CN114378237B - Forging steel piston skirt forming method and forming die thereof - Google Patents
Forging steel piston skirt forming method and forming die thereof Download PDFInfo
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- CN114378237B CN114378237B CN202210036458.7A CN202210036458A CN114378237B CN 114378237 B CN114378237 B CN 114378237B CN 202210036458 A CN202210036458 A CN 202210036458A CN 114378237 B CN114378237 B CN 114378237B
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- 238000005242 forging Methods 0.000 title claims abstract description 94
- 238000000034 method Methods 0.000 title claims abstract description 52
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 40
- 239000010959 steel Substances 0.000 title claims abstract description 40
- 230000008569 process Effects 0.000 claims abstract description 30
- 238000003825 pressing Methods 0.000 claims abstract description 3
- 238000004088 simulation Methods 0.000 claims description 9
- 238000005457 optimization Methods 0.000 claims description 5
- 238000005516 engineering process Methods 0.000 claims description 2
- 238000001125 extrusion Methods 0.000 abstract description 9
- 230000000903 blocking effect Effects 0.000 abstract description 8
- 238000004080 punching Methods 0.000 abstract description 2
- 230000035882 stress Effects 0.000 description 52
- 238000004519 manufacturing process Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 238000002485 combustion reaction Methods 0.000 description 3
- 230000032683 aging Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 208000037656 Respiratory Sounds Diseases 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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- 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
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- 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
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- 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
- B21J13/08—Accessories for handling work or tools
- B21J13/14—Ejecting devices
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- 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
- B21K1/18—Making machine elements pistons or plungers
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Abstract
The invention discloses a forged steel piston skirt forming method and a forming die thereof, comprising the following steps: 1) Placing the prepared blank on a lower mold core in a lower mold sleeve; 2) The upper die core is contacted with the blank first, the upper die stress ring is closed with the lower die sleeve, and the upper die core, the upper die stress ring, the lower die sleeve and the lower die core form a closed cavity; 3) Continuously pressing down the upper mold core, reversely extruding the blank to form and filling the closed cavity to obtain a formed workpiece; 4) The upper mold core and the upper mold stress ring are moved upwards to separate from the forming workpiece; 5) The lower die core is moved upwards, and the formed workpiece is ejected out of the lower die sleeve; the forging processing of the blank can be completed by utilizing the repeated deformation process of first punching forging deformation and then extrusion deformation in the one-time forging forming process, so that the blocking forging forming processing of the forged steel piston skirt is realized, and the forming precision is ensured.
Description
Technical Field
The invention relates to the technical field of metal plastic precision forming, in particular to a forged steel piston skirt forming method and a forming die thereof.
Background
With the continuous improvement of energy saving and emission reduction requirements, the strengthening index and emission standard of the engine are continuously improved, wherein the piston is a core component affecting the performance of the engine. Aluminum alloy pistons for diesel and gas engines have been progressively replaced by wrought steel pistons.
Forged steel pistons have now been developed in split construction, with the following production processes: forging and forming the piston head and the skirt blank respectively, rough machining the piston head and the skirt blank, welding the piston head and the skirt, detecting welding seam quality by ultrasonic waves, finishing the piston, and treating the surface of the piston, wherein the forming difficulty of the piston skirt blank in the shape of a thin wall deep cylinder is the greatest.
For example, chinese patent publication No. CN 213496269U discloses a steel piston forging die, which comprises two sets of relatively independent dies, namely a pre-forging die and a final-forging die, wherein the pre-forging die comprises an upper pre-forging die and a lower pre-forging die, the final-forging die comprises an upper final-forging die and a lower final-forging die, the inner cavities of the upper pre-forging die and the lower pre-forging die comprise a skirt part, a core part and a combustion chamber, an upper die plugging groove and a lower die plugging groove which are communicated with each other are arranged between the upper pre-forging die and the lower pre-forging die, a flash groove is also arranged between the upper die and the lower die of the pre-forging die, the flash groove is communicated with the combustion chamber in a matched manner by the upper die plugging groove and the lower die plugging groove which are communicated with each other in the pre-forging die, and the flash groove is communicated with the combustion chamber in the final-forging die. According to the scheme, through the design of the flash groove, materials can overflow in the forging process and can overflow into the flash groove, and therefore, the scheme adopts an open forging scheme, the open forging scheme cannot be stably formed, flash is reserved, and the product precision is low.
