A method for controlling the shape of a large-opening thin-wall weak-rigidity window frame part

Abstract

The application discloses a shape control method for a large-opening thin-wall weak-rigidity window frame part, which comprises a positioning base, a shape-keeping clamp block, a rigid window frame part, a flexible supporting block, a process boss, a locking screw limiter, a side stop limiting bolt and a flexible clamping assembly. The shape control method is realized through cooperation of the flexible clamping assembly and the shape-keeping clamp block. Deformation control is performed on the part in the semi-finishing and finishing stages in X, Y and Z directions, the deformation amount under the weight of the workpiece and the strain amount in the semi-finishing process can be compensated, thereby realizing flexible, efficient, reliable and rapid positioning and clamping, and the machining deformation amount caused by the weight of the workpiece and internal stress can be greatly reduced and compensated. Through the heat treatment shape control process, the deformation caused by uneven distribution of thermal stress and organizational stress is reduced, and secondary deflection deformation of the part caused by excessive weight during the heat preservation and cooling process is avoided due to the increase of plasticity of the part during the heat treatment.

Description

Technical Field

[0001] This invention relates to the field of shape control technology in parts manufacturing, specifically a shape control method for a large-opening, thin-walled, weakly rigid window frame part. Background Technology

[0002] As an important structural component of the nose, the windshield frame is designed to be integrated and thin-walled in order to meet the requirements of long service life, lightweight and easy maintenance of aircraft. Currently, such parts have the characteristics of spatial hyperbola, large opening, large bow height, weak overall rigidity, complex and variable cross-section, and high requirements for precision and coordination. Moreover, as material is removed, the shape of the part changes nonlinearly during the processing under the action of internal stress balance.

[0003] In traditional processing methods, the shape of parts changes significantly due to changes in internal stress and their own weight after heat treatment. During processing, shape control methods such as natural aging and multi-station datum repair are used to gradually eliminate deformation in a free state. However, the processing cycle is long and the shape control effect is generally poor.

[0004] The thin-walled part shape control technology adopts heat treatment shape control technology, large-thickness forging stress division technology, and low-stress support shape-preserving tooling processing. It releases and corrects the deformation caused by thermal stress and internal stress in advance for different stages of the part manufacturing process, reduces the roughing cycle, and effectively controls the deformation of the part. Traditional shape control methods have the disadvantages of incomplete stress release, long processing cycle, and difficulty in guaranteeing theoretical shape dimensions. They cannot effectively control the high-precision theoretical shape deformation of large-opening thin-walled weak rigidity window frame parts. Summary of the Invention

[0005] The purpose of this patent is to disclose a shape control method for large-opening, thin-walled, weakly rigid window frame parts. This method can overcome the shortcomings of traditional shape control methods, such as incomplete stress release, long processing cycle, and difficulty in guaranteeing theoretical external dimensions, and achieve effective control of high-precision theoretical external shape deformation of large-opening, thin-walled, weakly rigid window frame parts.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component includes a positioning base, a conformal clamping block, a rigid window frame component, a flexible support block, a process boss, a locking screw limiter, a side-stop limit bolt, and a flexible clamping assembly for positioning and adjusting the rigid window frame component. The conformal clamping block and the flexible clamping assembly fix the rigid window frame component to the base surface of the positioning base. The specific steps are as follows:

[0008] Step 1: Before heat treatment, the rigid window frame parts are placed in a steel frame. The upper part of the rigid window frame parts is supported by steel rods and pulled by multiple strands of steel wire ropes with zero force. The multiple strands of steel wire ropes are evenly distributed on the outer wall of the rigid window frame parts, so that the self-weight and stress of the rigid window frame parts are dispersed in multiple directions after softening at high temperature, reducing the impact of heat treatment on the shape changes of the rigid window frame parts.

[0009] Step 2: Remove the middle and surrounding areas where the internal stress of the raw material is concentrated, thereby changing the direction of the internal stress in the thick free forging.

[0010] Step 3: Adjust the flexible support block in the normal direction between each station while the rigid window frame parts are in a free state, so that the process boss is in close contact with the upper surface of the support body, and at the same time tighten the screw limiter and the side stop limit bolt to compensate for the self-weight of the rigid window frame parts.

[0011] During finishing, conformal clamps are used to fix and tighten the rigid window frame parts, providing sufficient axial locking force so that the rigid window frame parts are machined in a conformal state.

