A reconfigurable discrete die stretch bending precision forming apparatus and method for use on narrow platforms, and a stretch bending machine.

Abstract

This invention discloses a reconfigurable discrete mold stretch bending precision forming device and its method of use for narrow tabletops, as well as a stretch bending machine. In the forming device, multiple positioning grooves are evenly arranged circumferentially on the upper end face of the front end of the worktable for mounting seats of the front end of the longitudinal moving components. The rear end of the worktable is equipped with the drive mechanism of each longitudinal moving component. Each mounting seat contains one mold component, and the top of the mounting seat is equipped with a mold swing component. The rotation axis of the mold swing component is fixedly connected to the mold component. A single mold component moves to a designated position, deflects at a corresponding angle, and holds. The end faces of each mold component form the theoretical shape of a stringer with different radii through multi-point fitting, and the position of each mold component is locked during the stretch bending forming process of the stretch bending machine, so as to simultaneously complete the stretch bending forming of multiple stringers of an aircraft. The control system is used to control the movement of each group of longitudinal moving components and each mold swing component.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of aircraft manufacturing technology, and particularly to a reconfigurable discrete mold stretch bending precision forming apparatus and method for use on narrow platforms, as well as a stretch bending machine. Background Technology

[0002] Aircraft T-section stringers refer to aircraft-type metal profile parts with a "T"-shaped cross-section and an overall irregular arc shape. They are mainly used for aircraft skin support and fixation to ensure the stability of the aircraft structure. Stretch bending forming technology is a technique for stretching and bending profiles. It has the advantages of high bending forming precision and good forming quality, and has a wide range of applications.

[0003] The aircraft profiles are mainly L-shaped and T-shaped, with nearly two hundred different types. The radius of curvature varies at different locations on the aircraft skin. Each stringer requires a set of traditional special bending molds for forming. The large number of bending molds results in high mold manufacturing costs, high warehouse storage and management costs, and significant transportation costs during storage and retrieval.

[0004] As the number of aircraft models continues to increase, the number of special stringer bending dies also increases. During the production process, for the forming of each stringer, it is necessary to disassemble and install special dies on the corresponding stringer bending machine. Repeated disassembly and installation will cause wear on the stringer bending machine's positioner, which will eventually lead to inaccurate positioning on the stringer bending machine, resulting in stringer parts exceeding tolerances. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned technical problems. The embodiments of this invention provide a reconfigurable discrete mold stretch bending precision forming device and method for narrow tabletops, as well as a stretch bending machine, to solve the problem of existing aircraft stringer stretch bending methods. Since the forming of each stringer usually requires a set of traditional dedicated stretch bending forming molds, the mold manufacturing cost is high, and the frequent disassembly and assembly of the dedicated stringer stretch bending mold on the stretch bending machine causes wear on the stretch bending machine.

[0006] The technical solution of the present invention: In a first aspect, the present invention provides a reconfigurable discrete mold stretch bending precision forming device for narrow tabletops, comprising: a longitudinal moving component 1, a mold component 2, a mold swinging component 3, a worktable 4, and a control system 5;

[0007] The workbench 4 is fixedly installed on the narrow table surface of the bending machine 6. The workbench 4 is configured as a stepped fan ring structure, including a front bending working part located away from the center and a rear mounting part located near the center. The upper surface of the front bending working part is evenly arranged with multiple positioning grooves 42 in the radial direction along the circumference.

[0008] The mounting base 15 of the front end of the longitudinal moving component 1 is installed in each positioning groove 42 of the workbench 4, and the drive mechanism of each longitudinal moving component 1 is installed through the rear mounting part. Each mounting base 15 is equipped with a mold component 2, and the top of the mounting base 15 is equipped with a mold swing component 3. The rotating shaft of the mold swing component 3 passes through the mounting base 15 and is fixedly connected to the mold component 2.

[0009] A single mold assembly 2 is used to move radially to a designated position under the push of its mounted longitudinal moving assembly 1, and deflect by a corresponding angle and maintain the deflection angle under the drive of the connecting shaft of the mold swing assembly 3;

[0010] Under the adjustment of the longitudinal moving components 1 and the mold swinging components 3 on the workbench 4, the end faces of each mold component 2 form the theoretical shape of the stringer with different radii through multi-point fitting, and keep the position of each mold component 2 locked during the bending process of the bending machine 6, and simultaneously complete the bending process of multiple stringers of the aircraft.

[0011] The control system 5 is connected to the drive mechanism in each mold swing assembly 3 and each longitudinal movement assembly 1 respectively. It is used to control each group of longitudinal movement assemblies 1 to move radially to form the overall bending trend of the stringer to be bent, and to control each mold swing assembly 3 to rotate so as to drive the rotation of each mold assembly 2, so that the bending end face of each mold assembly 2 matches the bending profile of each section of the stringer at the corresponding position.

[0012] Optionally, in the reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops as described above,

[0013] The rear end mounting part of the workbench 4 has a fan-shaped annular protrusion 41, and the side of the fan-shaped annular protrusion 41 near the front end bending working part is provided with a fan-shaped mounting step that is lower than the fan-shaped annular protrusion 41.