For another example, chinese patent with the publication number CN 201720380U discloses a piston forging die, which comprises an upper die portion and a lower die portion, an upper pad is placed under the upper die base, a fixing plate is in interference fit with a male die, the shape and size of an inner cavity of a formed piston during forging of the male die, meanwhile, the fixing plate is in interference fit with a guide sleeve, the guide sleeve is positioned, a female die is in interference fit with a guide post, the guide post is in clearance fit with the guide sleeve during die closing, the correct positions of the upper die and the lower die are ensured when the die is closed, the outer shape and size of the formed piston during forging of a cavity in the middle of the female die, a pushing piece is placed at the bottom of the cavity of the female die, a lower pad is placed under the female die, and a lower die base is placed under the lower pad. It can also be seen in the drawings of this document that a groove is also provided between the die and the fixing plate, which groove can be used as an overflow or flash groove, so that this solution is likewise an open forging solution.
In summary, the forming of the forging steel piston skirt blank at present generally adopts an open forging method on a forging press, and the forging is performed in three steps of upsetting, pre-forging and final forging. The general forging method for forging the forged steel piston skirt blank has the advantages that the design and manufacturing difficulty of the die is low, the production process is simple, the constraint force on metal materials in the forming process is small, stable forming cannot be realized, the near net forming of the forged steel piston skirt blank with the thin-wall deep cylinder shape is difficult to realize, the material utilization rate is low, the method has a plurality of steps and flash generation, and workpieces cannot be clamped stably in the automatic production process.
Disclosure of Invention
The invention aims to provide a forging steel piston skirt forming method and a forming die thereof, which solve the problems in the prior art, and by arranging an upper die core and an upper die stress ring which move relatively, in the forging forming process, the upper die core is firstly contacted with a blank to perform impact forging deformation, then a closed cavity is formed, and the upper die core is continuously pressed in the closed cavity, so that the blank is reversely extruded to be filled in the closed cavity, thereby completing the forging processing of the blank by utilizing the multiple deformation processes of first impact forging deformation and then extrusion deformation in the one-time forging forming process, realizing the blocking forging forming processing of the forging steel piston skirt, and ensuring the forming precision.
In order to achieve the above object, the present invention provides the following solutions:
the invention provides a forged steel piston skirt forming method, which comprises the following steps of:
(1) Placing the prepared blank on a lower mold core in a lower mold sleeve;
(2) The upper die core is contacted with the blank firstly, the upper die stress ring is closed with the lower die sleeve, the upper die core, the upper die stress ring, the lower die sleeve and the lower die core form a closed cavity, and the blank is positioned in the closed cavity;
(3) Continuously pressing down the upper mold core, reversely extruding the blank to form and filling the closed cavity to obtain a formed workpiece;
(4) The upper mold core and the upper mold stress ring are moved upwards to separate from the forming workpiece;
(5) And (3) moving the lower die core upwards, and ejecting the formed workpiece from the lower die sleeve.
Preferably, the die structure and die cavity optimization results are determined using computer numerical modeling techniques.
Preferably, the aspect ratio of the billet prepared in step (1) is not less than 1.3 and not more than 2.5.
Preferably, in the step (1), the blank is placed on the lower mold core by clamping with a manipulator or a hand clamp, and the blank placement position is limited by the inner diameter of the lower mold sleeve or a circular groove of the middle cavity of the lower mold core, so that the positioning and placement of the blank are completed.
