Triple-folding type frame and integrated welding correction machining process thereof

Abstract

The invention discloses a triple-folding frame and an integrated welding and correcting processing technology thereof.The frame is composed of a folding front fork part, a front triangular part and a rear triangular part, and the processing technology of temporary integrated welding, correcting and folding function recovery is adopted. The butt-joint mounting surfaces of the folding front fork component and the front triangular component are fixed in a multi-position spot welding mode, then the butt-joint mounting surfaces of the upper folding end faces of the front triangular component and the rear triangular component are fixed in a multi-position spot welding mode, and the three components are fixed to form a temporary overall frame structure which cannot be folded. Frame front triangle correction, frame overall correction, T4 and T6 heat treatment, machining and precision inspection are conducted in the temporary overall frame state, and the precision requirement of a single component is lowered; and after correction is completed, temporary welding spots are polished away, the folding function is recovered, the consistency of the folding effect is ensured, the working procedure is remarkably simplified, the cost is reduced, and meanwhile the yield is increased to 100%.

Description

Technical Field

[0001] The invention relates to the technical field of bicycle manufacturing, in particular to a three-folding frame and an integrated welding and correction processing technology thereof. Background Art

[0002] As a core component of portable bicycles, optimizing the manufacturing process for folding frames has always been a key focus of the industry's technological research. The current mainstream production process uses a split-processing approach, with the main processes including independent welding, straightening, painting, and final assembly of each folding component. However, this process has significant drawbacks in terms of efficiency, cost, and quality, as shown below:

[0003] 1. Split welding and correction process is cumbersome

[0004] Independent processing of multiple components: Traditional processes decompose the frame into three main independent modules: the folding front fork component, the front triangle component, and the rear triangle component. These three components are welded, corrected, and processed separately. Finally, the three components are painted separately and then assembled into a frame. For example, the folding front fork component needs to be corrected after welding separately, the sub-components of the front triangle component need to be combined and welded into sub-assemblies, and the upper and lower folding components of the rear triangle component also need to be processed in steps. Each component needs to be individually sized after welding to eliminate welding deformation and residual stress. Due to the large differences in the geometric shapes of the components, special tooling, jigs, and inspection tools need to be frequently replaced when correcting individual components, which is costly, and the operation process is repetitive and time-consuming. Moreover, after the components are assembled after size correction, the folding effect after assembly cannot be guaranteed, resulting in poor frame folding effect and low yield rate.

[0005] 2. High precision requirements drive up costs and difficulty

[0006] Separate component correction requires the design of dedicated tooling, jigs, and inspection fixtures for each component. For example, due to the complex curved structure of the folding front fork, the correction tooling must be customized to match the local curvature, which results in high cost for specialized tooling. Furthermore, after separate correction, the dimensional tolerance of each component must be strictly controlled within ±0.3mm, otherwise misalignment during assembly is likely to occur. However, the combined effects of thermal deformation during welding and tooling compatibility errors result in an actual accuracy pass rate of less than 50%, and a high rework rate.

[0007] 3. Frequent defects in the assembly process and low yield rate

[0008] During assembly of components that require separate corrections, the cumulative tolerances can cause misalignment in the folding mechanism. For example, if the axis of the folding front fork and rear triangle deviates by more than 1.0mm, the folding mechanism will become stuck or unable to lock. According to industry statistics, frames assembled using traditional processes are subject to front-to-back center alignment testing (standard deviation is <1.5mm). However, due to the cumulative errors of the separate components, the actual yield rate is less than 50%, requiring rework or scrapping of a large number of frames.

