Forming method and forming device for high-torsion-degree blade

Abstract

The invention provides a forming method and device for a high-torsion-degree blade, and belongs to the technical field of pipe machining. The forming method comprises the steps that firstly, a tubular blank is filled with low-melting-point metal to form a solid pipe, then the solid pipe is extruded into a preformed blade with cambered surfaces on the two sides through a preforming device, projections of all the cross sections of the preformed blade coincide in the longitudinal direction, and the preformed blade is formed. The method comprises the following steps: pre-forming a blade, respectively clamping two longitudinal ends of the pre-formed blade by adopting a torsion forming device, enabling the two longitudinal ends to relatively rotate so as to twist the blade, correcting the shape of the twisted blade by adopting a shape correcting device, and finally melting the low-melting-point metal to obtain the high-torsion-degree blade. Compared with an existing forming process, the overall deformation process only comprises extrusion, torsion and shape correction, the forming process is simplified, the machining efficiency can be improved, the low-melting-point metal and the tubular blank are compounded from the beginning, and the material buckling problem in the subsequent forming process is avoided.

Description

Technical Field

[0001] The invention relates to a forming method and a forming device for a high-twist blade, belonging to the technical field of pipe processing. Background Art

[0002] Blades are core components of aircraft engines, gas turbines and other equipment. Blades need to work reliably for a long time under extremely harsh conditions of high temperature, high pressure, high speed and alternating load, and their mechanical properties and fatigue properties need to meet service requirements. At the same time, in order to meet the aerodynamic requirements of blade movement, their structure is usually a spatial thin-walled surface with a local small curvature radius.

[0003] Traditional processing methods for blades include casting, machining, and extrusion. Casting is the process of injecting molten metal into a blade mold, controlling its cooling and solidification process, and finally obtaining the desired blade parts. This method has high production efficiency, but is prone to incomplete filling, and the toughness and fatigue strength of cast blades are limited. Machining is the process of removing material from a block metal billet using a milling cutter or other tool on a machining center to obtain blade parts. This method is difficult to achieve the forming of shell blades with a torsion angle. Extrusion is the process of squeezing a block metal billet into a blade mold using a press to obtain the desired blade parts. This forming process is prone to causing compression holes, folds, or microcracks in the blades, and it is difficult to form blade parts with high torsion. In addition, both casting and extrusion methods produce solid parts, and subsequent material removal is required to form hollow blades, which makes processing very difficult.

[0004] In recent years, many new blade processing methods have emerged, such as a hydraulic forming process for hollow stationary blades of a steam turbine disclosed in a Chinese invention patent application with application publication number CN112621140A. The forming process is to first bend the metal sheet blank, then press the free end of the metal sheet blank to form a hollow blank, then weld the pressed part, and then use a plugging part to seal the two sides of the hollow blank, and inject high-pressure liquid into the hollow blank through the plugging part to perform bulging processing to obtain a semi-finished blade, and finally perform fine processing and remove the plugging part. This method requires reliable sealing of high-pressure liquid and precise control of pressure. The process control is difficult. Excessive pressure will burst the weld and the plugging part. Too low pressure cannot ensure sufficient filling of the local small curvature profile, and the dimensional accuracy of the formed part cannot meet the design requirements. In addition, this method requires a special hydraulic loading device, and cannot be produced with the help of general pressure forming equipment, and the cost is high.

[0005] The Chinese invention patent application with application publication number CN111673397A discloses a forming process for a wide chord hollow blade, which includes: rolling and welding a sheet material to form a tubular blank; closing the tubular blank on a closing device to adjust the radial size of the tubular blank; performing a first stamping pre-forming on the closed tubular blank to form a first preform with small fillets on both sides; filling the first preform with wax and performing a second stamping pre-forming to form a second preform; filling the second preform with wax and performing a third stamping pre-forming to form a third preform; pouring a low melting point alloy into the third preform to form a preform, and twisting the preform on a forming device to obtain a formed blade.