The invention also provides a forged steel piston skirt forming die, which comprises an upper die assembly and a lower die assembly, wherein the upper die assembly comprises an upper die stress ring and an upper die core arranged in the upper die stress ring in a sliding manner, the lower die assembly comprises a lower die sleeve and a lower die core arranged in the lower die sleeve in a sliding manner, the upper die core, the lower die core, the upper die stress ring and the lower die sleeve can enclose a closed cavity for forging forming, the upper die core is used for bearing the pressure of an inner sliding block of a press, and the upper die stress ring is used for bearing the pressure of an outer sliding block of the press.
Preferably, the inner diameter side of the upper die stress ring is provided with a draft angle, a step or an arc is arranged, and the inner diameter side of the lower die sleeve is not provided with the draft angle.
Preferably, a flange is arranged at the top of the upper die core, and a return spring is abutted between the bottom surface of the flange and the top surface of the upper die stress ring.
Preferably, a limit stop is arranged on the outer side of the upper mold core, a through hole penetrating through the inner slide block is formed in the top of the limit stop, and the bottom of the limit stop is connected to the upper mold stress ring.
Preferably, the outer diameter side of the upper die stress ring is sleeved on the inner diameter side of the upper die sleeve, and the outer diameter side of the upper die stress ring and the inner diameter side of the upper die sleeve are provided with matched taper.
Preferably, the upper die core corresponds to the opening direction of the formed forged steel piston skirt.
Compared with the prior art, the invention has the following technical effects:
(1) According to the invention, by arranging the upper mold core and the upper mold stress ring which move relatively, in the forging forming process, the upper mold core is firstly contacted with the blank to perform impact forging deformation, then a closed cavity is formed, and the upper mold core is continuously pressed in the closed cavity, so that the blank is reversely extruded to be filled in the closed cavity, thereby completing the forging processing of the blank by utilizing the multiple deformation processes of firstly punching forging deformation and then extrusion deformation in the one-time forging forming process, realizing the blocking forging forming processing of the forged steel piston skirt, and ensuring the forming precision;
(2) In the invention, in the primary forging precision forming process, the forging forming is firstly carried out in a preliminary blocking way, then in a closed space, the upper mold core carries out secondary extrusion forming on the blank to finish the forming process of the piston skirt, the existing forging steps of pre-forging and final forging are reduced into one step, the pre-forging and final forging of the forged steel piston skirt are finished on one set of mold at one station, the service life of the mold is not influenced, the cost of the mold is greatly reduced, and the production efficiency can be improved on the basis;
(3) The invention is provided with the draft angle on the inner diameter side of the upper die stress ring and is provided with the steps or the circular arcs, and the draft angle is not arranged on the inner diameter side of the lower die sleeve, so that the formed workpiece can be prevented from moving along with the upper die core in the die drawing process, the formed workpiece is smoothly separated from the upper die core and the upper die stress ring, and then the formed workpiece is ejected out of the lower die sleeve through the upper and lower die cores, thereby finally realizing smooth demolding of the formed workpiece, facilitating stripping of the formed workpiece, avoiding die clamping, ensuring stable forming and facilitating automatic production;
(4) The flange is arranged at the top of the upper die core, the reset spring is abutted between the bottom surface of the flange and the top surface of the upper die stress ring, and the upper die core can smoothly move upwards when the inner slide moves upwards through the arrangement of the reset spring, so that the upper die core can be ensured to be smoothly separated from a formed workpiece;
(5) The outer diameter side of the upper die stress ring and the inner diameter side of the upper die sleeve are provided with matched taper, the outer diameter side of the upper die stress ring is sleeved on the inner diameter side of the upper die sleeve through the taper, so that the upper die stress ring is in interference fit connection with the conical surface of the upper die sleeve, and when the upper die stress ring has irreparable defects such as abrasion, crack, aging and the like, the upper die stress ring can be conveniently replaced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a cross-sectional view of the present invention;