[0014] Each set of longitudinal moving components 1 includes: a motor 11, an integrated base 12, a self-locking screw structure 13, a slider rail structure 14, and a mounting base 15;

[0015] Among them, the slider rail structure 14 is fixedly installed in the positioning groove 42 at the corresponding position in the workbench 4; the bottom of the mounting seat 15 is a flat plate structure and is fixedly connected to the slider sliding on the rail in the slider rail structure 14; the bottom surface of the integral seat 12 is fixed on the fan-shaped mounting step at the front end of the boss 41 of the workbench 4, and its rear end surface is in close contact with the front side end surface of the boss 41, for resisting the pressure applied during the forming of the aircraft stringer. The motor 11 is installed on the rear end surface of the integral seat 12. The rear end of the self-locking screw structure 13 passes through the integral seat 12 and is connected to the drive shaft of the motor 11. The front end of the self-locking screw structure 13 is fixedly connected to the mounting seat 15 through a nut 131, and drives the mounting seat 15 to move radially along the positioning groove 42 under the drive of the motor 11. Optionally, in a reconfigurable discrete die stretch bending precise forming device for a narrow workbench as described above, the mounting seat 15 includes: a fixed bottom plate, an intermediate vertical plate 151, and a top mounting portion;

[0016] Among them, the mounting seat 15 is installed on the slider of the corresponding rail through the fixed bottom plate. The intermediate vertical plate 151 is vertically arranged in the middle of the fixed bottom plate. A through hole is provided on the intermediate vertical plate 151 for the front end of the self-locking screw structure 13 to pass through the through hole and be fixed by a nut 131. The top mounting portion is set as a "C" - shaped structure 152 for semi - embedded sleeving and installing the die assembly 2 through the "C" - shaped structure 152. A limiting boss 153 for installing the die assembly 2 is provided on the upper surface of the lower end of the "C" - shaped structure 152. Coaxial holes are provided in the upper and lower plates of the "C" - shaped structure 152 in the vertical direction for installing the rotating shaft 35 of the die swing assembly 3.

[0017] Optionally, in a reconfigurable discrete die stretch bending precise forming device for a narrow workbench as described above, each die assembly includes: a die head group 21, multiple groups of replacement part groups 22, and an adjustment and installation plate 23;

[0018] Among them, the die head group 21 includes: a male head 211 and a female head 212 which are installed in a relatively cooperative manner up and down. A through hole is provided at the rear end of the die head group 21 and is connected to the rotating shaft 35 of the corresponding installed die swing assembly 3 through interference fit, so that the die assembly rotates axially around the rotating shaft 35. An adjustment and installation plate 23 is clamped between the middle positions of the male head 211 and the female head 212 for spacing adjustment;

[0019] Each group of the replacement part groups 22 includes an upper replacement part and a lower replacement part, which are correspondingly and fixedly installed on the front side end surfaces of the male head 211 and the female head 212;[[ID=​​​​Optionally, in the reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops as described above,

[0022] Each set of mold components 2 is used to adjust the gap between the male head 211 and the female head 212 by adjusting the mounting plate 23 to match the clamping plate of the stringer to be bent, and the clamping plate of the stringer is clamped by the upper replacement part and the lower replacement part, so as to be bent by the bending machine.

[0023] Among them, for the T-shaped stringer 71, the middle plate of its T-shaped part is used as a clamping plate, and its middle area is clamped between the upper replacement part and the lower replacement part of the mold assembly 2 located in the middle of the worktable 4.

[0024] For the L-shaped stringer 72, its short side plate is used as a clamping plate, and its central area is clamped between the upper and lower replacement parts of the mold assembly 2 located in the middle of the worktable 4.

[0025] Optionally, in the reconfigurable discrete die bending precision forming device for narrow tabletops as described above, each of the die swinging components 3 includes: a drag chain 31, a drag chain groove 32, a geared motor base 33, a geared motor 34, and a rotating shaft 35.

[0026] The cable chain groove 32 is installed radially above the integrated base 12 and the motor 11. The cable chain groove 32 is installed on the end face of the workbench 4 through a support frame. The geared motor 34 is installed on the top of the mounting base 15 at the corresponding position through the geared motor base 33. The rotating shaft 35 of the geared motor 34 passes through the geared motor base 33 and the mounting base 15 and is fixedly connected to the mold assembly 2 at the corresponding position. The rear end of the cable chain 31 is fixed in the cable chain groove 32, and the front end is fixed on the geared motor base 33. The geared motor 34 is arranged through the cable chain 31.

[0027] Optionally, in the reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops as described above,

[0028] The number of positioning grooves 42, longitudinal moving components 1, mold components 2, and mold swinging components 3 on the front bending working part of the workbench 4 is the same, and they are all set to an odd number; and the angle between adjacent positioning grooves 42 is not greater than 1.5°.

[0029] In a second aspect, embodiments of the present invention also provide a stretch bending machine for aircraft stringers, comprising: a stretch bending machine body, and a reconfigurable discrete mold stretch bending precision forming device for narrow platforms as described in any of the above.

[0030] The aircraft stringer to be bent has its two ends fixed on a bending machine. A reconfigurable discrete mold bending precision forming device is used to clamp the middle area of ​​the clamping end of the aircraft stringer for bending. During the bending process, the clamping end is gradually clamped from the middle to both sides.