[0009] 4. Production efficiency is severely limited

[0010] The straightening process for a single vehicle frame requires sequential operation on three separate components, taking approximately two hours per frame. Including painting and assembly, the combined work for a single frame exceeds five hours, making it difficult to meet mass production requirements. Furthermore, separate straightening requires multiple straightening machines operating in parallel, with frequent tooling changes, resulting in equipment utilization rates of less than 40%, further exacerbating production bottlenecks. Summary of the Invention

[0011] In order to solve the problems of complex procedures, high costs, and low yield rates in the existing frame split correction process, the present invention provides a three-folding frame and an integrated welding correction processing process thereof. The split components are spot-welded into an integral frame for correction and processing, and the welds are then polished to restore the folding function, which significantly simplifies the process, reduces costs, and at the same time increases the yield rate to 100%.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A first aspect of the present invention provides an integrated welding and corrective processing process for a three-folding frame, the frame comprising a folding front fork component, a front triangle component, and a rear triangle component, wherein the rear end portion of the folding front fork component is rotatably docked with the front end portion of the front triangle component, the upper folding end surface of the rear end portion of the front triangle component is docked with the upper folding end surface of the front end portion of the rear triangle component, and the lower folding end surface of the rear end portion of the front triangle component is rotatably docked with the lower folding end surface of the front end portion of the rear triangle component;

[0014] The folding front fork component and the front triangle component are fixed at a plurality of spot welding locations at the butt mounting surface, and the front triangle component and the upper folding end surface of the rear triangle component are fixed at a plurality of spot welding locations at the butt mounting surface to form a temporary integral frame structure that cannot be folded;

[0015] Perform correction and machining processes in a temporary integral frame state;

[0016] After completing the above process and inspecting the accuracy to ensure it is qualified, the welding points are polished to restore the folding function before proceeding to the subsequent processing steps.

[0017] Specifically, the upper part of the front end of the folding front fork component is used to install the handlebar, and the lower part of the front end of the folding front fork component is used to install the front wheel. During normal use, the rear end of the folding front fork component and the rotational docking point of the front end of the front triangle component are fixed by the first fixing member so that the two cannot rotate relative to each other. When folding at this point, the first fixing member is opened, and the folding front fork component can be rotated horizontally backward to fold, driving the front wheel to fold horizontally backward to the front triangle component. The upper part of the front triangle component is used to install the seat, and a chain that cooperates with the front wheel and the rear wheel is installed on the front triangle component. The rear wheel can be installed on the rear triangle component. During normal use, the upper folding end surface of the rear end portion of the front triangle component and the upper folding end surface of the front end portion of the rear triangle component are fixed by the second fixing member so that the two are fixed and cannot rotate relative to each other. When folding at this point, the second fixing member is opened, and the upper folding end surface of the rear end portion of the front triangle component is separated from the upper folding end surface of the front end portion of the rear triangle component. At this time, with the connection point of the lower folding end surface of the rear end portion of the front triangle component and the lower folding end surface of the front end portion of the rear triangle component as the center, the rear triangle component can be rotated counterclockwise in a vertical plane and folded, driving the rear wheel to fold to the front triangle component.

[0018] The three-folding frame in the present application adopts the processing technology of "temporary integrated welding-correction-restoration of folding function". Specifically, the folding front fork component and the front triangle component are fixed by multiple spot welding at the butt mounting surface, and then the front triangle component and the upper folding end surface of the rear triangle component are fixed by multiple spot welding. The three components are fixed to form a temporary integral frame structure that cannot be folded. In the temporary integral frame state, the front triangle of the frame is corrected, the frame as a whole is corrected, T4 and T6 heat treatments are performed, machining and precision inspections are carried out to reduce the precision requirements of individual components. After the correction is completed, the temporary welding points are polished off, the folding function is restored, and the consistency of the folding effect is ensured.

[0019] Furthermore, the welding points at the butt-jointing surface between the folding front fork component and the front triangle component, and the welding points at the butt-jointing surface between the front triangle component and the upper folding end surface of the rear triangle component are all arranged in a plane area, and the thickness of the welding point portion is increased than the thickness of the final finished product to form a grinding allowance.

[0020] Specifically, the welding spots are set on the flat areas of the joint mounting surfaces between the components to facilitate subsequent grinding. In addition, the spot welding parts on the components are thickened to ensure that the overall appearance and structural strength are not affected during the grinding process.