[0006] The above forming process uses sheet metal as raw material, and the sheet metal is rolled and welded to form a tubular blank. Since it undergoes multiple stamping preforming and final torsion forming (torsion forming is actually also a stamping forming), there is a risk of cracking in any forming process of the welding part, and the risk of product scrapping is high. At the same time, the forming process of this process is relatively complicated, and it needs to undergo multiple stamping preforming. The mold must be replaced for each stamping preforming, and the processing efficiency is very low. In addition, during the first stamping preforming, there is no support inside the tubular blank, and it is easy to bend inward when subjected to force. Even if wax is filled inside the molded part before the second and third stamping preforming, the support effect of the wax is very poor, and the molded part still has the risk of inward bending. Therefore, the processing quality of this process is difficult to guarantee. In addition, for high-torsion blades, the stamping punch and die also have complex curved surface structures, and the stamping force is difficult to fully act on the normal direction of the blade surface, and the accurate mold attachment of the high-torsion blade cannot be guaranteed, and the shape and size accuracy of the formed part are poor. Summary of the invention

[0007] The object of the present invention is to provide a forming method for high-twist blades to solve the problems that the existing forming process requires multiple stamping pre-forming, resulting in a complicated process, low processing efficiency, poor shape and size accuracy, and the lack of any support inside the tubular blank during the first stamping pre-forming, which causes the tubular blank to easily bend inward when subjected to force, and the poor supporting effect of the wax during the second and third stamping pre-forming, resulting in the risk of the molded part bending inward and the difficulty in ensuring the processing quality; the object of the present invention is also to provide a forming device for high-twist blades to solve the above problems.

[0008] In order to achieve the above-mentioned purpose, the forming method of the high-twist blade in the present invention adopts the following technical scheme: The forming method of high-twist blades includes first filling a low-melting-point metal with a melting point lower than that of the tubular blank to form a solid tube, then placing the solid tube into a preforming device, and extruding the solid tube into a preformed blade with curved surfaces on both sides through the preforming device, wherein the longitudinal projections of the cross sections of the preformed blades are overlapped, and then using a twisting forming device to clamp the longitudinal ends of the preformed blades respectively and make the longitudinal ends rotate relatively to cause the blades to twist and deform, and then using a shaping device to shape the twisted blades, and finally melting the low-melting-point metal to obtain high-twist blades.

[0009] The beneficial effect of the above technical solution is that: the present invention is a pioneering invention. First, a low-melting-point metal with a melting point lower than that of the tubular blank is filled in the tubular blank to form a solid tube. Then, the solid tube is placed in a preforming device. The solid tube is extruded into a preformed blade with curved surfaces on both sides by the preforming device. During the extrusion process, the low-melting-point metal can be deformed freely after being compressed and flows out from the tube end. The flow deformation resistance of the low-melting-point metal is the pressure inside the tube. The direction of the friction force of the low-melting-point metal on the inner wall of the tube is the same as the direction of the flow of the tube material. This friction can assist the material flow, avoid excessive local thinning of the tube, avoid inward bending of the tube, and improve the uniformity of the thickness of the tube. At the same time, the cross-sections of the preformed blades overlap in the longitudinal direction, and the preforming requirements before twisting are met by one extrusion. Then, a twisting forming device is used to clamp the longitudinal ends of the preformed blade respectively and make the longitudinal ends rotate relative to each other to cause the blade to twist and deform, so as to achieve the basic shape of the required blade. Then, a correction device is used to correct the shape of the twisted blade to ensure the shape and size accuracy of the blade. Finally, the low-melting-point metal is melted away to obtain high-twist blades.

[0010] Compared with the existing forming process, the overall deformation process of the present invention only includes extrusion, twisting and shaping, the forming process is simplified, the processing efficiency can be improved, and the low-melting-point metal is compounded with the tubular blank from the beginning to avoid the material buckling problem in the subsequent forming process, reduce the difficulty of process control, and make it easier to ensure the processing quality.

[0011] Furthermore, the tubular blank is a seamless tube.

[0012] In order to achieve the above-mentioned purpose, the forming device of the high-twist blade in the present invention adopts the following technical scheme: A forming device for high-twist blades includes a preforming device, a twisting forming device and a shaping device. The preforming device includes an extrusion punch and an extrusion die. The extrusion punch and the extrusion die respectively have extrusion arc surfaces whose projections of cross sections at various locations in the longitudinal direction overlap, so as to extrude a solid tube filled with a low-melting-point metal into a preformed blade with arc surfaces on both sides; the twisting forming device includes two clamping modules for clamping the longitudinal ends of the preformed blade and a driving mechanism for driving at least one clamping module to rotate so that the two ends of the blade rotate relative to each other and thus cause the blade to twist and deform; the shaping device includes a shaping punch and a shaping die. The shaping punch and the shaping die have shaping surfaces that are adapted to the final product, so as to shape the twisted blade into a qualified product.