[0031] Thirdly, embodiments of the present invention also provide a method for using a reconfigurable discrete mold stretch bending precision forming device for narrow platforms as described in any of the above claims to clamp an aircraft stringer and then perform a stretch bending operation on a stretch bending machine, comprising the following steps:

[0032] Step 1: Based on the type, hardness and radius of the stringer to be formed, select the matching replacement part 22 in the mold assembly 2 and install it onto the mold head assembly 21 of the mold assembly 2.

[0033] Step 2: After inputting the radius value of the stringer to be formed through the control system 5, the radial drive motor in each group of longitudinal moving components 1 drives each mounting base 15 to move to the position specified in the program, so that the longitudinal moving components 1 of the odd group are arranged symmetrically on both sides with the middle group as the center line.

[0034] Step 3: Control each set of mold swing components 3 through the control system 5 to drive the corresponding connected mold components 2 to rotate, so that the mold components 2 installed on the mounting base 15 of the longitudinal moving component 1 in the middle position remain stationary, and the mold components 2 on both sides rotate symmetrically to the program-specified angle. Under the motion control of the longitudinal moving component 1 and the mold swing component 3, the bending end faces of the replacement parts 22 in all mold components 2 are combined at multiple points to form the desired stringer theoretical shape.

[0035] Step 4: Fix the stringer on the bending machine. Through the control system, make the stringer gradually approach the mold assembly 2 of the forming device. First, use the mold assembly 2 in the middle position to clamp the middle area of ​​the stringer clamping plate. Then, clamp it symmetrically on both sides of the center line. As the stringer is bent, the stringer will gradually bend until it is completely in contact with the bending end face of the replacement part 22 at the front end of all mold assemblies 2.

[0036] Step 5: After completing the stringer bending and shaping, repeat steps 1 to 4 for the next stringer bending.

[0037] The beneficial effects of the present invention: The embodiments of the present invention provide a reconfigurable discrete mold stretch bending precision forming device and method for narrow tabletops, as well as a stretch bending machine. The main purpose is to solve the problems of the large number and high cost of traditional stretch bending forming molds, and to establish a reconfigurable discrete mold stretch bending precision forming device using existing stretch bending machines. The reconfigurable discrete mold stretch bending precision forming device provided in this invention allows for adjustable gaps and positions of the mold components, enabling the mold envelope formed at the end face to adapt to stretch bending forming of different curvatures and cross-sections. This method significantly reduces the number of stretch bending dies, shortens the manufacturing cycle of stretched bending parts, and lowers manufacturing costs. By utilizing the end density arrangement of mold components at preset angles and the arc approximation of the stretch bending end face of the replacement part 22 at the front end of the mold components, the requirement that the forming step difference of the profile surface is no greater than 0.05mm is achieved. The replaceable form of the replacement part 22 at the front end of the mold components enables springback compensation for different stretch bending profiles, ensuring high-quality stretch bending forming of aircraft stringer parts. By rotating each mold component at different angles using the mold swing component 3, a larger arc can be used to make surface contact with the profile, thereby achieving the stringer stretch bending requirements with a large curvature range on a narrow platform. The reconfigurable discrete mold stretch bending precision forming device provided in this invention can be extended to all aircraft stringer multi-point precision forming technology fields. Attached Figure Description

[0038] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0039] Figure 1 This is a schematic diagram of the overall structure of the reconfigurable discrete die stretch bending precision forming device for narrow tabletops provided in an embodiment of the present invention.

[0040] Figure 2 for Figure 1 A schematic diagram of the worktable in the reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops provided in the embodiment shown;

[0041] Figure 3 for Figure 1 The illustrated embodiment provides a schematic diagram of the worktable and a single set of longitudinal movement groups in a reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops.

[0042] Figure 4 for Figure 1 A schematic diagram of the mounting base in the reconfigurable discrete die stretch bending precision forming apparatus for narrow platforms provided in the embodiment shown;

[0043] Figure 5 for Figure 1Schematic structural diagram of the die assembly in the reconfigurable discrete die stretch bending precision forming device for a narrow tabletop provided by the illustrated embodiment;

[0044] Figure 6 For Figure 5 Schematic structural diagram of the die assembly for assembling a T-shaped longeron provided by the illustrated embodiment;

[0045] Figure 7 For Figure 5 Schematic structural diagram of the die assembly for assembling an L-shaped longeron provided by the illustrated embodiment;

[0046] Figure 8 [[ID=`16]]For Figure 1 Schematic structural diagram of the die swing assembly in the reconfigurable discrete die stretch bending precision forming device for a narrow tabletop provided by the illustrated embodiment.

[0047] Explanation of reference numerals:

[0048] 1 Longitudinal movement component; 11 Motor; 12 Integral seat; 13 Self-locking lead screw structure; 131 Nut; 14 Slide block and slide rail structure; 15 Mounting seat; 151 Intermediate vertical plate; 152 "C" - shaped structure; 153 Limit boss; 2 Die assembly; 21 Die head group; 211 Male head; 212 Female head; 22 Replacement end face; `23 Adjustment and installation plate; 3 Die swing assembly; 31 Drag chain; 32 Drag chain groove; 33 Reduction motor seat; `34 Reduction motor; 35 Rotating shaft; 4 Workbench; 41 Annular boss; 42 Positioning groove; 5 Control system; 6 Stretch bending machine; 71 T-shaped longeron; 72 L-shaped longeron. Detailed implementation manners

[0049] To make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, without conflict, the embodiments and features in the present application can be combined arbitrarily with each other.