[0021] Furthermore, there are three welding points at the butt-jointed mounting surface between the folding front fork component and the front triangle component, which are respectively located on the left and right sides of the top plane area of the butt-jointed mounting surface and in the middle of the bottom plane area of the butt-jointed mounting surface.

[0022] Since the front and rear sides of the docking surface between the folding front fork component and the front triangle component are the rotating assembly and the first fixing component respectively, and its arc surface structures are many, three welding points are set on the left and right sides of the top plane area of the docking surface and in the middle of the bottom plane area of the docking surface, which not only facilitates subsequent welding and grinding operations, but also ensures the fixing effect of the folding front fork component and the front triangle component after temporary welding.

[0023] Furthermore, there are five welding points at the docking mounting surface of the upper folded end surface of the front triangle component and the rear triangle component, which are respectively located on the left and right sides of the top plane area of the docking mounting surface, the middle position of the left and right side plane areas of the docking mounting surface, and the middle position of the bottom plane area of the docking mounting surface.

[0024] The front triangle component and the rear triangle component have two docking points. The lower docking point is mainly the rotation point for folding operation. Therefore, in this application, only the docking point of the upper folding end surface of the front triangle component and the rear triangle component is temporarily spot welded and fixed. In order to ensure the fixing effect of the two, five welding points are set at the docking point of the upper folding end surface of the front triangle component and the rear triangle component, which are respectively located on the left and right sides of the top plane area of the docking installation surface, the middle position of the left and right side plane areas of the docking installation surface, and the middle position of the bottom plane area of the docking installation surface.

[0025] Furthermore, the thickness of the weld spot is increased by a grinding allowance of 0.4 to 0.6 mm compared to the thickness of the final product, preferably 0.5 mm.

[0026] Furthermore, the foldable front fork component can be rotated horizontally backward to be folded.

[0027] Furthermore, the rear triangle component can be rotated and folded counterclockwise in a vertical plane with the connection point of the lower folding end surface of the rear end portion of the front triangle component and the lower folding end surface of the front end portion of the rear triangle component as the center.

[0028] Furthermore, the correction process performed in the temporary integral frame state includes correction of the front triangle of the frame and correction of the entire frame.

[0029] Correction of the front triangle of the frame includes correction of the center of the head tube and the center of the middle tube. Overall frame correction includes correction of the center of the head tube, the center of the middle tube, the straightening of the middle tube, the center of the rear axle, the center of the rear seat stay, the parallel alignment of the rear seat stay, the center of the rear chain stay, the parallel alignment of the rear chain stay, and the calibration of the mounting holes.

[0030] The front triangle of the frame is straightened after spot welding the components and before full welding. This ensures that the combined dimensions of the components after spot welding do not deviate significantly from the design. The entire frame is straightened after full welding and T4 treatment. Only after T4 treatment does the aluminum alloy soften, making it easier to shape and straighten. After straightening, T6 treatment is required to increase the strength of the aluminum alloy, making it less susceptible to deformation and breakage.

[0031] The specific operations are as follows:

[0032] Correction of the front triangle of the frame: When the front folding component is temporarily fixed, the various sub-components of the front triangle are spot welded together according to the design requirements. The front triangle is now in a whole state. The bottom bracket part of the front triangle is placed on the correction platform and fixed. Use tools such as rubber hammer and pry bar to apply external force to adjust the shape and size of the triangle to achieve the design accuracy and ensure the accuracy of the overall geometric shape of the frame.

[0033] Overall frame correction: Fix the frame's bottom bracket, use tools to apply external force to deform the frame, and ensure that the centering of the head tube, centering of the middle tube, centering of the rear axle, centering of the middle tube, centering of the rear seat fork wheel clearance, centering of the rear chain fork wheel clearance, upper fork wheel width, lower fork wheel width, upper fork parallelism, lower fork parallelism, position accuracy of each mounting hole and other related dimensional accuracy meet the design requirements.