[0013] The beneficial effect of the above technical scheme is that: the present invention is a pioneering invention, the forming device of the high-torsion blade includes a preforming device, a torsion forming device and a correction device, wherein the preforming device includes an extrusion punch and an extrusion die, the extrusion punch and the extrusion die respectively have an extrusion arc surface with the projections of the cross sections at each location in the longitudinal direction all overlapping, and are used to extrude a solid tube filled with a low-melting-point metal into a preformed blade with arc surfaces on both sides, the low-melting-point metal can be freely deformed and flow out from the tube end after being compressed during the extrusion process, the flow deformation resistance of the low-melting-point metal is the pressure inside the tube, the direction of the friction force of the low-melting-point metal on the inner wall of the tube is the same as the direction of the flow of the tube material, this friction can assist the material flow, avoid excessive local thinning of the tube, avoid inward bending of the tube, and improve the uniformity of the thickness of the tube. At the same time, since the extrusion punch and the extrusion die respectively have an extrusion arc surface with the projections of the cross sections at each location in the longitudinal direction all overlapping, the projections of the cross sections at each location of the preformed blade in the longitudinal direction also overlap, so that the preforming requirements before torsion can be met by one extrusion.

[0014] The twist forming device includes two clamping modules for clamping the longitudinal ends of the preformed blade and a driving mechanism for driving at least one clamping module to rotate so that the two ends of the blade rotate relative to each other and thus cause the blade to twist and deform. The basic shape of the required blade can be achieved through the twist forming device. The shape correction device includes a shape correction punch and a shape correction die. The shape correction punch and the shape correction die have a shape correction surface that matches the final product to correct the twisted blade into a qualified product and ensure the shape and size accuracy of the blade.

[0015] In summary, compared with the existing forming process, the overall deformation process of the present invention only includes extrusion, torsion and correction, the forming process is simplified, the processing efficiency can be improved, and the low-melting-point metal is compounded with the tubular blank from the beginning to avoid the problem of material buckling in the subsequent forming process, reduce the difficulty of process control, and make it easier to ensure the processing quality.

[0016] Furthermore, the clamping module among the two clamping modules that is driven to rotate by the driving mechanism is a rotating clamping module, and the torsion forming device includes a base plate and a bearing bracket fixed on the base plate, a bearing is installed on the bearing bracket, the outer ring of the bearing is interference fit with the inner hole on the bearing bracket, a torsion disk is fixed on the inner ring of the bearing, the torsion disk is connected to the driving mechanism, and the rotating clamping module is installed on the torsion disk.

[0017] Furthermore, one of the two clamping modules is a rotating clamping module driven to rotate by a driving mechanism, and the other is a fixed clamping module. The torsion forming device includes a bottom plate and a base fixed on the bottom plate, and the fixed clamping module is installed on the base.

[0018] Furthermore, the two clamping modules each include a pair of separately arranged clamps, and the two clamps in the pair are respectively provided with butt end faces and clamping arc surfaces for matching with the arc surfaces on both sides of the preformed blade, and a clamping cavity is formed between the clamping arc surfaces on both sides.

[0019] Furthermore, the extrusion die is provided with extrusion positioning pins for respectively positioning the two longitudinal ends of the solid pipe during the extrusion process of the solid pipe.

[0020] Furthermore, the shaping die is provided with shaping positioning pins for respectively positioning the longitudinal ends of the blade during the shaping process.

[0021] Furthermore, the power source of the driving mechanism is a servo motor to drive the clamping module to rotate at a certain angle and speed.

[0022] Furthermore, positioning holes for positioning the clamping modules are respectively provided on the two clamping modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A three-dimensional view of a tubular blank in an embodiment of a forming device for a high-twist blade of the present invention; Figure 2 It is a three-dimensional view of a tubular blank filled with a low-melting-point metal in an embodiment of a forming device for a high-twist blade of the present invention; Figure 3 It is a top view of a tubular blank after being filled with a low melting point metal in an embodiment of a forming device for a high twist blade of the present invention; Figure 4 It is a front view cutaway diagram of a tubular blank after being filled with a low melting point metal in an embodiment of a forming device for a high twist blade of the present invention; Figure 5 This is a diagram showing the use state of the preforming device in the embodiment of the forming device for high-twist blades of the present invention at time t0; Figure 6This is a diagram showing the use state of the preforming device in the embodiment of the forming device for high-twist blades of the present invention at time t1; Figure 7 This is a diagram showing the use state of the preforming device in the embodiment of the forming device for high-twist blades of the present invention at time t2; Figure 8 for Figure 5~Figure 7 A three-dimensional diagram of the extrusion punch and extrusion die; Fig. 9 A three-dimensional diagram of a preformed blade formed by a preformer in an embodiment of a forming device for a high-twist blade of the present invention; Fig.10 A three-dimensional diagram of a twist forming device from one perspective in an embodiment of a forming device for a blade with a high twist degree of the present invention; Fig.11 A three-dimensional diagram of a twist forming device from another perspective in an embodiment of a forming device for a blade with a high twist degree of the present invention; Fig.12 for Fig.10 and Fig.11 The coordination diagram of the two clamping modules and the preformed blades; Fig.13 It is a structural diagram of a shaping device in an embodiment of a shaping device for high-twist blades of the present invention; Fig.14 for Fig.13 A three-dimensional view of the center shaping punch and shaping die; Fig.15 It is a three-dimensional view of the final product of the forming device for high-twist blades in the embodiment of the present invention.