[0012] As a preferred embodiment of the present invention, the flexible clamping assembly includes a mounting base, an mounting hole on the outer wall of the mounting base, a connecting bolt on the inner wall of the mounting hole, a flexible support block at the port of the mounting base, a fixing bolt on the inner wall of the flexible support block, an mounting groove on one side of the fixing bolt and on the inner wall of the flexible support block, a limit spring on the inner wall of the mounting groove, a protrusion on one end of the fixing bolt, a helical limiter threaded on the outer wall of the flexible support block, a sliding groove on the side wall of the mounting base, a side stop limit bolt slidably connected to the inner wall of the sliding groove, a positioning groove on the outer wall of the mounting base, a protruding plate on the outer wall of the mounting base, a fixing hole on the outer wall of the protruding plate, a fixing bolt inserted into the inner wall of the fixing hole, and a process boss on the outer wall of the fixing bolt.

[0013] As a preferred embodiment of the present invention, the mounting base has an L-shaped cross-section, multiple sets of mounting holes are provided and are respectively mounted on the outer wall of the base, multiple sets of connecting bolts are provided and are respectively located on the inner wall of the mounting holes, the connecting bolts are located on one side of the protrusion, and the flexible support block has a T-shaped cross-section.

[0014] As a preferred embodiment of the present invention, the fixing bolts are provided in two sets and are respectively located on the inner walls of the flexible support block and the fixing hole, the mounting groove is located in the inner cavity of the mounting base, and the limiting spring is located in the inner cavity of the mounting base.

[0015] As a preferred embodiment of the present invention, the limiting spring is located on one side of the protrusion, the spiral limiter is located directly above the mounting base, and one end of the side stop limiting bolt passes through the slide groove and extends to one side of the slide groove to be connected to a flexible support block.

[0016] As a preferred embodiment of the present invention, the sliding groove is located directly above the mounting hole, the sliding groove is located on one side of the convex plate, the positioning groove is located on one side of the flexible support block, and the convex plate is located at the port of the mounting base.

[0017] As a preferred embodiment of the present invention, the convex plate is located on one side of the flexible support block, the fixing hole is located on one side of the flexible support block, and the cross-section of the conformal clamping block is an L-shaped structure.

[0018] As a preferred embodiment of the present invention, the outer wall of the process boss is provided with a connecting hole, and two sets of the connecting holes are respectively located on the outer wall of the process boss. A fixing bolt is connected to the inner wall of the connecting hole, and the process boss is located directly above the flexible support block.

[0019] Compared with the prior art, the present invention uses a form control method that combines flexible clamping components and conformal clamping blocks in the form control method of large-opening thin-walled weak rigid window frame parts. This method controls the deformation of the parts in the X, Y, and Z directions during the semi-finishing and finishing stages, which can compensate for the deformation under the workpiece's own weight and the strain during the semi-finishing process. This achieves flexible, efficient, reliable, and rapid positioning and clamping, and can significantly reduce and compensate for the processing deformation caused by the workpiece's own weight and internal stress. The heat treatment form control process reduces the deformation caused by uneven distribution of thermal stress and structural stress, and avoids secondary bending deformation caused by the increased plasticity of the parts during heat treatment and excessive self-weight of the parts during the heat preservation and cooling processes.

[0020] By employing free forging unloading and optimal part layout techniques, free forging with concentrated and unevenly distributed internal stress is milled into a process similar to die forging. On the one hand, this completely releases a large amount of internal stress in the center and surrounding areas of the material. On the other hand, the optimization of the part's orientation ensures a more uniform stress distribution after rough machining. This effectively avoids irregular deformation of parts caused by uneven stress distribution after traditional rough machining, reducing the difficulty of shape control during semi-finishing and finishing processes. This solves the shortcomings of traditional shape control methods, such as incomplete stress release, long processing cycles, and difficulty in guaranteeing theoretical external dimensions. It also addresses the problem of not being able to effectively control the high-precision theoretical external shape deformation of large-opening, thin-walled, and weakly rigid window frame parts. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the process boss structure of the present invention;

[0023] Figure 3 This is a schematic diagram of the flexible clamping component structure of the present invention;

[0024] Figure 4 This is a cross-sectional structural diagram of the mounting base of the present invention;

[0025] Figure 5 This is a side view of the structure of the present invention;

[0026] Figure 6 This is a schematic diagram of the heat treatment shape control technology of the present invention;

[0027] Figure 7 This is a schematic diagram of stress division in the thick forging of the present invention.