FIG. 2 is a cross-sectional view A-A of FIG. 1;
FIG. 3 is a schematic view of the upper module structure;
FIG. 4 is a schematic view of the enlarged partial structure of B in FIG. 3;
FIG. 5 is a schematic view of the structure of a formed workpiece (forged steel piston skirt);
FIG. 6 is another directional view of FIG. 5;
FIG. 7 is a schematic illustration of the application of the present invention to a double-acting hot die forging press;
FIG. 8 is a schematic illustration of the application of the present invention to a double-acting hydraulic machine;
1, an inner sliding block; 2. an outer slider; 3. a limit stop; 4. an upper die sleeve; 5. a return spring; 6. an upper mold core; 7. an upper die stress ring; 8. a lower mold core; 9. a lower die sleeve; 10. a lower main ejector rod; 100. forming a workpiece; 200. a forming die; 300. double-acting hot die forging press; 400. double-acting hydraulic press.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a forging steel piston skirt forming method and a forming die thereof, which are used for solving the problems in the prior art, and by arranging an upper die core and an upper die stress ring which move relatively, in the forging forming process, the upper die core is firstly contacted with a blank to perform impact forging deformation, then a closed cavity is formed, and the upper die core is continuously pressed in the closed cavity, so that the blank is reversely extruded to be filled in the closed cavity, thereby completing the forging processing of the blank by utilizing the multiple deformation processes of first impact forging deformation and then extrusion deformation in the one-time forging forming process, realizing the blocking forging forming processing of the forging steel piston skirt, and ensuring the forming precision.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
As shown in fig. 1 to 8, the invention provides a forged steel piston skirt forming method, which comprises the following steps:
(1) The prepared blank is placed on a lower die core 8 in a lower die sleeve 9, the lower die core 8 can slide in the lower die sleeve 9, the bottom of the lower die core 8 can be fixed at a designated position through a lower main ejector rod 10, the position is kept unchanged in the forging process, and after the forging is completed, the lower die core 8 is moved upwards by lifting the lower main ejector rod 10 so as to eject a formed workpiece 100. The blank is a bar stock, and chamfering is needed to reduce the influence of the corners of the bar stock on forming stress. In preparation, the blank can be heated to be above the recrystallization temperature through induction to improve the thermoplasticity and reduce the deformation resistance, and the blank of different materials is heated at different temperatures, wherein the materials adopted by the prior general steel piston skirt are 42CrMo4, 38MnVS6 and the like, and the heating temperature is generally between Ac3 and 300-400 ℃. The temperature of the blank cannot be too high or too low, and the material is easy to burn due to the too high temperature of the blank, so that the material is scrapped; the material temperature is too low, so that higher deformation resistance is easy to form, the plasticity is poor, and the phenomenon of insufficient filling of the forged steel piston skirt is easy to occur. In addition, after the blank is heated, the surface of the blank inevitably has oxide scales, and the oxide scales are removed and then the formal forging process is carried out.
(2) The upper die core 6 and the upper die stress ring 7 can be simultaneously pressed by the inner slide 1 and the outer slide 2 of the equipment, and the used equipment can be a double-acting hydraulic press 400 or a double-acting hot die forging press 300. The blank has certain height, and in the process of going down on upper mold core 6 and upper mold stress ring 7, upper mold core 6 contacts with the blank first, takes place the impact forging with the blank first for the blank forges the deformation, and the diameter grow to contact upper mold stress ring 7 gradually, along with this process goes on, upper mold stress ring 7 and lower die cover 9 closure, and at this moment, upper mold core 6, upper mold stress ring 7 and lower die cover 9, lower mold core 8 form closed die cavity, and the blank is located closed die cavity. After the closed cavity is formed, the upper mold core 6 may still move downward, and thus the size of the formed closed cavity is gradually changed along with the movement of the upper mold core 6.