[0024] In the figure: 1. tubular blank; 2. low melting point metal; 3. extrusion lower template; 4. extrusion guide pin; 5. extrusion guide sleeve; 6. extrusion upper template; 7. first screw; 8. extrusion punch; 8-1. extrusion arc surface of punch; 8-2. extrusion fitting surface of punch; 9. solid pipe; 10. extrusion positioning pin; 11. extrusion die; 11-1. extrusion arc surface of die; 11-2. extrusion fitting surface of die; 12. second screw; 13. rotary clamping module; 13-1. rotary chuck; 14. base; 15. first positioning pin; 16. third screw; 17. bearing outer ring; 18. bearing; 19. bearing bracket; 20. bearing inner ring; 21. torque Turntable; 22. Connecting shaft; 23. Servo motor; 24. Spacer; 25. Bottom plate; 26. Preformed blades; 27. Fourth screw; 28. Second locating pin; 29. ​​Fixed clamping module; 29-1. Fixed chuck; 30. Fifth screw; 31. Correction punch; 31-1. Correction curved surface of punch; 31-2. Correction fitting surface of punch; 32. Twisted blades; 33. Correction locating pin; 34. Correction die; 34-1. Correction curved surface of die; 34-2. Correction fitting surface of die; 35. Correction lower template; 36. Correction guide column; 37. Correction guide sleeve; 38. Correction upper template; 39. Sixth screw; 40. Final product. DETAILED DESCRIPTION

[0025] In view of the technical problems existing in the prior art, the basic concept of the present invention is to compound the low-melting-point metal with the tubular blank from the very beginning to avoid the problem of material buckling in the subsequent forming process, while reducing the intermediate forming steps so that the deformation process only includes extrusion, torsion and shaping, thereby simplifying the forming process and improving processing efficiency.

[0026] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0027] Embodiment 1 of the forming device of the high twist blade of the present invention: The forming device of the high-twist blade comprises a preforming device, a twist forming device and a shape correction device. The three forming devices are used in sequence to form a high-twist blade that meets the requirements. Before using the preforming device, first obtain the following Figure 1 The tubular blank 1 shown in the embodiment is a seamless tube, which is not easy to crack during the subsequent deformation process, reducing the risk of product scrapping. The wall thickness of the seamless tube is 0.1-1.5 mm, and it can be obtained by directly cutting the commercially available high-temperature alloy tube. The material of the high-temperature alloy tube can be titanium alloy, cobalt-based high-temperature alloy, nickel-based high-temperature alloy or austenitic stainless steel, etc., among which the titanium alloy grade can be TA1 or TA2, the cobalt-based high-temperature alloy grade can be GH5188, the nickel-based high-temperature alloy grade can be GH3044 or GH4169, and the austenitic stainless steel grade can be 201, 304 or 316.

[0028] like Figure 2 , Figure 3 and Figure 4 As shown, a low-melting-point metal 2 having a melting point lower than that of the tubular blank 1 needs to be filled in the tubular blank 1 to form a solid tube 9. The melting point of the low-melting-point metal 2 is generally 60 to 200°C, and the main components are one or more of bismuth, cadmium, tin, lead, dysprosium, and indium, preferably multiple, to form different eutectic low-melting-point alloys. In this embodiment, a bismuth-tin alloy with 58% bismuth and 42% tin can be used.

[0029] The filling method of the low melting point metal 2 is to first heat and melt it, and then pour it into the tubular blank 1. After cooling, a solid tube 9 can be obtained. Both ends of the solid tube 9 are open to facilitate the flow of the low melting point metal 2 in the subsequent forming process.

