat 7 arranged on the lower die plate 6, and a female die 8 arranged on the lower die seat 7, wherein a cavity is arranged in the female die 8, a cylindrical cavity section 801, a flange cavity section 802, a screwing bearing cavity section 803 and a screwing cavity section 804 are sequentially arranged in the cavity from top to bottom, a plurality of inclined surface structures 8021 and conical surface structures 8023 are arranged on the inner wall of the flange cavity section 802, the conical surface structures 8023 are arranged between the adjacent inclined surface structures 8021, convex balls 8022 are arranged on the inclined surface structures 8021, the size of the screwing bearing cavity section 803 is smaller than that of the screwing cavity section 804, and the shapes of the screwing bearing cavity section 803 and the screwing cavity section 804 are matched with the shape of the screwing structure 101;
the size of the wrenching bearing cavity section 803 is smaller than that of the wrenching cavity section 804, so that when the material flows through the bearing, the product wrenching structure size is guaranteed to be high in precision and consistency; meanwhile, the material flowing through the bearing is not contacted with the wrenching cavity section, so that the forming contact area of the material can be reduced, and the forming resistance is reduced.
The linkage mechanism comprises a push rod, a material returning rod 11, a material returning plate 12 and a pair of pull rods, wherein the upper part of the push rod stretches into the cavity, the shape of the upper part of the push rod is matched with that of the wrenching bearing cavity 803, a push rod limiting piece 100 is arranged at the lower part of the push rod, a push rod limiting shoulder matched with the push rod limiting piece 100 is arranged on the lower die plate 6 or the lower die holder 7, the material returning rod 11 is arranged below the push rod, the material returning plate 12 is arranged below the material returning rod 11, the material returning plate 12 is connected with the lower part of the pull rods, the upper part of the pull rods penetrates through the lower die plate 6 and the upper die plate 2, a pull rod limiting piece 130 is arranged at the upper end of the pull rods, and a pull rod limiting shoulder matched with the pull rod limiting piece 130 is arranged on the upper die plate 2; when the punch 4 descends, the ejector rod and the punch 4 are matched to extrude the blank 24, and when the punch 4 ascends, the ejector rod moves upwards under the action of the material returning plate 12 and the material returning rod 11 to push the extruded blank 24 out of the female die 8 for discharging.
The ejector rod comprises an upper ejector rod 9 and a lower ejector rod 10, the shape of the upper ejector rod 9 is matched with the shape of the twisting bearing cavity section 803, the length of the upper ejector rod 9 is equal to or greater than that of the cavity, and the ejector rod limiting piece 100 is arranged at the bottom of the lower ejector rod 10. The upper ejector rod 9 is matched with the punch 4 to perform cold extrusion on the blank 24 during cold extrusion, after forming, the upper ejector rod 9 moves upwards under the action of the material returning plate 12 and the material returning rod 11 to eject the formed blank 24, and the ejector rod adopts two rods to be in contact and matched, so that the requirements that the upper ejector rod 9 can enter a cavity for cold extrusion and pushing can be met, and meanwhile, the upper moving limit position and the lower moving limit position of the ejector rod can be restrained through the ejector rod limiting piece 100 of the lower ejector rod 10.
The material returning rod 11 is provided with a material returning limiting part 110, the lower die plate 6 or the lower die seat 7 is provided with a material returning limiting shoulder matched with the material returning limiting part 110, and the outer diameter of the material returning limiting part 110 is smaller than that of the ejector rod limiting part 100. The material returning limiting member 110 can limit the maximum downward displacement of the material returning rod 11, so as to prevent the material returning rod 11 from being separated from the lower die plate 6 when the material returning plate 12 moves downward.
The positioning mechanism comprises a positioning notch 401 and a positioning rod 5, wherein the positioning notch 401 is arranged on the punch 4, the positioning rod 5 is in threaded connection with the upper die sleeve 3, and the rod end of the positioning rod 5 acts on the positioning notch 401. The punch 4 is restrained on the upper die sleeve 3 through the positioning rod 5, so that the punch 4 is stably positioned.
A guide mechanism is further arranged between the upper die plate 2 and the lower die plate 6, the guide mechanism comprises at least one pair of guide posts 19, the guide posts 19 are arranged on the lower die plate 6, and the upper ends of the guide posts 19 are connected with the upper die plate 2 through guide sleeves 20. The movement of the upper template 2 is guided and limited, so that the movement stability and accuracy of the upper template 2 are ensured.