[0050] As already described in the above background technology, longerons at various positions of the aircraft need to be stretch bent into different arcs by using stretch bending forming technology. The existing stretch bending methods have the following problems:

[0051] On the one hand, for the forming of each longeron, usually a set of traditional special stretch bending forming dies is required, and the number of stretch bending dies is huge, resulting in high die manufacturing costs;

[0052] [[ID=3`8]]On the other hand, during the production process, for the forming of each longeron, the disassembly and installation of the special die need to be carried out on the corresponding stretch bending machine tool. The multiple disassembly and installation positioning will cause wear to the positioner of the stretch bending machine tool. In the long term, it will lead to inaccurate positioning of the stretch bending machine tool, and further cause the longeron parts to be out of tolerance;

[0053] On the other hand, since the thickness of each set of special bending dies is different, the height of the bending die needs to be adjusted according to the position of the bending clamp during installation, which is inconvenient and results in low manufacturing efficiency.

[0054] Multi-point forming (MPF) is an improvement on traditional forming methods. Based on the idea of ​​discretization, the traditional integral mold is divided into a series of basic bodies with regular arrangement and adjustable positions. Each basic body can be independently controlled by a CNC adjustment system. The different compositions of each basic body will construct different profile bending forming surfaces.

[0055] For aircraft stringer parts, the forming quality requirements must meet two dimensions: shape accuracy and surface quality. The main influencing factors include the profile discretization method and the bending process parameters. One aircraft requires that the surface step indentation after bending of the stringer parts must not exceed 0.05mm, which places high demands on the discretization arrangement of the bending process and the fitting degree of the die head. Currently, the practical application of reconfigurable discrete die bending precision forming technology for aircraft stringer parts is limited, and it cannot meet the forming quality requirements of aircraft parts.

[0056] Considering the utilization of existing stretch bending machines, this invention develops a flexible stretch bending die by studying a method for flexible stretch bending forming of discrete stretch bending dies composed of basic elements on existing stretch bending machines. Specifically, this invention provides a reconfigurable discrete die stretch bending precision forming device and method for use on narrow table surfaces. This device enables precise stretch bending forming of discrete dies with an adjustable curvature range on the limited width of the stretch bending machine table, reducing the number of tooling fixtures and solving problems related to both die structure design and part forming quality control.

[0057] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0058] Figure 1 This is a schematic diagram of the overall structure of the reconfigurable discrete die stretch bending precision forming device for narrow tabletops provided in an embodiment of the present invention. Figure 2 for Figure 1 The illustrated embodiment provides a schematic diagram of the worktable structure in a reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops. See also... Figure 1 and Figure 2 The reconfigurable discrete die bending precision forming device for narrow tabletops provided in this embodiment of the invention includes: a longitudinal moving component 1, a die component 2, a die swinging component 3, a worktable 4, and a control system 5.

[0059] like Figure 1 and Figure 2As shown, in this embodiment of the invention, the workbench 4 is fixedly installed on the narrow table surface of the bending machine 6. The workbench 4 is configured as a stepped fan ring structure, including a front bending working part located on the side away from the center and a rear mounting part located on the side close to the center. The upper surface of the front bending working part is evenly arranged with a plurality of positioning grooves 42 in the radial direction along the circumference.

[0060] Figure 3 for Figure 1 The illustrated embodiment provides a schematic diagram of the worktable and a single set of longitudinal movement groups in a reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops. See also... Figure 1 , Figure 2 , Figure 3 In this embodiment of the invention, the mounting base 15 of the front end of the longitudinal moving component 1 is installed in each positioning groove 42 of the workbench 4, and the driving mechanism of each longitudinal moving component 1 is installed through the rear mounting part. Each mounting base 15 is equipped with a mold component 2, and the top of the mounting base 15 is equipped with a mold swing component 3. The rotating shaft of the mold swing component 3 passes through the mounting base 15 and is fixedly connected to the mold component 2.

[0061] See Figure 1 As shown, a single mold assembly 2 is used to move radially to a designated position under the push of its mounted longitudinal moving assembly 1, and deflects by a corresponding angle and maintains the deflection angle under the drive of the connecting shaft of the mold swing assembly 3.

[0062] In the embodiments of the present invention, under the attitude adjustment of each set of longitudinal moving components 1 and mold swing components 3 on the workbench 4, the end face of each mold component 2 forms a stringer theoretical shape with different radii through multi-point fitting, and keeps the position of each mold component 2 locked during the bending process of the bending machine 6, and simultaneously completes the bending process of multiple stringers of the aircraft.

[0063] In this embodiment of the invention, the control system 5 is connected to the drive mechanism in each mold swing assembly 3 and each longitudinal movement assembly 1, respectively. It is used to control each set of longitudinal movement assemblies 1 to move radially to form the overall bending trend of the stringer to be bent, and to control each mold swing assembly 3 to rotate so as to drive the rotation of each mold assembly 2, so that the bending end face of each mold assembly 2 matches the bending profile of each section of the stringer at the corresponding position.