[0030] like Figure 5 , Figure 6 and Figure 7 As shown, the preforming device includes an extrusion upper template 6 and an extrusion lower template 3. An extrusion guide sleeve 5 is fixed to the extrusion upper template 6, and an extrusion punch 8 is fixed to the extrusion upper template 6 by a first screw 7. An extrusion guide post 4 is fixed to the extrusion lower template 3, and the extrusion guide post 4 is inserted into the extrusion guide sleeve 5, and the two are guided and matched in the up and down directions. An extrusion die 11 is also fixed to the extrusion lower template 3 by a second screw 12, and the extrusion die 11 and the extrusion punch 8 respectively have an extrusion arc surface for extruding the solid pipe 9. Figure 8 As shown, the extrusion arc surface on the extrusion punch 8 is the punch extrusion arc surface 8-1, and the extrusion arc surface on the extrusion die 11 is the die extrusion arc surface 11-1. The punch extrusion arc surface 8-1 and the die extrusion arc surface 11-1 are both parts of the cylindrical surface. The cross section of each extrusion arc surface (the cross section is perpendicular to the axis of the cylindrical surface) is longitudinal ( Figure 5~Figure 7 The projections on the direction perpendicular to the paper surface in the figure are all coincident, and the solid tube 9 filled with the low melting point metal 2 can be extruded into a preformed blade 26 with curved surfaces on both sides ( Fig. 9 As shown in FIG. 1 ), the projections of the cross sections of the preformed blade 26 in the longitudinal direction also coincide.

[0031] At the same time, the curvature radius of the male die extrusion arc surface 8-1 and the female die extrusion arc surface 11-1 are different, and the curvature radius of the male die extrusion arc surface 8-1 is greater than the curvature radius of the female die extrusion arc surface 11-1, so that the cross section of the preformed blade 26 is crescent-shaped. Figure 8As shown, the extrusion punch 8 is provided with a punch extrusion fitting surface 8-2 on both sides of the punch extrusion arc surface 8-1, and the extrusion die 11 is provided with a die extrusion fitting surface 11-2 on both sides of the die extrusion arc surface 11-1. The punch extrusion fitting surface 8-2 and the die extrusion fitting surface 11-2 are used for docking to limit the degree of extrusion.

[0032] When squeezing, first Figure 5 As shown, the solid pipe 9 is placed on the extrusion arc surface 11-1 of the extrusion die 11, and then the press drives the extrusion upper template 6 to move downward at a certain speed, so that the extrusion punch 8 contacts and gradually compresses the solid pipe 9, as shown in FIG. Figure 6 and Figure 7 As shown, until the punch extrusion fitting surface 8-2 and the die extrusion fitting surface 11-2 fit together. During the continuous downward pressing of the extrusion punch 8, the low-melting-point metal can be deformed freely and flow out from the tube end after being pressed. The flow deformation resistance of the low-melting-point metal is the pressure inside the tube. The direction of the friction force of the low-melting-point metal on the inner wall of the tube is the same as the direction of the flow of the tube material. This friction can assist the material flow, ensure the synchronization of the deformation of the low-melting-point metal and the tube, avoid excessive thinning of the tube caused by the low-melting-point metal flowing too fast, avoid the tube from bending inward, and improve the uniformity of the tube thickness. At the same time, since the mechanical properties of low-melting-point metals can be selected in a large range, low-melting-point metals with different mechanical properties can be selected according to the mechanical properties of the processed tube to match the deformation and material flow of the tube.

[0033] In addition, during the extrusion process, in order to position the solid tube 9, extrusion positioning pins 10 are provided on the extrusion die 11 for positioning the two longitudinal ends of the solid tube 9 respectively. The two extrusion positioning pins 10 are both located at the lowest point of the die extrusion arc surface 11-1, and the upper ends both protrude from the die extrusion arc surface 11-1, but the protruding height is less than the size of the thickest position of the preformed blade 26, so as to avoid the extrusion positioning pins 10 interfering with the downward movement of the extrusion punch 8.

[0034] The twist forming device includes two clamping modules for clamping the longitudinal ends of the preformed blade 26, and also includes a driving mechanism such as Fig.10 and Fig.11 As shown, one of the two clamping modules is a rotating clamping module 13 driven by a driving mechanism, and the other is a fixed clamping module 29. When the rotating clamping module 13 rotates, the two ends of the preformed blade 26 rotate relative to each other, so that the blade can be twisted and deformed to achieve the basic shape of the desired blade, and obtain a product that is very close to the final product 40 ( Fig.15 Parts with curved surfaces (as shown).