[0034] A second aspect of the present invention provides a three-folding frame manufactured using the above process.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The three-folding frame of the present invention adopts the processing technology of "temporary integrated welding-correction-restoration of folding function". Specifically, the folding front fork component and the front triangle component are fixed by multiple spot welding at the butt mounting surface, and then the front triangle component and the upper folding end surface of the rear triangle component are fixed by multiple spot welding. The three components are fixed to form a temporary integral frame structure that cannot be folded. In the temporary integral frame state, the front triangle of the frame is corrected, the frame as a whole is corrected, T4 and T6 heat treatments are performed, machining and precision inspection are carried out to reduce the precision requirements of individual components. After the correction is completed, the temporary welding points are polished off to restore the folding function and ensure the consistency of the folding effect.

[0037] (2) The spot welding design is optimized, and the welding points are set in the flat area of the butt joint part to facilitate subsequent grinding. The thickness of the spot welding part is increased to ensure that the appearance and structural strength are not affected after grinding.

[0038] (3) The front and rear centering yield rate of the frame produced by the integrated welding correction process of the present invention is increased from less than 50% to 100%, and the need for special tooling is reduced. The cost of the correction process is reduced by more than 70%, and the correction time of a single machine is shortened from 2 hours to 0.2 hours, and the overall production efficiency is increased by 10 times; the overall correction avoids the errors of the split assembly, and the folding function is stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Figure 1 This is a schematic structural diagram of the assembled three-folding frame of the present invention;

[0041] Figure 2 Schematic diagram of the locations of welding points in the top plane area of the butt-jointed mounting surface between the folding front fork component and the front triangle component in the present invention;

[0042] Figure 3 Schematic diagram of the positions of welding points in the bottom plane area of the butt-jointed mounting surface between the folding front fork component and the front triangle component in the present invention;

[0043] Figure 4 Schematic diagram of the locations of welding points in the top plane area of the butt-jointed mounting surface of the upper folded end surfaces of the front triangle component and the rear triangle component in the present invention;

[0044] Figure 5 Schematic diagram of the positions of welding points in the side plane area of the butt-jointed mounting surface of the upper folded end surfaces of the front triangle component and the rear triangle component in the present invention;

[0045] Figure 6 Schematic diagram of the positions of welding points in the bottom plane area of the butt-jointed mounting surface of the upper folded end surfaces of the front triangle component and the rear triangle component in the present invention;

[0046] Among them, the specific drawings are marked as follows:

[0047] Fold the front fork component 1, the front triangle component 2, and the rear triangle component 3. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The embodiment of the present invention discloses an integrated welding and correction process for a three-folding frame, such as Figure 1As shown, the bicycle frame consists of a foldable front fork component 1, a front triangle component 2, and a rear triangle component 3. The rear end portion of the foldable front fork component 1 is rotatably docked with the front end portion of the front triangle component 2, the upper folding end surface of the rear end portion of the front triangle component 2 is docked with the upper folding end surface of the front end portion of the rear triangle component 3, and the lower folding end surface of the rear end portion of the front triangle component 2 is rotatably docked with the lower folding end surface of the front end portion of the rear triangle component 3; specifically, the upper part of the front end portion of the foldable front fork component 1 is used to install the handlebar, and the lower part of the front end portion of the foldable front fork component 1 is used to install the front wheel. During normal use, the rear end portion of the foldable front fork component 1 and the front end portion of the front triangle component 2 are fixed at the rotatable docking position by a first fixing member so that the two cannot rotate relative to each other. When folding, the first fixing member is opened, and the foldable front fork component 1 can be rotated horizontally backward for folding, driving the front wheel to fold horizontally backward to the front triangle component 2. The upper part of the front triangle component 2 is used to install the seat. A chain that cooperates with the front and rear wheels is installed on the front triangle component 2, and the rear wheel can be installed on the rear triangle component 3. During normal use, the upper folding end surface of the rear end portion of the front triangle component 2 is fixed to the upper folding end surface of the front end portion of the rear triangle component 3 by the second fixing member, so that the two are fixed and cannot rotate relative to each other. When folding at this point, the second fixing member is opened, and the upper folding end surface of the rear end portion of the front triangle component 2 is separated from the upper folding end surface of the front end portion of the rear triangle component 3. At this time, with the connection point of the lower folding end surface of the rear end portion of the front triangle component 2 and the lower folding end surface of the front end portion of the rear triangle component 3 as the center, the rear triangle component 3 can be rotated counterclockwise in a vertical plane and folded, driving the rear wheel to fold to the front triangle component 2.