[0064] In one implementation of this invention, see [link to relevant documentation]. Figure 2 As shown, the rear end mounting part of the workbench 4 has a fan-shaped annular boss 41, and the side of the fan-shaped annular boss 41 near the front end bending working part is provided with a fan-shaped mounting step that is lower than the fan-shaped annular boss 41.

[0065] See Figure 2 , Figure 3, each set of longitudinal moving components 1 in this implementation method includes: a motor 11, an integral seat 12, a self-locking screw structure 13, a slider rail structure 14, and a mounting seat 15.

[0066] In this implementation method, the slider rail structure 14 is fixedly installed in the positioning groove 42 at the corresponding position in the workbench 4; the bottom of the mounting seat 15 is a flat plate structure and is fixedly connected to the slider sliding on the rail in the slider rail structure 14; the bottom surface of the integral seat 12 is fixed on the fan-shaped mounting step at the front end of the boss 41 of the workbench 4, and its rear end surface is closely in contact with the front side end surface of the boss 41, for resisting the pressure exerted during the forming of the aircraft stringer. The motor 11 is installed on the rear end surface of the integral seat 12, and the rear end of the self-locking screw structure 13 passes through the integral seat 12 and is connected to the driving shaft of the motor 11. The front end of the self-locking screw structure 13 is fixedly connected to the mounting seat 15 through a nut 131, and drives the mounting seat 15 to move radially along the positioning groove 42 under the drive of the motor 11. In one implementation method of the embodiment of the present invention, an implementation scheme of the mounting seat 15 is provided. Figure 4 For Figure 1 the structural schematic diagram of the mounting seat in the reconfigurable discrete die stretch bending precise forming device for a narrow tabletop provided in the shown embodiment. Refer to Figure 3 , Figure 4 As shown, the mounting seat 15 includes: a fixed bottom plate, an intermediate vertical plate 151, and a top mounting portion.

[0067] In this implementation method, the mounting seat 15 is installed on the slider of the corresponding rail through the fixed bottom plate. The intermediate vertical plate 151 is vertically arranged in the middle of the fixed bottom plate. A through hole is provided on the intermediate vertical plate 151 for the front end of the self-locking screw structure 13 to pass through the through hole and be fixed by a nut 131. The top mounting portion is set as a "C" - shaped structure 152 for semi - embeddedly sleeving and installing the die assembly 2 through the "C" - shaped structure 152. A limiting boss 153 for installing the die assembly 2 is provided on the upper surface of the lower end of the "C" - shaped structure 152. Coaxial holes are provided in the vertical direction on the upper and lower plates of the "C" - shaped structure 152 for installing the rotating shaft 35 of the die swing component 3.

[0068] In one implementation method of the embodiment of the present invention, an implementation scheme of the die assembly 2 is provided. Refer to Figure 5 , Figure 6 , Figure 7 , each die assembly 2 includes: a die head group 21, multiple sets of replacement part groups 22, and an adjustment and installation plate 23. Figure 5 For Figure 1 the structural schematic diagram of the die assembly in the reconfigurable discrete die stretch bending precise forming device for a narrow tabletop provided in the shown embodiment; Figure 6 For Figure 5 the structural schematic diagram of the die assembly for assembling a T - shaped stringer provided in the shown embodiment; Figure 7for Figure 5 The illustrated embodiment provides a schematic diagram of the assembly of an L-shaped stringer with a mold component.

[0069] In this implementation, the mold head assembly 21 includes a male head 211 and a female head 212 that are installed in a relative manner. The rear end of the mold head assembly 21 has a through hole, which is connected to the rotating shaft 35 of the corresponding mold swing assembly 3 by an interference fit, so that the mold assembly can rotate around the rotating shaft 35. An adjustment plate 23 is clamped in the middle of the male head 211 and the female head 212 for spacing adjustment.

[0070] Each replacement part group 22 includes an upper replacement part and a lower replacement part, which are fixedly installed on the front end faces of the male connector 211 and the female connector 212, respectively. In addition, the front end faces of each replacement part group 22 are set as arc ends with different curvatures to accommodate stringers of different materials and bending radii.

[0071] based on Figure 5 The mold assembly 2 structure provided in the embodiment shown is used in the following way: the gap between the male head 211 and the female head 212 is adjusted by the adjustment plate 23 to match the clamping plate of the stringer to be bent, and the clamping plate of the stringer is clamped by the upper replacement part and the lower replacement part, so as to be bent by the bending machine.

[0072] In this implementation, one application of the mold assembly 2 is as follows: For the T-shaped stringer 71, the middle plate of its T-shaped section is used as a clamping plate, and its central area is clamped between the upper and lower replacement parts of the mold assembly 2 located in the middle of the worktable 4. For example... Figure 6 The T-shaped stringer 71 shown is assembled on the mold assembly 2.

[0073] Another application of the mold assembly 2 in this implementation is as follows: For the L-shaped stringer 72, its short side plate is used as a clamping plate, and its central region is clamped between the upper and lower replacement parts of the mold assembly 2 located in the middle of the worktable 4. For example... Figure 7 The L-shaped stringer 72 shown is assembled on mold assembly 2.