(3) The upper mold core 6 continues to move downwards under the pushing of the inner slide block 1 to extrude the blank in the closed cavity, at the moment, the upper mold core 6 moves downwards, and the forming direction of the blank is opposite to that of the blank, so that the reverse extrusion forming is formed, and the thin skirt edge of the forged steel piston skirt can be ensured to be filled fully. And when the inner slide block 1 reaches the set sliding stroke, stopping, finally, filling the blank into the closed cavity to obtain the formed workpiece 100, and completing the flash-free precise forming process, so that the utilization rate of raw materials is high.
(4) The upper mold core 6 and the upper mold stress ring 7 are moved upwards to separate from the upper half part (namely the thin skirt part) of the formed workpiece 100, the inner diameter side of the upper mold stress ring 7 is provided with draft angle, the demolding is easy, the inner diameter side of the lower mold sleeve 9 is not provided with draft angle, the formed workpiece 100 can be held tightly, and the formed workpiece 100 does not return along with the upper mold stress ring 7.
(5) After the upper die stress ring 7 returns and is separated from the formed workpiece 100, the lower die core 8 forcefully ejects the formed workpiece 100 from the lower die sleeve 9 under the action of the lower main ejector rod 10, and then is taken out by a mechanical arm or a manual clamp. If the cavity structure of the lower mold core 8 is complex, the manipulator or the hand pliers cannot take out, a circular plane end face ejector rod is generally arranged in the middle of the lower mold core 8, and the formed workpiece 100 is directly ejected.
According to the invention, by arranging the upper mold core 6 and the upper mold stress ring 7 which move relatively, in the forging forming process, the upper mold core 6 is firstly contacted with a blank to perform impact forging deformation, then a closed cavity is formed, the upper mold core 6 is continuously pressed down in the closed cavity, so that the blank is reversely extruded to be filled in the closed cavity, the forging processing of the blank can be completed by utilizing the multiple deformation processes of first impact forging deformation and then extrusion deformation in the one-time forging forming process, the blocking forging forming processing of the forged steel piston skirt can be realized, and the forming precision is ensured. In addition, in the primary forging precision forming process, the forging forming is firstly carried out in a preliminary blocking mode, then in a closed space, the upper die core 6 carries out secondary extrusion forming on the blank, the forming process of the piston skirt is completed, the existing forging steps of pre-forging and final forging are reduced into one step, the pre-forging and final forging of the forged steel piston skirt can be completed on one set of die at one station, the service life of the die is not influenced, and the die cost is greatly reduced.
In order to ensure the one-time forging forming process, accurate design needs to be carried out on parameters such as the cavity of the die and the volume of the blank, and a computer numerical simulation technology can be adopted to determine the die structure and the die cavity optimization result. Specifically, the forming die 200 digital-analog and blank digital-analog are simplified into numerical simulation software, for example, metal forming simulation software is adopted to perform process simulation, calculation simulation is performed after simulation setting is completed according to actual production setting equipment conditions, production process parameters, forging environment temperature, blank grid division and the like, simulation results are analyzed, and according to a simulation structure, die design before optimization is performed, simulation verification is performed again, and the process is repeated until a theoretical ideal simulation state is obtained, so that a final die structure and a final die cavity optimization result are determined.
In the step (1), when placing the blank, the blank can be placed by a manual clamp and a manipulator, specifically, when the blank is clamped by the manual clamp, the blank is placed on the lower die core 8 and can be positioned only by means of the inner diameter of the lower die sleeve 9, so that the mode has a severe requirement on the blank, the diameter of the blank is required to meet the requirement that the diameter of the blank is smaller than the inner diameter of the lower die sleeve 9 or smaller than a circular groove of a middle cavity of the lower die core 8 after heating, and a gap of 0.5-1 mm is generally reserved on one side. When the manipulator is used for clamping the blank, the center of the blank on the lower die core 8 is completely positioned by the manipulator setting, the diameter of the blank is only smaller than the inner diameter of the lower die sleeve 9, the height-diameter ratio of the blank must meet the automatic feeding requirement (more than or equal to 1.3) and the requirement that extrusion cannot bend and crack (less than or equal to 2.5) at the same time, and the diameter of the blank is more, and the limitation is smaller.