The pull rod comprises an upper pull rod 13 and a lower pull rod 14, and the upper pull rod 13 is connected with the lower pull rod 14 through a pull rod nut 15. The pull rod adopts split structure, including last pull rod 13 and lower pull rod 14, simple to operate is convenient for adjust the length of pull rod through pull rod nut 15 moreover to when the pull rod can be moved up in drift 4, the material returning plate 12 can accurately be acted on material returning rod 11, and material returning rod 11 acts on the ejector pin and releases die 8 ejection of compact with the blank 24 after the shaping.
The lower die holder 7 is internally provided with a material returning sleeve 16, a first lower die pad 17 is arranged between the material returning sleeve 16 and the female die 8, a second lower die pad 18 is arranged between the material returning sleeve 16 and the lower die plate 6, rod holes are formed in the first lower die pad 17, the material returning sleeve 16 and the second lower die pad 18, and the hole diameter of the rod hole of the material returning sleeve 16 is larger than that of the rod hole of the first lower die pad 17 and that of the rod hole of the second lower die pad 18. The ejector rod and the material returning rod 11 are installed through the material returning sleeve 16 and the lower die pad, and the limit shoulder is formed through the difference of the apertures, so that the subsequent maintenance is convenient.
The convex ball 8022 is fixedly arranged in the female die 8. The convex ball 8022 can be directly fixed in the cavity of the female die 8, is fixedly arranged on an inclined surface structure in the cavity, and can directly act on the blank 24 to realize the forming of the weight-reducing nest structure 103 on the blank 24.
The upper part of the female die 8 is provided with a positioning ring table, and the female die 8 is connected with the lower die holder 7 through a fixing plate 21 and a fixing bolt. Realizing the installation and positioning of the female die 8 on the lower die holder 7.
The upper die sleeve 3 is arranged on the upper die plate 2 through fastening bolts.
An upper die pad 22 is further arranged in the upper die sleeve 3, and the upper die pad 22 is arranged between the punch 4 and the upper die plate 2. The position of the punch 4 can be adjusted through the thickness of the upper die pad 22, the adjustment is more convenient, the wear and maintenance of the upper die pad 22 are convenient, and the cost is low.
The upper die plate 2 is provided with a die shank 23 connected with a press machine. The connection of the cold extrusion die to the press is facilitated by means of the die shank 23.
In embodiment 2, as shown in fig. 10 and 11, a mold core is disposed in the female mold 8, the mold cavity is disposed in the mold core, and the mold core is made of an alloy material. The alloy mold core adopted has better toughness and strength, and the cold extrusion forming precision of the self-locking nut 1 is higher.
In embodiment 3, the convex ball 8022 is movably disposed in the female die 8, and a ball positioning groove for positioning the convex ball 8022 is disposed on the inner wall of the female die 8. The stud 8022 may also be held in the cavity of the female die 8 by a ball detent, reducing rolling friction between the stud 8022 and the billet 24 during cold extrusion of the billet 24. Or the movable convex ball is more convenient for the processing and forming of the self-locking nut under the same extrusion.
The invention also relates to a cold extrusion molding method of the lightweight self-locking nut for aerospace, which adopts the cold extrusion die of the lightweight self-locking nut for aerospace, and comprises the following molding steps:
1) Preparing a blank 24, wherein the blank 24 is cylindrical, and the outer diameter of the cylindrical blank 24 is consistent with the outer diameter of the flange section of the self-locking nut 1;
2) Placing the blank 24 into the cavity of the female mould 8;
3) The press machine acts to drive the upper die mechanism to move downwards, the punch 4 stretches into the cavity of the female die 8 to contact with the blank 24, the blank 24 moves downwards in the female die 8 to enter the cavity of the female die 8 under the action of pressure, and the blank 24 is formed by cold extrusion under the action of the punch 4 and the ejector rod;
4) The press returns to drive the pull rod to move upwards, and upward pushing force is transmitted to the forming part through the linkage of the material returning plate 12, the material returning rod 11 and the ejector rod, so that the forming part is pushed out to finish material returning;
5) Waiting for the next blank 24.
The single-sided gap between the blank 24 and the cavity is 0.02mm. The requirement of the blank 24 entering the cavity is met, the generation of flash of the blank 24 in the cold extrusion process of the punch 4 can be avoided, and the forming quality of the nut is ensured.
The length of the wrenching bearing cavity section 803 is less than or equal to 1.5mm. The contact area of the blank and the die cavity is reduced, and the forming resistance is reduced.