[0074] In one implementation of the present invention, a mold oscillation assembly 3 is provided. Figure 8 for Figure 1 The illustrated embodiment provides a schematic diagram of the die oscillation assembly in a reconfigurable discrete die stretch bending precision forming apparatus for narrow platforms. See also... Figure 3 , Figure 8 Each mold swing assembly 3 in this implementation includes: a drag chain 31, a drag chain groove 32, a geared motor base 33, a geared motor 34, and a rotating shaft 35.

[0075] In this implementation, the cable chain groove 32 is installed radially above the integrated base 12 and the motor 11. The cable chain groove 32 is installed on the end face of the workbench 4 via a support frame. The geared motor 34 is installed on the top of the mounting base 15 at the corresponding position via a geared motor base 33. The rotating shaft 35 of the geared motor 34 passes through the geared motor base 33 and the mounting base 15 and is fixedly connected to the mold assembly 2 at the corresponding position. The rear end of the cable chain 31 is fixed in the cable chain groove 32, and the front end is fixed on the geared motor base 34. The geared motor 34 is arranged through the cable chain 31.

[0076] In the above embodiments of the present invention, the reconfigurable discrete mold bending precision forming device for narrow tabletops has the same number of positioning grooves 42, longitudinal moving components 1, mold components 2, and mold swinging components 3 on the front bending working part of the worktable 4, all of which are set to an odd number; and the angle between adjacent positioning grooves 42 is not greater than 1.5°.

[0077] Based on the reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops provided in the above embodiments of the present invention, see [link to previous document]. Figure 1 The present invention also provides a stretch bending machine for aircraft stringers, comprising: a stretch bending machine 6 body, and a reconfigurable discrete mold stretch bending precision forming apparatus for narrow platforms as provided in any of the above embodiments.

[0078] The aircraft stringer to be bent has its two ends fixed on the bending machine 6. The middle area of ​​the clamping end of the aircraft stringer is clamped by a reconfigurable discrete mold bending precision forming device for bending. During the bending process, the clamping end is gradually clamped from the middle to both sides.

[0079] Based on the reconfigurable discrete die bending precision forming apparatus for narrow platforms provided in the above embodiments of the present invention, the present invention also provides a method of using the reconfigurable discrete die bending precision forming apparatus for narrow platforms. Specifically, the method involves clamping an aircraft stringer with the reconfigurable discrete die bending precision forming apparatus for narrow platforms provided in any of the above embodiments and then performing a bending operation on a bending machine, including the following steps:

[0080] Step 1: Based on the type, hardness and radius of the stringer to be formed, select the matching replacement part 22 in the mold assembly 2 and install it onto the mold head assembly 21 of the mold assembly 2.

[0081] Step 2: After inputting the radius value of the stringer to be formed through the control system 5, the radial drive motor in each group of longitudinal moving components 1 drives each mounting base 15 to move to the position specified in the program, so that the longitudinal moving components 1 of the odd group are arranged symmetrically on both sides with the middle group as the center line.

[0082] Step 3: Control each set of mold swing components 3 through the control system 5 to drive the corresponding connected mold components 2 to rotate, so that the mold components 2 installed on the mounting base 15 of the longitudinal moving component 1 in the middle position remain stationary, and the mold components 2 on both sides rotate symmetrically to the program-specified angle. Under the motion control of the longitudinal moving component 1 and the mold swing component 3, the bending end faces of the replacement parts 22 in all mold components 2 are combined at multiple points to form the desired stringer theoretical shape.

[0083] Step 4: Fix the stringer on the bending machine. Through the control system, make the stringer gradually approach the mold assembly 2 of the forming device. First, use the mold assembly 2 in the middle position to clamp the middle area of ​​the stringer clamping plate. Then, clamp it symmetrically on both sides of the center line. As the stringer is bent, the stringer will gradually bend until it is completely in contact with the bending end face of the replacement part 22 at the front end of all mold assemblies 2.

[0084] Step 5: After completing the stringer bending and shaping, repeat steps 1 to 4 for the next stringer bending.

[0085] This invention utilizes the narrow platform of an existing stretch bending machine to establish a reconfigurable discrete die stretch bending precision forming device. By adjusting the gap and orientation of the die components, the die envelope formed at the end face can adapt to stretch bending forming of different curvatures and cross-sections. This method can significantly reduce the number of stretch bending dies, shorten the manufacturing cycle of stretched bending parts, and lower manufacturing costs. Using die heads evenly distributed at 1.5°, the density arrangement requirements for profile stretch bending are met. Replaceable end faces of the die heads enable springback compensation of the stretched profile, ensuring high-quality stretch bending forming of aircraft stringer parts. This invention can be directly applied to the field of multi-point precision forming technology for all aircraft stringers.