[0035] Specifically, the torsion forming device includes a base plate 25, a bearing bracket 19 is fixed on the base plate 25, a bearing 18 is installed on the bearing bracket 19, the bearing outer ring 17 of the bearing 18 is interference fit with the inner hole of the bearing bracket 19, a torsion disk 21 is fixed on the bearing inner ring 20 of the bearing 18, the torsion disk 21 is circular and interference fits with the bearing inner ring 20, the torsion disk 21 is connected to the driving mechanism, and the rotary clamping module 13 is installed on the torsion disk 21. The power source of the driving mechanism is a servo motor 23, a cushion block 24 is fixed on the base plate 25, and the servo motor 23 is fixed on the cushion block 24. The output end of the servo motor 23 is transmission-connected with a connecting shaft 22, and the other end of the connecting shaft 22 is connected to the torsion disk 21, which is used to drive the torsion disk 21 to rotate.

[0036] Both clamping modules include a pair of separately arranged clamps to facilitate the clamping of the preformed blade 26 before twisting and the demoulding after twisting. Fig.12 As shown, the two chucks of the rotating clamping module 13 are rotating chucks 13-1, and the two rotating chucks 13-1 are respectively fixed on the torsion disk 21 by third screws 16. At the same time, each rotating chuck 13-1 is respectively provided with a first positioning hole. When installing the rotating chuck 13-1, the rotating chuck 13-1 is first positioned by the first positioning pin 15 on the torsion disk 21, and then the screws are tightened, which is convenient for installation.

[0037] The base 14 is also fixed on the bottom plate 25, and the base 14 is arranged opposite to the bearing bracket 19, and the fixed clamping module 29 is installed on the base 14. Specifically, the two clamps of the fixed clamping module 29 are fixed clamps 29-1, and the two fixed clamps 29-1 are respectively fixed on the base 14 by fourth screws 27, and each fixed clamp 29-1 is provided with a second positioning hole. When installing the fixed clamp 29-1, the fixed clamp 29-1 is first positioned by the second positioning pin 28 on the base 14, and then the screws are tightened, which is convenient for installation.

[0038] like Fig.12 As shown, the two rotating clamps 13-1 of the rotating clamping module 13 and the two fixed clamps 29-1 of the fixed clamping module 29 are respectively provided with butt end faces and clamping arc surfaces for matching with the arc surfaces on both sides of the preformed blade 26, and a clamping cavity is formed between the clamping arc surfaces on both sides, so that the outer peripheral surfaces at both ends of the preformed blade 26 can be better fitted to avoid other deformations at both ends of the preformed blade 26 during the torsional deformation process. At the same time, the two clamps have butt end faces, which facilitates the positioning between the two clamps and the subsequent installation.

[0039] When using the twist forming device, firstly, the two rotating chucks 13-1 of the rotating clamping module 13 and the two fixed chucks 29-1 of the fixed clamping module 29 are opened respectively, and the two ends of the preformed blade 26 are placed on a rotating chuck 13-1 and a fixed chuck 29-1 respectively, and then the other rotating chuck 13-1 and the other fixed chuck 29-1 are closed, and the two rotating chucks 13-1 are fixed to the torsion disk 21 respectively by the third screw 16, and the two fixed chucks 29-1 are fixed to the base 14 respectively by the fourth screw 27, that is, the installation of the preformed blade 26 is completed. Then, the servo motor 23 is connected to the AC power supply, and the pulse frequency is controlled in the AC servo working system to quantitatively control the rotation speed and angle of the servo motor 23, so as to control the connecting shaft 22, the torsion disk 21, and the rotating clamping module 13 to rotate at a certain angle and speed, and apply torque to the preformed blade 26, so as to achieve torsional deformation of the preformed blade 26 at a certain angle and speed, and promote the forming of high-torsion blades. The servo motor 23 drives the connecting shaft 22 to rotate at a speed of 1° / s, and the total torsion angle is no greater than 90°.

[0040] like Fig.13 As shown, the shaping device includes a shaping upper template 38 and a shaping lower template 35. A shaping guide sleeve 37 is fixed to the shaping upper template 38, and a shaping punch 31 is fixed to the shaping upper template 38 by a fifth screw 30. A shaping guide post 36 is fixed to the shaping lower template 35, and the shaping guide post 36 is inserted into the shaping guide sleeve 37, and the two guide and cooperate in the up and down directions. A shaping concave mold 34 is also fixed to the shaping lower template 35 by a sixth screw 39. The shaping concave mold 34 and the shaping punch 31 respectively have a shaping curved surface adapted to the final product 40, and the final product 40 is formed by the shaping lower template 35. Fig.14 As shown, the shaping surface on the shaping die 34 is the die shaping surface 34-1, and the shaping surface on the shaping punch 31 is the punch shaping surface 31-1, and the two cooperate to shape the twisted blade 32 into a qualified product.