[0028] In the diagram: 1. Positioning base; 2. Conformal clamping block; 3. Flexible clamping assembly; 301. Mounting base; 302. Mounting hole; 303. Connecting bolt; 304. Fixing bolt; 305. Mounting groove; 306. Limiting spring; 307. Protrusion; 308. Slide groove; 309. Positioning groove; 310. Protruding plate; 311. Fixing hole; 4. Rigid window frame parts; 5. Flexible support block; 6. Process boss; 7. Spiral limiter; 8. Side stop limiting bolt. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Example: Please refer to Figure 1-7 The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component, as shown, includes a positioning base 1, a conformal clamping block 2, a rigid window frame component 4, a flexible support block 5, a process boss 6, a locking screw limiter 7, a side stop limit bolt 8, and a flexible clamping assembly 3 for positioning and adjusting the rigid window frame component 4. The conformal clamping block 2 and the flexible clamping assembly 3 fix the rigid window frame component 4 to the base surface of the positioning base 1. The specific steps are as follows:

[0031] Step 1: Before heat treatment, according to... Figure 6 The rigid window frame part 4 is placed in a steel frame. The upper part of the rigid window frame part 4 is supported by a steel rod and pulled by multiple steel wire ropes with zero force. The multiple steel wire ropes are evenly distributed on the outer wall of the rigid window frame part 4, so that the self-weight and stress of the rigid window frame part 4 are dispersed in multiple directions after softening at high temperature, reducing the impact of heat treatment on the shape change of the rigid window frame part 4.

[0032] Step 2, press Figure 7 The method shown removes the middle and surrounding areas where the internal stress of the raw material is concentrated, changes the direction of the internal stress in the thick free forging, and greatly reduces the weight, thereby reducing the deformation of the part caused by the material frame during rough machining.

[0033] Step 3, press Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the flexible support block 5 is adjusted normally between each workstation in the free state of the rigid window frame part 4, so that the process boss 6 is in close contact with the upper surface of the support body. At the same time, the locking screw limiter 7 and the side stop limit bolt 8 compensate for the self-weight of the rigid window frame part 4. During the finishing process, the conformal clamping block 2 is used to fix and tighten the rigid window frame part 4, providing sufficient axial locking force so that the rigid window frame part 4 is processed in the conformal state. The coordination of the two effectively ensures the accuracy of the position and posture of the rigid window frame part 4 during the finishing process, and avoids the vibration of the rigid window frame part 4 with large opening and thin wall due to poor rigidity.

[0034] In this embodiment, specific references Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The flexible clamping assembly 3 includes a mounting base 301. A mounting hole 302 is formed on the outer wall of the mounting base 301. A connecting bolt 303 is installed on the inner wall of the mounting hole 302. A flexible support block 5 is installed at the port of the mounting base 301. A fixing bolt 304 is installed on the inner wall of the flexible support block 5. A mounting groove 305 is formed on one side of the fixing bolt 304 and on the inner wall of the flexible support block 5. A limit spring 306 is installed on the inner wall of the mounting groove 305. A protrusion is installed at one end of the fixing bolt 304. 307. A spiral limiter 7 is threaded on the outer wall of the flexible support block 5. A sliding groove 308 is provided on the side wall of the mounting base 301. A side stop limit bolt 8 is slidably connected on the inner wall of the sliding groove 308. A positioning groove 309 is provided on the outer wall of the mounting base 301. A protruding plate 310 is installed on the outer wall of the mounting base 301. A fixing hole 311 is provided on the outer wall of the protruding plate 310. A fixing bolt 304 is inserted and pulled on the inner wall of the fixing hole 311. A process boss 6 is installed on the outer wall of the fixing bolt 304.

[0035] In this embodiment, specific references Figure 2 and Figure 3The mounting base 301 has an L-shaped cross-section. Multiple sets of mounting holes 302 are provided on the outer wall of the mounting base 301. Multiple sets of connecting bolts 303 are provided on the inner wall of the mounting holes 302. The connecting bolts 303 are located on one side of the protrusion 307. The flexible support block 5 has a T-shaped cross-section. Two sets of fixing bolts 304 are provided, located on the inner walls of the flexible support block 5 and the fixing hole 311, respectively. The mounting groove 305 is located in the inner cavity of the mounting base 301. The limiting spring 306 is located in the inner cavity of the mounting base 301, on one side of the protrusion 307. The spiral limiter 7 is located directly above the mounting base 301. The side stop limiting bolt 8... A flexible support block 5 is connected to one side of a slide groove 308. The slide groove 308 is located directly above the mounting hole 302 and is located on one side of the protrusion 310. The positioning groove 309 is located on one side of the flexible support block 5. The protrusion 310 is located at the port of the mounting base 301 and is located on one side of the flexible support block 5. The fixing hole 311 is located on one side of the flexible support block 5. The conformal clamp 2 has an L-shaped cross-section. A connecting hole is provided on the outer wall of the process boss 6. Two sets of connecting holes are provided and are located on the outer wall of the process boss 6. A fixing bolt 304 is connected to the inner wall of the connecting hole. The process boss 6 is located directly above the flexible support block 5.