[0086] This invention provides a reconfigurable discrete mold stretch bending precision forming device and its usage method for narrow tabletops. The main purpose is to solve the problems of the large number and high cost of traditional stretch bending forming dies, and to establish a reconfigurable discrete mold stretch bending precision forming device using existing stretch bending machines. The reconfigurable discrete mold stretch bending precision forming device provided in this invention allows for adjustable gaps and positions of the mold components, enabling the mold envelope formed at the end face to adapt to stretch bending forming of different curvatures and cross-sections. This method significantly reduces the number of stretch bending dies, shortens the manufacturing cycle of stretched bending parts, and lowers manufacturing costs. By utilizing the end density arrangement of mold components at preset angles and the arc approximation of the stretch bending end face of the replacement part 22 at the front end of the mold components, the requirement that the forming step difference of the profile surface is no greater than 0.05mm is achieved. The replaceable form of the replacement part 22 at the front end of the mold components enables springback compensation for different stretch bending profiles, ensuring high-quality stretch bending forming of aircraft stringer parts. By rotating each mold component at different angles using the mold swing component 3, a larger arc can be used to make surface contact with the profile, thereby achieving the stringer stretch bending requirements with a large curvature range on a narrow platform. The reconfigurable discrete mold stretch bending precision forming device provided in this invention can be extended to all aircraft stringer multi-point precision forming technology fields.

[0087] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A reconfigurable discrete die stretch bending precision forming apparatus for narrow platform surfaces, characterized in that, include: The longitudinal movement assembly (1), the mold assembly (2), the mold swing assembly (3), the worktable (4), and the control system (5); The workbench (4) is fixedly installed on the narrow table surface of the bending machine (6). The workbench (4) is configured as a stepped fan ring structure, including a front bending working part located away from the center and a rear mounting part located near the center. The upper surface of the front bending working part is evenly arranged with multiple positioning grooves (42) in the radial direction along the circumference, and the angle between adjacent positioning grooves (42) is not greater than 1.5°. The mounting base (15) of the front end of the longitudinal moving component (1) is installed in each positioning groove (42) of the worktable (4), and the drive mechanism of each longitudinal moving component (1) is installed through the rear mounting part. Each mounting base (15) is equipped with a mold component (2), and the top of the mounting base (15) is equipped with a mold swing component (3). The rotating shaft of the mold swing component (3) passes through the mounting base (15) and is fixedly connected to the mold component (2). A single mold assembly (2) is moved radially to a designated position by the push of its mounted longitudinal moving assembly (1), and deflects by a corresponding angle and maintains the deflection angle by the drive of the connecting shaft of the mold swing assembly (3); Under the adjustment of the longitudinal moving components (1) and the mold swinging components (3) on the workbench (4), the end faces of each mold component (2) form the theoretical shape of the stringer with different radii through multi-point fitting, and keep the position of each mold component (2) locked during the bending process of the bending machine (6), and simultaneously complete the bending process of multiple stringers of the aircraft. The control system (5) is connected to the drive mechanism in each mold swing assembly (3) and each longitudinal movement assembly (1) respectively. It is used to control each group of longitudinal movement assemblies (1) to move radially through the control system (5) to form the overall bending trend of the stringer to be bent, and to control each mold swing assembly (3) to rotate so as to drive the rotation of each mold assembly (2) so that the bending end face of each mold assembly (2) matches the bending profile of each section of the stringer at the corresponding position. Each of the mold components (2) includes: a mold head assembly (21), multiple sets of replacement parts (22), and an assembly plate (23); The mold head assembly (21) includes a male head (211) and a female head (212) that are installed in opposite directions. The rear end of the mold head assembly (21) has a through hole, which is connected to the rotating shaft (35) of the corresponding mold swing assembly (3) by an interference fit, so that the mold assembly can rotate around the rotating shaft (35) axially. An adjustment plate (23) is clamped in the middle of the male head (211) and the female head (212) for spacing adjustment. Each replacement part group (22) includes an upper replacement part and a lower replacement part, which are fixedly installed on the front end faces of the male head (211) and the female head (212); The front end face of each replacement part (22) is set as an arc end with different curvatures to fit the stringers with different materials and bending radii.

2. The reconfigurable discrete die stretch bending precise forming device for a narrow tabletop according to claim 1, wherein a fan-shaped ring boss (41) is provided on the rear mounting part of the workbench (4), and a fan-shaped mounting step lower than the fan-shaped ring boss (41) is provided on one side of the fan-shaped ring boss (41) close to the front stretch bending working part; each set of the longitudinal movement components (1) includes: a motor (11), an integral seat (12), a self-locking lead screw structure (13), a slider rail structure (14), and a mounting seat (15); wherein, the slider rail structure (14) is fixedly installed in a positioning groove (42) at a corresponding position in the workbench (4); the bottom of the mounting seat (15) is a flat plate structure and is fixedly connected to a slider sliding on the rail in the slider rail structure (14); the bottom surface of the integral seat (12) is fixed on the fan-shaped mounting step at the front end of the boss (41) of the workbench (4), and its rear end surface is closely contacted with the front side end surface of the boss (41) for resisting the pressure exerted during the forming of the aircraft longeron. The motor (11) is installed on the rear end surface of the integral seat (12), the rear end of the self-locking lead screw structure (13) passes through the integral seat (12) and is connected to the driving shaft of the motor (11), and the front end of the self-locking lead screw structure (13) is fixedly connected to the mounting seat (15) through a nut (131), and drives the mounting seat (15) to move radially on the positioning groove (42) under the drive of the motor (11).