After a batch of workpieces is processed in the forming step, the abrasion condition of the convex balls 8022 is checked, and if the abrasion condition of the convex balls 8022 exceeds the requirement, a group of convex balls 8022 is replaced. The stud 8022 may be adhered to the ball detent using butter. The butter can be smeared to facilitate the positioning of the convex ball 8022, and is also beneficial to reducing the rolling friction force during extrusion.
The detailed structure of the cavity of the female die 8 is shown in fig. 7, and comprises a cylindrical cavity section 801, a flange cavity section 802, a conical surface structure 8023 arranged on the flange cavity section 802, an inclined surface structure 8021, a convex ball 8022, a screwing bearing cavity section 803 and a screwing cavity section 804. The cylindrical cavity section 801 realizes the outer diameter structural dimension molding of the flange section of the self-locking nut 1; the conical surface structure 8023, the inclined surface structure 8021 and the convex ball 8022 realize the forming of the self-locking nut 1 flange conical surface structure 104, the weight-reducing inclined surface structure 102 and the weight-reducing nest structure 103; the self-locking nut 1 is wrenched and the locking structure is formed by wrenching the bearing cavity section and the wrenching cavity section, the length of the bearing is not more than 1.5mm, the contact area of the blank 24 and the cavity is reduced, and the forming resistance is reduced. In the cold extrusion molding process of the cavity, the blank 24 is positioned in the closed space, the cross-sectional area is reduced from large to small under the action of the vertical downward pressure of the punch 4, the material forcedly flows through each structural part of the cavity, the material is completely filled, the molding precision is high, and the structural fullness is good; in the cold extrusion deformation process, the metal microscope always keeps a continuous and smooth state, meanwhile, the material deformation is in a three-way compressive stress state, so that the material structure is precise, and meanwhile, the cold work hardening characteristic of the metal material cold deformation is utilized, so that the product strength is greatly improved. In the process that the material flows through the convex sphere 8022 of the female die 8 to form the weight-reducing nest structure, the material is subjected to the back extrusion strengthening effect of the convex sphere 8022, metal grain flow lines are radially gathered along the convex sphere 8022, a remarkable dislocation strengthening effect is formed at the weak structure position, and the bearing deformation resistance of the product is further improved. The self-locking nut is subjected to cold extrusion, so that metal fibers of the self-locking nut continuously and smoothly flow and the cold deformation and hardening characteristics of materials are realized, the matrix structure is compact, the strength is greatly improved, and the self-locking nut has the characteristics of weight reduction and high bearing capacity.
In the process of processing and forming, a female die or a die core can be replaced after a batch of self-locking nuts are processed. For movable convex balls, the convex balls can be replaced in groups more frequently, so that the consistency of the processing quality of the ball socket structure of the self-locking nut is ensured.
The die is suitable for a press, ensures concentric accurate positioning of an upper die mechanism and a lower die mechanism through a guide post 19, and completes cold extrusion forming processing of the self-locking nut 1 by utilizing one complete stroke of a punch press: as shown in the left view of fig. 8, a cylindrical blank 24 is placed in a cavity of a female die 8, the outer diameter of the blank 24 is selected according to the outer diameter size of a flange of the self-locking nut 1, and a gap of 0.02mm is kept between the blank and a single side of the cavity of the female die 8; the downward movement stroke of the press drives the upper die plate 2 and the punch 4 to move downwards, the punch 4 is inserted into the cavity of the female die 8 and is contacted with the blank 24, the blank 24 is forced downwards to move downwards for extrusion under the action of pressure, the accurate control of the forming height and size is realized by adjusting the length of the ejector rod, and finally the cold extrusion forming of the self-locking nut 1 shown in the right diagram of fig. 8 is completed. Finally, the return stroke of the upward movement of the punch is utilized to drive the pull rod mechanism to move upwards, the upward push-out force is transmitted to the formed part through the upper ejector rod by means of the linkage of the material returning plate 12, the material returning rod 11 and the lower ejector rod 10, and finally the part is pushed out, so that material returning is completed. The self-locking nut formed by cold extrusion through the forming die realizes a remarkable weight reduction effect, and takes English to manufacture a 0.25-28UNJF-3B thread specification product as an example, compared with the traditional hexagonal flange self-locking nut, the weight reduction ratio of the self-locking nut is 15%; compared with the lightest nut weight reduction ratio of the same class in the industry at present, the weight reduction ratio is 5 percent. Moreover, the cold extrusion die is adopted, so that the self-locking nut has high load-bearing capacity while the weight is reduced.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (7)