[0050] The specific processing technology includes the following steps:

[0051] 1. Assemble the pipes and plates that make up the folding front fork component 1, fix them at a suitable position and angle using a positioning fixture, and then weld them to fix the various components of the folding front fork component 1 into a whole.

[0052] 2. Assemble the front end of the front triangle component 2 and the rear end of the folding front fork component 1, and perform multiple spot welding on the docking installation surface of the folding front fork component 1 and the front triangle component 2. Then assemble and weld the various sub-components of the front triangle component 2, such as the upper fork tube, lower fork tube and ear piece, into a whole.

[0053] 3. With the folding front fork component 1 and the front triangle component 2 temporarily spot-welded, the front triangle of the frame is corrected using specialized correction equipment. By applying external force or heating followed by cooling, the shape and size of the front triangle are adjusted to the required design accuracy, ensuring the overall geometric accuracy of the frame.

[0054] 4. The upper folding end surface of the rear end portion of the front triangle component 2 is butted against the upper folding end surface of the front end portion of the rear triangle component 3, and multiple spot welding is performed on the butting installation surface to fix it. Then, the lower folding end surface of the rear end portion of the front triangle component 2 is rotated and butted against the lower folding end surface of the front end portion of the rear triangle component 3. Subsequently, the sub-components of the rear triangle component 3 are assembled and welded into a whole to form a temporary integral frame structure that cannot be folded (the current state of the frame is similar to that of an ordinary integral frame and cannot be folded).

[0055] 5. Perform overall correction on the entire frame (check the frame's straightness, flatness, diagonal and other parameters, use hydraulic correction machine or mechanical correction equipment to adjust the frame, eliminate the stress and deformation generated during welding, and ensure the accuracy and quality of the frame), T4 treatment (submit T4 heat treatment to the frame, that is, solid solution treatment, to improve the strength and toughness of the frame, eliminate internal stress, and improve the mechanical properties of the material), re-correction (correct the frame again to eliminate deformation that may be generated during the heat treatment process to ensure the accuracy of the frame), T6 treatment (perform T6 heat treatment, that is, artificial aging treatment, to further improve the strength and hardness of the frame, and stabilize the structure and properties of the material), machining process (use lathes, milling machines, drilling machines and other machining equipment to process various parts of the frame, such as processing threaded holes, mounting holes, bearing seats, etc.), complete all processes and inspect for qualified accuracy.

[0056] 6. Grind off the excess welding points on the front folding, rear upper folding and other parts to make the surface of the frame smooth and flat. At the same time, check the folding effect to ensure that the frame is smooth and unobstructed during the folding and unfolding process, and that each folding part can fit tightly and has sufficient strength and stability.

[0057] 7. Overall painting of the frame.

[0058] 8. Remove the tooling: After painting, remove the folding tooling, check whether the frame has any deformation or damage caused by the removal of the tooling, and make necessary repairs;

[0059] Install components: Install the correct components, such as wheels, handlebars, seat, chain, etc., and ensure that each component is securely installed and functions properly;

[0060] Vehicle inspection: The assembled bicycle is inspected to check the fit of each component, folding effect, frame strength and rigidity, braking performance, gear shifting performance, etc., to ensure that the quality and safety of the bicycle meet the relevant standards and requirements.