3. The reconfigurable discrete die stretch bending precision forming device for narrow tabletops as described in claim 2, characterized in that, the mounting seat (15) includes: a fixed bottom plate, an intermediate vertical plate (151), and a top mounting part; wherein, the mounting seat (15) is installed on the slider of the corresponding rail through the fixed bottom plate, the intermediate vertical plate (151) is vertically arranged in the middle of the fixed bottom plate, a through hole is provided on the intermediate vertical plate (151) for the front end of the self-locking lead screw structure (13) to pass through the through hole and be fixed by a nut (131), the top mounting part is set as a "C" - shaped structure (152) for semi-embeddedly sleeving and installing the die assembly (2) through the "C" - shaped structure (152). A limiting boss (153) for installing the die assembly (2) is provided on the upper surface of the lower end of the "C" - shaped structure (152), and coaxial holes are provided in the upper and lower plates of the "C" - shaped structure (152) in the vertical direction for installing the rotating shaft (35) of the die swing assembly (3).

4. The reconfigurable discrete die stretch bending precise forming device for a narrow tabletop according to claim 1, wherein each set of the die assemblies (2) is used to adjust the gap between the male head (211) and the female head (212) through an adjustment plate (23) to cooperate with the clamping plate of the to-be-stretch-bent longeron, and clamp the clamping plate of the longeron through the upper replacement part and the lower replacement part, so as to perform stretch bending through a stretch bending machine; wherein, for a T-shaped longeron (71), the middle plate of its T-shaped part is used as the clamping plate, and the middle area thereof is clamped between the upper replacement part and the lower replacement part of the die assembly (2) located in the middle of the workbench (4). For the L-shaped stringer (72), its short side plate is used as a clamping plate, and its middle area is clamped between the upper and lower replacement parts of the mold assembly (2) located in the middle of the worktable (4).

5. The reconfigurable discrete die stretch bending precision forming device for narrow tabletops as described in claim 2, characterized in that, Each of the mold swing assembly (3) includes: a cable chain (31), a cable chain groove (32), a geared motor base (33), a geared motor (34), and a rotating shaft (35); The drag chain groove (32) is installed radially above the integrated base (12) and the motor (11). The drag chain groove (32) is installed on the end face of the workbench (4) through the support frame. The geared motor (34) is installed on the top of the mounting seat (15) at the corresponding position through the geared motor seat (33). The shaft (35) of the geared motor (34) passes through the geared motor seat (33) and the mounting seat (15) and is fixedly connected to the mold assembly (2) at the corresponding position. The rear end of the drag chain (31) is fixed in the drag chain groove (32), and the front end is fixed on the geared motor seat (33). The geared motor (34) is arranged through the drag chain (31).

6. A reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops as described in any one of claims 1 to 5, characterized in that, The number of positioning grooves (42), longitudinal moving components (1), mold components (2), and mold swinging components (3) provided on the front bending working part of the worktable (4) is the same, and they are all set to an odd number.

7. A tension bending machine for aircraft stringers, characterized in that, include: The body of the stretch bending machine, and the reconfigurable discrete mold stretch bending precision forming device for narrow tabletops as described in any one of claims 1 to 6; The aircraft stringer to be bent has its two ends fixed on a bending machine. A reconfigurable discrete mold bending precision forming device is used to clamp the middle area of ​​the clamping end of the aircraft stringer for bending. During the bending process, the clamping end is gradually clamped from the middle to both sides.

8. A method of using a reconfigurable discrete die stretch bending precision forming apparatus for narrow tabletops, characterized in that... The method of using the reconfigurable discrete mold stretch bending precision forming device for narrow tabletops, as described in any one of claims 1 to 6, to clamp an aircraft stringer and then perform a stretch bending operation on a stretch bending machine includes the following steps: Step 1: Select the matching replacement part (22) in the mold assembly (2) according to the type, hardness and radius of the stringer to be formed, and install it on the mold head assembly (21) of the mold assembly (2); Step 2: After inputting the radius value of the long string to be formed through the control system (5), the radial drive motor in each group of longitudinal moving components (1) drives each mounting seat (15) to move to the position specified in the program, so that the longitudinal moving components (1) of the odd group are arranged symmetrically on both sides with the middle group as the center line. Step 3: Control each set of mold swing components (3) through the control system (5) to drive the corresponding connected mold components (2) to rotate, so that the mold components (2) installed on the mounting seat (15) of the longitudinal moving component (1) in the middle position remain stationary, and the mold components (2) on both sides rotate symmetrically to the angle specified by the program. Under the motion control of the longitudinal moving component (1) and the mold swing component (3), the bending end faces of the replacement parts (22) in all mold components (2) are combined at multiple points to form the desired stringer theoretical shape. Step 4: Fix the stringer on the bending machine and use the control system to make the stringer gradually approach the mold assembly (2) of the forming device. First, use the mold assembly (2) in the middle position to clamp the middle area of ​​the stringer clamping plate, and then clamp it symmetrically on both sides of the center line. As the stringer is bent, the stringer will gradually bend until it is completely in contact with the bending end face of the replacement part (22) at the front end of all mold assemblies (2). Step 5: After completing the stringer bending and shaping, repeat steps 1 to 4 for the next stringer bending.

Images