In the step (1), the blank can be placed on the lower die core 8 by clamping with a mechanical arm or a manual clamp, and the blank placement position is limited by the inner diameter of the lower die sleeve 9 or a circular groove of the middle cavity of the lower die core 8, so that the blank is positioned and placed.
As shown in fig. 1 to 6, the present invention further provides a forged steel piston skirt forming die 200, comprising an upper die assembly and a lower die assembly, wherein the upper die assembly comprises an upper die stress ring 7 and an upper die core 6 slidably arranged in the upper die stress ring 7, the lower die assembly comprises a lower die sleeve 9 and a lower die core 8 slidably arranged in the lower die sleeve 9, and the upper die core 6, the lower die core 8, the upper die stress ring 7 and the lower die sleeve 9 can enclose a closed cavity for forging forming, and the closed cavity gradually changes along with the movement of the upper die core 6. The upper mold core 6 is used for bearing the pressure of the inner slide block 1 of the press, and the upper mold stress ring 7 is used for bearing the pressure of the outer slide block 2 of the press.
The inner diameter side of the upper die stress ring 7 can be provided with a draft angle and provided with a step or an arc, wherein the step is shown in fig. 4, and when the upper die core 6 moves upwards, the formed workpiece 100 can not move along with the movement of the upper die core 6 under the blocking of the step or the arc, so that the formed workpiece 100 and the upper die core 6 can be smoothly demolded. The inner diameter side of the lower die sleeve 9 is not required to be provided with a draft angle, and when the upper die stress ring 7 moves upwards, the clamping force can be formed by the lower die sleeve 9 to act together with the draft angle of the upper die stress ring 7, so that the movement along with the movement of the upper die stress ring 7 is avoided, and the smooth demoulding of the formed workpiece 100 and the upper die stress ring 7 is realized.
The top of the upper mold core 6 can be provided with a flange, a reset spring 5 is abutted between the bottom surface of the flange and the top surface of the upper mold stress ring 7, the reset spring 5 can be compressed when the upper mold core 6 moves downwards, and the upper mold core 6 can move upwards smoothly when the inner slide 1 moves upwards through the arrangement of the reset spring 5, so that the upper mold core 6 can be ensured to be separated from the forming workpiece 100 smoothly. And the resetting 5 can select proper specification and model according to the demolding force calculation and the practical experience requirement.
The outside of last mold core 6 can be provided with limit stop 3, and limit stop 3 top is provided with the through-hole that runs through interior slider 1, and the bottom of limit stop 3 is connected on last mould stress ring 7, and limit stop 3 can be with the flange limit of last mold core 6 in certain movable range, avoids making last mold core 6 break away from the upper die subassembly under reset spring 5's effect.
The external diameter side of last mould stress ring 7 can overlap to establish the internal diameter side at last die sleeve 4, and the external diameter side of last mould stress ring 7 and the internal diameter side of last die sleeve 4 are provided with the tapering of matching, and at this moment, the external diameter side of last mould stress ring 7 establishes the internal diameter side at last die sleeve 4 through the tapering cover, can make last mould stress ring 7 and go up die sleeve 4 conical surface interference fit and be connected, when last mould stress ring 7 appears wearing and tearing, crackle, ageing etc. unrepairable defect, can conveniently change last mould stress ring 7.
For the positions of the formed forged steel piston skirt corresponding to the upper mold core 6 and the lower mold core 8, the upper mold core 6 can be made to correspond to the opening direction of the formed forged steel piston skirt, and the lower mold core 8 can be made to correspond to the non-opening direction of the formed forged steel piston skirt with the circular arc grooves.