[0041] In addition, the correction die 34 is provided with a die correction fitting surface 34-2 on both sides of the die correction curved surface 34-1, and the correction punch 31 is provided with a punch correction fitting surface 31-2 on both sides of the punch correction curved surface 31-1, for controlling the correction accuracy. During the correction process, the correction punch 31 gradually moves downward under the action of the press, contacts with the twisted blade 32 and corrects the shape of the blade until the die correction fitting surface 34-2 and the punch correction fitting surface 31-2 fit, indicating that the blade has been formed.

[0042] In addition, during the shaping process, in order to position the blade, shaping positioning pins 33 for positioning the longitudinal ends of the blade are provided on the shaping die 34. Two shaping positioning pins 33 are provided at each end. The two shaping positioning pins 33 are symmetrically arranged, and the upper ends of the two shaping positioning pins 33 protrude from the shaping surface 34-1 of the die. However, the protruding height is less than the thickness dimension of the corresponding position of the final product to avoid interference of the shaping positioning pins 33 with the downward movement of the shaping punch 31.

[0043] Embodiment 1 of the method for forming a high-twist blade of the present invention: The forming method of the high-twist blade requires the use of the above-mentioned high-twist blade forming device, and the forming method specifically includes the following steps: Step 1: Figure 2~Figure 4 As shown, firstly, a low-melting-point metal 2 having a melting point lower than that of the tubular blank 1 is filled in the tubular blank 1 to form a solid tube 9 .

[0044] Step 2: Figure 5~Figure 7 As shown, the solid tube 9 is then placed into the extrusion die 11 of the preforming device, and the extrusion punch 8 is controlled by the press to move downward to extrude the solid tube 9 into a preformed blade 26 with curved surfaces on both sides ( Fig. 9 As shown in FIG. 1 ), the projections of the cross sections of the preformed blade 26 in the longitudinal direction coincide with each other.

[0045] Step 3: Fig.10 and Fig.11 As shown, two clamping modules of the torsion forming device are used to clamp the longitudinal ends of the preformed blade 26 respectively, and the servo motor 23 is controlled to work. The servo motor 23 drives the torsion disk 21 to rotate through the connecting shaft 22, so that the longitudinal ends of the preformed blade 26 rotate relative to each other, thereby causing the preformed blade 26 to produce torsional deformation at a certain angle and speed, thereby promoting the forming of high-twist blades.

[0046] Step 4: Fig.13 As shown, a shape correction device is used to correct the shape of the twisted blade 32 to ensure the blade size accuracy.

[0047] Step 5: Melt the low melting point metal by heating to obtain the final high twist hollow blade, such as Fig.15 shown.

[0048] In summary, the forming method and forming device of the high-twist blade of the present invention composites the low-melting-point metal with the tubular blank from the beginning to transform it into a metal composite rod, thereby avoiding the buckling problem of the hollow tube under the action of external pressure, improving the stability of metal deformation during the forming process of hollow parts with complex profiles, reducing the difficulty of process control, and making it easier to ensure the processing quality. At the same time, the melting temperature of the low-melting-point metal is much lower than the recrystallization start temperature of the metal tube, which can avoid the metal tube from being heated and softened, and is easy to demold, simplifying the process. The torsion forming device used can quantitatively control the angle and direction of the torsion of the blade by adjusting the angle and speed of the servo motor, thereby improving the reliability of process control. At the same time, compared with the existing forming process, the overall deformation process only includes extrusion, torsion and correction, the forming process is simplified, and the processing efficiency can be improved.

[0049] In other embodiments of the forming method of high-twist blades: the tubular blank may not be a seamless tube, but like the prior art, a plate is used as the raw material, and the plate is rolled and welded to form the tubular blank.

[0050] In other embodiments of the forming device for high-twist blades: positioning holes are no longer required on the two clamping modules, and they can be directly installed and fixed by screws.

[0051] In other embodiments of the forming device for high-twist blades: the power source of the driving mechanism can also be a stepper motor or a rotary hydraulic cylinder or a rotary air cylinder.

[0052] In other embodiments of the forming device for high-twisted blades: the shaping die may no longer be provided with shaping positioning pins, and the twisted blades can be directly placed on the shaping die during shaping.

[0053] In other embodiments of the forming device for high-twist blades: the extrusion positioning pins may no longer be provided on the extrusion die, and the solid tube may be directly placed on the extrusion die during extrusion.

[0054] In other embodiments of the forming device for high-twist blades: the two clamping modules can be integrated clamping blocks. In this case, the clamping cavity has been pre-processed on each clamping block. When in use, the two clamping blocks are respectively mounted on the two ends of the pre-formed blade, and then the two clamping blocks are installed on the twist forming device.