1. The utility model provides a lightweight self-locking nut cold extrusion molding method for aerospace, adopts lightweight self-locking nut cold extrusion mould for aerospace, lightweight self-locking nut cold extrusion mould for aerospace includes mould mechanism, lower mould mechanism and link gear, lightweight self-locking nut for aerospace includes the nut body, be equipped with the screw in the nut body, the nut body includes wrenches section and flange section, the surface of wrenching section is equipped with wrenches structure (101), be equipped with a plurality of weight-reducing inclined plane structures (102) and a plurality of flange conical surface structures (104) on the surface of flange section, flange conical surface structures (104) set up between adjacent weight-reducing inclined plane structures (102), be equipped with on every weight-reducing inclined plane structure (102) and subtract heavy nest structure (103); the upper die mechanism is characterized by comprising an upper die plate (2), an upper die sleeve (3) arranged on the upper die plate (2) and a punch (4) arranged on the upper die sleeve (3) through a positioning mechanism;
The lower die mechanism comprises a lower die plate (6), a lower die seat (7) arranged on the lower die plate (6) and a female die (8) arranged on the lower die seat (7), a cavity is arranged in the female die (8), a cylindrical cavity section (801), a flange cavity section (802), a screwing bearing cavity section (803) and a screwing cavity section (804) are sequentially arranged in the cavity from top to bottom, a plurality of inclined surface structures (8021) and conical surface structures (8023) are arranged on the inner wall of the flange cavity section (802), the conical surface structures (8023) are arranged between the adjacent inclined surface structures (8021), a convex ball (8022) is arranged on the inclined surface structures (8021), the size of the screwing bearing cavity section (803) is smaller than that of the screwing cavity section (804), and the shapes of the screwing bearing cavity section (803) and the screwing bearing cavity section (804) are matched with the shape of the screwing structure (101);
The convex ball (8022) is movably arranged in the female die (8), and a ball positioning groove for positioning the convex ball (8022) is formed in the inner wall of the female die (8);
The linkage mechanism comprises a push rod, a material returning rod (11), a material returning plate (12) and a pair of pull rods, wherein the upper part of the push rod stretches into the cavity, the shape of the upper part of the push rod is matched with that of the wrenching bearing cavity section (803), a push rod limiting part (100) is arranged at the lower part of the push rod, a push rod limiting shoulder is arranged on the lower die plate (6) or the lower die holder (7), the material returning rod (11) is arranged below the push rod, the material returning plate (12) is arranged below the material returning rod (11), the material returning plate (12) is connected with the lower part of the pull rod, the upper part of the pull rod penetrates through the lower die plate (6) and the upper die plate (2), the upper end of the pull rod limiting part (130) is arranged at the upper end of the pull rod, and the pull rod limiting shoulder is arranged on the upper die plate (2).
The molding steps are as follows:
1) Preparing a blank (24), wherein the blank (24) is cylindrical, and the outer diameter of the cylindrical blank (24) is consistent with the outer diameter of the flange section of the self-locking nut (1);
2) Placing a blank (24) into a cavity;
3) The press machine acts to drive the upper die mechanism to move downwards, the punch (4) stretches into the cavity to contact with the blank (24), the blank (24) moves downwards in the female die (8) under the action of pressure, and the blank (24) is formed by cold extrusion under the action of the punch (4) and the ejector rod;
4) The press returns to drive the pull rod to move upwards, and upward pushing force is transmitted to the forming part through the linkage of the material returning plate (12), the material returning rod (11) and the ejector rod, so that the forming part is pushed out to complete material returning;
5) Waiting for the next blank (24).
2. The cold extrusion forming method of the lightweight self-locking nut for aerospace according to claim 1, wherein the ejector rod comprises an upper ejector rod (9) and a lower ejector rod (10), the shape of the upper ejector rod (9) is matched with the shape of the wrenching bearing cavity section (803), the length of the upper ejector rod (9) is equal to or greater than the length of the cavity, and the ejector rod limiting piece (100) is arranged at the bottom of the lower ejector rod (10);
and/or the material returning rod (11) is provided with a material returning limiting piece (110), the lower die plate (6) or the lower die holder (7) is provided with a material returning limiting shoulder, and the outer diameter of the material returning limiting piece (110) is smaller than the outer diameter of the ejector rod limiting piece (100).