[0061] The three-folding frame of the present invention adopts the processing technology of "temporary integrated welding-correction-restoration of folding function". Specifically, the folding front fork component 1 and the front triangle component 2 are spot-welded at multiple locations at the butt-jointing mounting surface, and then the front triangle component 2 and the upper folding end surface of the rear triangle component 3 are spot-welded at multiple locations. The three components are fixed to form a temporary integral frame structure that cannot be folded. In the temporary integral frame state, the front triangle of the frame is corrected, the frame as a whole is corrected, T4 and T6 heat treatments are performed, machining and precision inspections are performed, and the precision requirements of individual components are reduced. After the correction is completed, the temporary welding points are polished off, the folding function is restored, and the consistency of the folding effect is ensured.

[0062] The welds at the mating surfaces between the folding front fork component 1 and the front triangle component 2, as well as the welds at the mating surfaces between the front triangle component 2 and the upper folding end surface of the rear triangle component 3, are located on flat surfaces. The thickness of these welds is increased compared to the thickness of the final product to allow for grinding. Specifically, the welds are located on the flat surfaces between the components to facilitate subsequent grinding. Furthermore, the spot welds are thickened to ensure that grinding does not affect the overall appearance or structural strength.

[0063] Specifically, if Figure 2 and Figure 3 As shown, three welding points are provided at the joint mounting surface between the folding front fork component 1 and the front triangle component 2, located on the left and right sides of the top planar area of the joint mounting surface and in the middle of the bottom planar area of the joint mounting surface. Since the front and rear sides of the joint mounting surface between the folding front fork component 1 and the front triangle component 2 respectively serve as the rotating assembly and the first fixing member, which have multiple curved surface structures, the three welding points are provided on the left and right sides of the top planar area of the joint mounting surface and in the middle of the bottom planar area of the joint mounting surface. This not only facilitates subsequent welding and grinding operations, but also ensures the fixing effect of the folding front fork component 1 and the front triangle component 2 after temporary welding.

[0064] Among them, such as Figures 4 to 6As shown, there are five welding points at the joint mounting surface of the upper folding end surface of the front triangle component 2 and the rear triangle component 3, which are respectively located on the left and right sides of the top plane area of the joint mounting surface, the plane areas of the left and right side surfaces of the joint mounting surface, and the middle position of the bottom plane area of the joint mounting surface. The front triangle component 2 and the rear triangle component 3 have two joint locations, and the lower joint location is mainly the rotation location for the folding operation. Therefore, in this application, only the joint location of the upper folding end surface of the front triangle component 2 and the rear triangle component 3 is temporarily spot welded and fixed. In order to ensure the fixing effect of the two, five welding points are set at the joint location of the upper folding end surface of the front triangle component 2 and the rear triangle component 3, which are respectively located on the left and right sides of the top plane area of the joint mounting surface, the middle position of the left and right side surface areas of the joint mounting surface, and the middle position of the bottom plane area of the joint mounting surface.

[0065] The thickness of the weld spot is increased by 0.4 to 0.6 mm compared to the thickness of the final product, preferably 0.5 mm.

[0066] In another specific embodiment, the present invention further provides a three-folding frame, which is manufactured using the above process.

[0067] Experimental verification:

[0068] 1. Frame yield test:

[0069] By adopting the new process of the present invention, correction is performed when the frame is temporarily integrated, and the front and rear center deviation is strictly controlled to ≤ 0.8mm (43% better than the industry standard), thus avoiding the superposition of split errors from the root.

[0070] After adopting the new process, a factory continuously produced 5,000 frames. After 3D scanning inspection, the front and rear centering accuracy met the standards 100%, and the folding function test showed zero defects.

[0071] When using traditional processes to correct each component individually, the dimensional tolerance needs to be controlled within ±0.3mm. However, welding deformation and tooling adaptability errors cause the actual deviation to reach ±1.0mm. The pass rate of the front-to-back centering after assembly (industry standard ≤1.5mm) is less than 50%.

[0072] In a batch of 1,000 frames, 480 frames were stuck when folding because the front folding point and the rear fork axis were offset by more than 1.2mm, requiring rework or scrapping.