[0055] In other embodiments of the forming device for high-twist blades: the two clamping modules can both be rotating clamping modules, and the two clamping modules are rotatably installed through bearings, torsion plates, and bearing brackets. At this time, the driving mechanism includes two motors, and the two motors are respectively connected to the corresponding torsion plates through connecting shafts. The two motors work simultaneously and rotate in opposite directions to cause the longitudinal ends of the pre-formed blade to rotate relative to each other and produce twisting deformation.

[0056] In other embodiments of the forming device for high-twist blades: no matter how many of the two clamping modules are rotating clamping modules, the installation method of the rotating clamping module may no longer be through the bearing bracket and the bearing. For example, a rotating support frame is directly provided for the rotating clamping module, and a supporting hole is opened on the rotating support frame. The outer diameter of the rotating clamping module is adapted to the inner diameter of the supporting hole, and the rotating clamping module can rotate in the supporting hole. Of course, the torsion disk can be omitted at this time, so that the rotating clamping module can be directly connected to the connecting shaft.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A method for forming a high-twist blade, characterized in that: The method includes first filling a tubular blank with a low-melting-point metal whose melting point is lower than that of the tubular blank to form a solid tube, and then placing the solid tube into a preforming device. The solid tube is extruded into a preformed blade with curved surfaces on both sides by the preforming device, and the longitudinal projections of the cross sections of the preformed blade overlap. Then, a torsion forming device is used to clamp the longitudinal ends of the preformed blade respectively and make the longitudinal ends rotate relatively to each other so as to cause the blade to twist and deform. Then, a shaping device is used to shape the twisted blade. Finally, the low-melting-point metal is melted to obtain a high-twist blade.

2. The method for forming a high-twist blade according to claim 1, characterized in that: The tubular blank is a seamless tube.

3. A forming device for high-twist blades, characterized in that: The invention comprises a preforming device, a twisting forming device and a shaping device. The preforming device comprises an extrusion punch and an extrusion die. The extrusion punch and the extrusion die respectively have extrusion arc surfaces whose projections of cross sections at all places in the longitudinal direction overlap, so as to extrude a solid tube filled with a low-melting-point metal into a preformed blade with arc surfaces on both sides. The twisting forming device comprises two clamping modules for clamping the longitudinal ends of the preformed blade and a driving mechanism for driving at least one clamping module to rotate so that the two ends of the blade rotate relative to each other, thereby causing the blade to be twisted and deformed. The shaping device comprises a shaping punch and a shaping die, and the shaping punch and the shaping die have shaping curved surfaces adapted to the final product so as to shape the twisted blade into a qualified product.

4. The high twist blade forming device according to claim 3 is characterized in that: The clamping module driven to rotate by the driving mechanism among the two clamping modules is a rotating clamping module. The torsion forming device includes a base plate and a bearing bracket fixed on the base plate. A bearing is installed on the bearing bracket. The outer ring of the bearing is interference fit with the inner hole of the bearing bracket. A torsion disk is fixed on the inner ring of the bearing. The torsion disk is connected to the driving mechanism, and the rotating clamping module is installed on the torsion disk.

5. The high twist blade forming device according to claim 3, characterized in that: One of the two clamping modules is a rotating clamping module driven to rotate by a driving mechanism, and the other is a fixed clamping module. The torsion forming device includes a bottom plate and a base fixed on the bottom plate, and the fixed clamping module is installed on the base.

6. The high twist blade forming device according to any one of claims 3 to 5, characterized in that: The two clamping modules each include a pair of separately arranged clamps, wherein the two clamps in the pair are respectively provided with butt end faces and clamping arc surfaces for matching the arc surfaces on both sides of the preformed blade, and a clamping cavity is formed between the clamping arc surfaces on both sides.

7. The high twist blade forming device according to any one of claims 3 to 5, characterized in that: The extrusion die is provided with extrusion positioning pins for positioning the two longitudinal ends of the solid pipe respectively during the extrusion process of the solid pipe.

8. The high twist blade forming device according to any one of claims 3 to 5, characterized in that: The shaping die is provided with shaping positioning pins for positioning the longitudinal ends of the blades respectively during the shaping process.

9. The high twist blade forming device according to any one of claims 3 to 5, characterized in that: The power source of the driving mechanism is a servo motor, which drives the clamping module to rotate at a certain angle and speed.

10. The high twist blade forming device according to any one of claims 3 to 5, characterized in that: The two clamping modules are respectively provided with positioning holes for positioning the clamping modules.

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