3. The cold extrusion forming method of the lightweight self-locking nut for aerospace according to claim 1, wherein the positioning mechanism comprises a positioning notch (401) and a positioning rod (5), the positioning notch (401) is arranged on the punch (4), the positioning rod (5) is in threaded connection with the upper die sleeve (3), and a rod end of the positioning rod (5) acts on the positioning notch (401).
4. The cold extrusion forming method of the lightweight self-locking nut for aerospace according to claim 1, wherein a guide mechanism is further arranged between the upper die plate (2) and the lower die plate (6), the guide mechanism comprises at least one pair of guide posts (19), the guide posts (19) are arranged on the lower die plate (6), and the upper ends of the guide posts (19) are connected with the upper die plate (2) through guide sleeves (20).
5. The cold extrusion forming method of the lightweight self-locking nut for aerospace according to claim 1, wherein the number and the positions of the weight-reducing inclined surface structures (102) correspond to the number and the positions of edges of the screwing structure (101).
6. The cold extrusion forming method of the lightweight self-locking nut for aerospace according to claim 1, wherein the wrenching structure (101) is a hexagonal structure, six weight-reducing inclined surface structures (102) are arranged, and the six weight-reducing inclined surface structures (102) are respectively in one-to-one correspondence with six sides of the hexagonal structure.
7. The aerospace lightweight self-locking nut cold extrusion molding method as claimed in claim 1, wherein a single-sided gap between the blank (24) and the cavity is 0.02mm, and/or the length of the wrenching bearing cavity section (803) is 1.5mm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311403191.1A CN117345752B (en) | 2023-10-26 | 2023-10-26 | Lightweight self-locking nut for aerospace, cold extrusion die and forming method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311403191.1A CN117345752B (en) | 2023-10-26 | 2023-10-26 | Lightweight self-locking nut for aerospace, cold extrusion die and forming method |
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| CN117345752A CN117345752A (en) | 2024-01-05 |
| CN117345752B true CN117345752B (en) | 2024-05-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202311403191.1A Active CN117345752B (en) | 2023-10-26 | 2023-10-26 | Lightweight self-locking nut for aerospace, cold extrusion die and forming method |
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| CN103350122A (en) * | 2013-06-28 | 2013-10-16 | 洛阳北川重工机械有限公司 | Gear shaft cold extruding process and mould |
| CN206972725U (en) * | 2017-02-22 | 2018-02-06 | 西安智同航空科技有限公司 | A kind of adjustable Closely locking nut of light-duty setting angle |
| CN109396208A (en) * | 2018-12-03 | 2019-03-01 | 中北大学 | A kind of steel different wall thickness " H " shape connector synchronization extrusion forming method |
| CN217440502U (en) * | 2022-05-19 | 2022-09-16 | 浙江瑞利紧固件有限公司 | Improved p-type self-locking nut |
| CN217713287U (en) * | 2022-06-24 | 2022-11-01 | 成都迈特航空制造有限公司 | Hexagonal flange self-locking nut for aviation |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060160629A1 (en) * | 2005-01-14 | 2006-07-20 | Fu-Kuang Hsu | Method for extrusion molding of a self-locked nut |
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2023
- 2023-10-26 CN CN202311403191.1A patent/CN117345752B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB462150A (en) * | 1935-04-30 | 1937-03-03 | Elastic Stop Nut Corp | Improvements in or relating to the manufacture of self-locking nuts |
| CN101837384A (en) * | 2010-04-01 | 2010-09-22 | 陆颂荫 | Cold extrusion die of hexagonal locknut with pad |
| CN103350122A (en) * | 2013-06-28 | 2013-10-16 | 洛阳北川重工机械有限公司 | Gear shaft cold extruding process and mould |
| CN206972725U (en) * | 2017-02-22 | 2018-02-06 | 西安智同航空科技有限公司 | A kind of adjustable Closely locking nut of light-duty setting angle |
| CN109396208A (en) * | 2018-12-03 | 2019-03-01 | 中北大学 | A kind of steel different wall thickness " H " shape connector synchronization extrusion forming method |
| CN217440502U (en) * | 2022-05-19 | 2022-09-16 | 浙江瑞利紧固件有限公司 | Improved p-type self-locking nut |
| CN217713287U (en) * | 2022-06-24 | 2022-11-01 | 成都迈特航空制造有限公司 | Hexagonal flange self-locking nut for aviation |
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| CN117345752A (en) | 2024-01-05 |
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