[0036] Among them, due to factors such as the poor structural rigidity of rigid window frame part 4, its excessive self-weight after rough machining (nearly 1500Kg), improper support or clamping of rigid window frame part 4 during heating and cooling in the furnace, uneven temperature distribution, or phase transformation, rigid window frame part 4 generates large internal stress and residual stress, resulting in significant deformation after heat treatment. To address the deformation after heat treatment, after rough machining, a 20mm allowance is uniformly left for rigid window frame part 4, and equidistant and equal-height process bosses 6 are set on both the inner and outer sides of rigid window frame part 4 to avoid stress concentration. Multiple suspension points are uniformly selected, and the problem of uneven stress during heat treatment is reasonably improved by using multi-strand stainless steel wire for multi-directional tensioning and steel bar support, effectively reducing the bending and torsional deformation caused by heat treatment. During the free forging manufacturing stage, the raw material ingot undergoes flow deformation due to repeated forging at high temperature, resulting in temperature gradient differences inside the forging. Uneven cooling after forging causes severe fluctuations in internal stress, with the maximum residual compressive stress existing in the material edge surface layer and central area. The residual tensile stress exists in the center surface layer and the middle area of ​​the waist of the material. Based on the analysis of the residual stress distribution of aluminum alloy raw materials, before processing the rigid window frame part 4, according to the optimal layout and maximum structural contour of the rigid window frame part 4 in the forging, the stress concentration areas in the middle and around the raw material are pre-milled to release the internal stress of the raw material to a certain extent. The flexible clamping component 3 can follow the deformation trend of the rigid window frame part 4 and offset the deformation caused by gravity and the deformation generated during processing to a large extent in the vertical direction, while maintaining the clamping rigidity of the rigid window frame part 4. The conformal clamping block 2 can continuously compensate and control the shape of the rigid window frame part 4 in the longitudinal and transverse directions through multiple semi-finishing and contour corrections during the finishing process. This effectively solves the problems of large structural span of the rigid window frame part 4, difficulty in transmitting clamping force, large hollow area of ​​the rigid window frame part 4, insufficient effective support for clamping parts during clamping, and inability to use vacuum adsorption. This improves the low clamping reliability and difficulty in ensuring processing stability in the traditional rigid window frame part 4 processing process.

[0037] In this scheme, the shape control method for large-opening, thin-walled, weakly rigid window frame parts involves placing the rigid window frame part 4 in a steel frame before heat treatment. The upper part of the rigid window frame part 4 is supported by steel bars and pulled by multiple strands of steel wire ropes with zero force. The multiple strands of steel wire ropes are evenly distributed on the outer wall of the rigid window frame part 4, so that the self-weight and stress of the rigid window frame part 4 are dispersed in multiple directions after softening at high temperature, reducing the impact of heat treatment on the shape change of the rigid window frame part 4. Before rough machining, the middle and surrounding areas where the internal stress of the raw material is relatively concentrated are removed, which changes the direction of the internal stress of the large-thickness free forging and greatly reduces the weight, reducing the deformation impact of the material frame on the rigid window frame part 4 during rough machining.