The principles and embodiments of the present invention have been described in detail with reference to specific examples, which are provided to facilitate understanding of the method and core ideas of the present invention; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (8)
1. The forging steel piston skirt forming method is characterized by comprising an upper die assembly and a lower die assembly, wherein the upper die assembly comprises an upper die stress ring and an upper die core which is arranged in the upper die stress ring in a sliding manner, the lower die assembly comprises a lower die sleeve and a lower die core which is arranged in the lower die sleeve in a sliding manner, the upper die core, the lower die core, the upper die stress ring and the lower die sleeve can enclose a closed cavity for forging forming, the upper die core is used for bearing the pressure of an inner sliding block of a press, and the upper die stress ring is used for bearing the pressure of an outer sliding block of the press;
the method comprises the following steps:
(1) Placing the prepared blank on a lower mold core in a lower mold sleeve;
(2) The upper die core is contacted with the blank firstly, impact forging is carried out on the blank, so that the blank is forged, deformed, and enlarged in diameter, and gradually contacted with the upper die stress ring, the upper die stress ring is closed with the lower die sleeve along with the process, the upper die core, the upper die stress ring, the lower die sleeve and the lower die core form a closed cavity, and the blank is positioned in the closed cavity;
(3) Continuously pressing down the upper mold core, reversely extruding the blank to form and filling the closed cavity to obtain a formed workpiece;
(4) The upper mold core and the upper mold stress ring are moved upwards to separate from the forming workpiece;
(5) The lower die core is moved upwards, and the formed workpiece is ejected out of the lower die sleeve;
the outer diameter side of the upper die stress ring is sleeved on the inner diameter side of the upper die sleeve, and the outer diameter side of the upper die stress ring and the inner diameter side of the upper die sleeve are provided with matched taper.
2. A method of forming a forged steel piston skirt according to claim 1, wherein: and determining the die structure and the die cavity optimization result by adopting a computer numerical simulation technology.
3. A method of forming a forged steel piston skirt according to claim 2, wherein: the aspect ratio of the blank prepared in the step (1) is more than or equal to 1.3 and less than or equal to 2.5.
4. A method of forming a forged steel piston skirt according to claim 3, wherein: in the step (1), the blank is placed on the lower die core by clamping with a mechanical arm or a manual clamp, and the blank placement position is limited by the inner diameter of the lower die sleeve or a circular groove of a cavity in the middle of the lower die core, so that the positioning and placement of the blank are completed.
5. A method of forming a forged steel piston skirt according to claim 1, wherein: the inner diameter side of the upper die stress ring is provided with a draft angle, a step or an arc is arranged on the inner diameter side of the lower die sleeve, and the draft angle is not arranged on the inner diameter side of the lower die sleeve.
6. The forged steel piston skirt forming method according to claim 5, wherein: the top of the upper mold core is provided with a flange, and a return spring is abutted between the bottom surface of the flange and the top surface of the upper mold stress ring.
7. The forged steel piston skirt forming method according to claim 6, wherein: the outside of going up the mold core is provided with limit stop, limit stop top is provided with the through-hole that runs through interior slider, limit stop's bottom is connected go up the mould stress ring.
8. The forged steel piston skirt forming method according to claim 6, wherein: the upper mold core corresponds to the opening direction of the formed forged steel piston skirt.
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| CN117340191A (en) * | 2023-06-19 | 2024-01-05 | 安徽海立汽车零部件有限公司 | A forging mold and process for high-pressure piston |
| CN117960982B (en) * | 2024-04-02 | 2024-06-04 | 江苏理研科技股份有限公司 | Forging processing technology of end face spline |
| CN118477968B (en) * | 2024-06-13 | 2024-10-22 | 郑州煤机格林材料科技有限公司 | Forging die for producing guide sleeve by utilizing pipe |
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