[0073] 2. Processing efficiency test:

[0074] Using the new process of this invention, a three-coordinate hydraulic straightening machine can perform the entire straightening process in one step, with a single straightening time of only 0.2 hours per machine. In contrast, using the traditional step-by-step process, the front folding point straightening (30 minutes), component 2 straightening (40 minutes), and component 3 upper and lower folding straightening (25 minutes each) takes a total of 2 hours per machine.

[0075] The new process in this invention allows universal tooling to fit the entire process, saving 15 minutes per vehicle. With the traditional step-by-step process, each vehicle frame requires tooling changes three times, with each change taking 5 minutes, totaling 15 minutes per vehicle.

[0076] Using the new process in this invention, the laser measuring instrument can complete the overall accuracy inspection in one go, taking 3 minutes per instrument. In contrast, using the traditional step-by-step operation, after the separate correction, three local accuracy inspections are required, taking 20 minutes per instrument.

[0077] In terms of comprehensive efficiency comparison, the total time required to correct a single frame using the process of the present invention is reduced from 155 minutes (2 hours and 35 minutes) of the traditional process to 15 minutes, and the production efficiency is increased by 10.3 times.

[0078] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An integrated welding and correction process for a three-folding frame, characterized in that: The frame is composed of a folding front fork component, a front triangle component, and a rear triangle component. The rear end of the folding front fork component is rotatably connected to the front end of the front triangle component. The upper folding end surface of the rear end of the front triangle component is connected to the upper folding end surface of the front end of the rear triangle component. The lower folding end surface of the rear end of the front triangle component is rotatably connected to the lower folding end surface of the front end of the rear triangle component. The folding front fork component and the front triangle component are fixed at a plurality of spot welding locations at the butt mounting surface, and the front triangle component and the upper folding end surface of the rear triangle component are fixed at a plurality of spot welding locations at the butt mounting surface to form a temporary integral frame structure that cannot be folded; Perform correction and machining processes in a temporary integral frame state; After completing the above process and inspecting the accuracy to ensure it is qualified, the welding points are polished to restore the folding function before proceeding to the subsequent processing steps.

2. The integrated welding and correction process for the three-folding frame according to claim 1 is characterized in that: The welding points at the butt-jointed mounting surface between the folding front fork component and the front triangle component, and the welding points at the butt-jointed mounting surface between the front triangle component and the upper folding end surface of the rear triangle component are both arranged in a plane area, and the thickness of the welding point portion is increased compared to the thickness of the final finished product to form a grinding allowance.

3. The integrated welding and correction process for the three-folding frame according to claim 2 is characterized in that: There are three welding points at the butt-jointed mounting surface between the folding front fork component and the front triangle component, which are respectively located on the left and right sides of the top plane area of the butt-jointed mounting surface and in the middle of the bottom plane area of the butt-jointed mounting surface.

4. The integrated welding and correction process for the three-folding frame according to claim 2 or 3, characterized in that: There are five welding points at the docking mounting surface of the upper folded end surface of the front triangle component and the rear triangle component, which are respectively located on the left and right sides of the top plane area of the docking mounting surface, the left and right side plane areas of the docking mounting surface and the middle position of the bottom plane area of the docking mounting surface.

5. The integrated welding and correction process for the three-folding frame according to claim 4 is characterized in that: The thickness of the weld spot is increased compared to the thickness of the final product, resulting in a grinding allowance of 0.4 to 0.6 mm.

6. The integrated welding and correction process for the three-folding frame according to claim 1 is characterized in that: The folding front fork component can be rotated horizontally backward to be folded.

7. The integrated welding and correction process for a three-folding frame according to claim 1, characterized in that: The rear triangle component can be rotated and folded counterclockwise in a vertical plane with the connection point of the lower folding end surface of the rear end portion of the front triangle component and the lower folding end surface of the front end portion of the rear triangle component as the center.

8. The integrated welding and correction process for a three-folding frame according to claim 1, characterized in that: The correction process in the temporary integral frame state includes frame front triangle correction and frame overall correction.

9. A three-folding frame, characterized in that: The method is processed by the process described in any one of claims 1 to 8.

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