[0038] By installing a limit spring 306 on the inner wall of the mounting groove 305, installing a protrusion 307 on one end of the fixing bolt 304, threading a spiral limiter 7 on the outer wall of the flexible support block 5, and opening a sliding groove 308 on the side wall of the mounting base 301, with a side stop limit bolt 8 slidably connected to the inner wall of the sliding groove 308, the flexible support block 5 is adjusted normally in the free state of the rigid window frame part 4, so that the process boss 6 is in close contact with the upper surface of the support body. At the same time, locking the spiral limiter 7 and the side stop limit bolt 8 compensates for the self-weight of the rigid window frame part 4; precision machining During machining, conformal clamping block 2 is used to fix and tighten the rigid window frame part 4, providing sufficient axial locking force so that the rigid window frame part 4 is processed in a conformal state. The coordinated cooperation between conformal clamping block 2 and flexible clamping component 3 effectively ensures the accuracy of the position and orientation of the rigid window frame part 4 during finishing, avoiding vibration caused by the poor rigidity of the large-opening thin-walled rigid window frame part 4. This solves the shortcomings of traditional shape control methods, such as incomplete stress release, long processing cycle, and difficulty in guaranteeing theoretical external dimensions, and the problem that the high-precision theoretical external shape deformation of large-opening thin-walled weak rigid window frame parts cannot be effectively controlled.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component, comprising a positioning base (1), a conformal clamping block (2), a rigid window frame component (4), a flexible support block (5), a process boss (6), a locking screw limiter (7), a side-stop limiting bolt (8), and a flexible clamping assembly (3) for positioning and adjusting the rigid window frame component (4), characterized in that: The conformal clamp (2) and flexible clamping assembly (3) fix the rigid window frame part (4) on the base surface of the positioning base (1). The flexible clamping assembly (3) includes a mounting base (301). The outer wall of the mounting base (301) is provided with a mounting hole (302). A connecting bolt (303) is installed on the inner wall of the mounting hole (302). A flexible support block (5) is installed at the port of the mounting base (301). A fixing bolt (304) is installed on the inner wall of the flexible support block (5). A mounting groove (305) is provided on one side of the fixing bolt (304) and on the inner wall of the flexible support block (5). A limit spring (306) is installed on the inner wall of the mounting groove (305). A protrusion (307) is installed at one end of the fixing bolt (304). A spiral limiter (7) is threaded on the outer wall of the flexible support block (5). A sliding groove (308) is opened on the side wall of the mounting base (301). A side stop limit bolt (8) is slidably connected on the inner wall of the sliding groove (308). A positioning groove (309) is opened on the outer wall of the mounting base (301). A protruding plate (310) is installed on the outer wall of the mounting base (301). A fixing hole (311) is opened on the outer wall of the protruding plate (310). A fixing bolt (304) is inserted and pulled on the inner wall of the fixing hole (311). A process boss (6) is installed on the outer wall of the fixing bolt (304). The specific steps are as follows: Step 1: Before heat treatment, the rigid window frame part (4) is placed in the steel frame. The upper part of the rigid window frame part (4) is supported by steel rods and pulled by multiple strands of steel wire rope with zero force. The multiple strands of steel wire rope are evenly distributed on the outer wall of the rigid window frame part (4), so that the self-weight and stress of the rigid window frame part (4) are dispersed in multiple directions after softening at high temperature, reducing the influence of heat treatment on the shape change of the rigid window frame part (4). Step 2: Remove the middle and surrounding areas where the internal stress of the raw material is concentrated, thereby changing the direction of the internal stress in the thick free forging. Step 3: Adjust the flexible support block (5) in the normal direction between each workstation while the rigid window frame part (4) is in a free state, so that the process boss (6) is in close contact with the upper surface of the support body, and at the same time tighten the spiral limiter (7) and the side stop limit bolt (8) to compensate for the self-weight of the rigid window frame part (4). During finishing, conformal clamps (2) are used to fix and tighten the rigid window frame part (4) to provide sufficient axial locking force so that the rigid window frame part (4) is processed in a conformal state.

2. The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The mounting base (301) has an L-shaped cross-section. Multiple sets of mounting holes (302) are provided and are respectively installed on the outer wall of the mounting base (301). Multiple sets of connecting bolts (303) are provided and are respectively located on the inner wall of the mounting holes (302). The connecting bolts (303) are located on one side of the protrusion (307). The flexible support block (5) has a T-shaped cross-section.

3. The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The fixing bolts (304) are provided in two sets and are located on the inner walls of the flexible support block (5) and the fixing hole (311) respectively. The mounting groove (305) is located in the inner cavity of the mounting base (301), and the limiting spring (306) is located in the inner cavity of the mounting base (301).

4. The shape control method for a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The limiting spring (306) is located on one side of the protrusion (307), the spiral limiter (7) is located directly above the mounting base (301), and one end of the side stop limiting bolt (8) passes through the slide groove (308) and extends to one side of the slide groove (308) to be connected to the flexible support block (5).

5. The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The groove (308) is located directly above the mounting hole (302), the groove (308) is located on one side of the protrusion (310), the positioning groove (309) is located on one side of the flexible support block (5), and the protrusion (310) is located at the port of the mounting base (301).

6. The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The convex plate (310) is located on one side of the flexible support block (5), the fixing hole (311) is located on one side of the flexible support block (5), and the cross-section of the conformal clamp (2) is an L-shaped structure.

7. The method for controlling the shape of a large-opening, thin-walled, weakly rigid window frame component according to claim 1, characterized in that: The outer wall of the process boss (6) is provided with a connection hole. There are two sets of connection holes, which are located on the outer wall of the process boss (6). A fixing bolt (304) is connected to the inner wall of the connection hole. The process boss (6) is located directly above the flexible support block (5).

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