Machining method for special-shaped structure of thin-wall part

Abstract

The invention discloses a method for machining a special-shaped structure of a thin-wall part, which reduces the welding difficulty and improves the welding quality. A thin-wall part is a flow guide heat insulation cover, and the method comprises the steps that a welding block positioning tool is used for scribing, the welding block positioning tool is used for positioning through reinforcing ribs on the large end face of a heat insulation cover body and the molded line of the heat insulation cover body, the positioning tool is provided with an inner hole wall corresponding to the welding position of a welding block, and the welding block positioning tool is positioned after being right and flush with the heat insulation cover body; scribing along the inner hole wall of the positioning tool by using a scribing needle; splitting the heat shield body along the marking position to form an opening; the heat insulation cover body is placed on a flanging and rounding tool, positioning is conducted through reinforcing ribs on the large end face of the heat insulation cover body and the molded line of the heat insulation cover body, the flanging and rounding tool is driven by a pressing machine, and profiling and flanging of the opening position are completed; a welding block flat and straight unfolding plate is selected and placed in a welding block profiling mold, and a press is used for profiling; and the machined welding block and the heat insulation cover body are welded after being in lap joint.

Description

Technical Field

[0001] The invention relates to the technical field of sheet metal parts processing, and in particular to a method for processing a thin-walled part with a special-shaped structure. Background Art

[0002] The turbocharger is one of the most important core supporting systems of the diesel engine. The guide and heat shield parts have complex structures and are difficult to weld. As the covering parts of the bearing shell, they play an important role in heat insulation, guide and protection, which directly affects the performance and life of the turbocharger.

[0003] The heat shield (hereinafter referred to as the heat shield) is welded together by the heat shield body, welding block and positioning ring. The materials are all SUS321 austenitic stainless steel. Figure 1 The main heat insulation cover is trumpet-shaped, and the welding block is a special-shaped structure. As the part covering the bearing shell, the protruding special-shaped structure of the welding block is to avoid the oil return pipe structure of the bearing shell. The overall part is relatively large (see the size Figure 2 , large end diameter Φ612, small end diameter Φ210, height 232), welding is difficult, and it is a thin-walled part, the welding block position is difficult to process and the welding quality is poor.

[0004] When the welding block is welded to the main body of the heat insulation cover, the mating surface is an irregular curved surface, such as Figure 3 As shown, it is difficult to ensure the matching effect by manual sheet metal processing methods, and it is easy to form a large matching gap when welding with the insulation cover, which makes welding difficult, the weld is not beautiful, and the welding quality is poor.

[0005] If the welding effect adopts the method of manual sheet metal folding, from the processing effect point of view, it is not only difficult to operate, but also requires high skills of the operator, has poor appearance and produces angular edges, which makes welding difficult, the welding quality is poor, and the local stress concentration of the parts.

[0006] If a special tool is used to directly press the heat insulation cover of the main body of the part into a protruding whole (without a welding block structure), the protruding part of the part is large, which will cause the wall of this position to be thin after molding, the thickness uniformity of the part to be poor, the strength to be low, and the failure to meet the designed use conditions. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a processing method for thin-walled parts with special-shaped structures, thereby reducing welding difficulty and improving welding quality.

[0008] The object of the present invention is achieved in that:

[0009] A method for processing a thin-walled part with a special-shaped structure, wherein the thin-walled part is a flow-guiding heat-insulating cover, and the flow-guiding heat-insulating cover has a heat-insulating cover body, comprising the following steps:

[0010] S1, line drawing

[0011] After the heat insulation cover is processed, the welding block positioning tool is used to mark the line. The welding block positioning tool is positioned by the reinforcing ribs on the large end surface of the heat insulation cover and the heat insulation cover body profile. The positioning tool has an inner hole wall corresponding to the welding position of the welding block. The welding block positioning tool is placed flat against the heat insulation cover body and positioned, and then a marking needle is used to mark along the inner hole wall of the positioning tool;

[0012] S2, opening

[0013] Use an angle grinder or laser cutting machine to cut the heat insulation cover along the marked position to form an opening. The opening position should be smooth without edges or sharp corners.

[0014] S3, Flanging round

[0015] Place the heat insulation cover on the flanging tooling, use the reinforcing ribs on the large end surface of the heat insulation cover and the heat insulation cover profile to position it, use a press to drive the flanging tooling, and complete the press flanging of the opening position to make the opening position fit the angle required for welding;

[0016] S4. Welding block processing

[0017] Use welding blocks to flatten the sheet material, place it in the welding block pressing mold, and use a press to press and fix it for 5-10 seconds to form it;

[0018] S5. Welding

[0019] Overlap the processed welding block and the heat insulation cover body and fix them by spot welding. After observation, weld the overlapping position.

[0020] Preferably, the inner surface of the welding block positioning tool is used for positioning with the insulation cover body contour, and positioning legs are respectively provided at both ends of the bottom of the welding block positioning tool, and the two positioning legs are used for positioning with the reinforcing ribs on the large end surface of the insulation cover body.

[0021] Preferably, handles are installed on both sides of the welding block positioning tool.

[0022] Preferably, an inclined surface is provided on the inner side of the positioning leg of the welding block positioning tool, and the inclined surface is used for obliquely fitting and positioning with the outer side of the corresponding reinforcing rib.

[0023] Preferably, the flanging full-circle tooling includes an upper die and a lower die. The surface of the lower die is used to cooperate and position with the profile of the heat insulation cover body. The lower die is also provided with a positioning structure and a leveling structure. The positioning structure is used to cooperate and position with the reinforcing ribs on the large end face of the heat insulation cover body, and the leveling structure is used to level the large end face of the heat insulation cover body. The upper die has a limiting module and a pressing module. The limiting module is slidably matched and sleeved on the pressing module. The limiting module is connected to the upper die through a spring mechanism. The limiting module is used to press the heat insulation cover body, and the pressing module is used to press and flanging the edge position of the opening.

[0024] Preferably, the welding block pressing die comprises an upper die punch, a fixed plate, an upper die seat, and a lower die seat. The fixed plate is mounted on the lower die seat, the upper die punch is mounted on the upper die seat, and a pressing groove is provided on the fixed plate corresponding to the upper die punch.

[0025] Preferably, the welding block is made of stainless steel and has springback deformation. The required angle after forming is 84°, and the pressing angle is 70°.

[0026] Preferably, the flow-guiding heat-insulating cover is a flow-guiding heat-insulating cover of an axial-flow supercharger for a CTA series low-speed diesel engine.

[0027] Due to the adoption of the above technical solution, the present invention designs welding block positioning tooling, welding block profiling tooling and special heat insulation cover body flanging rounding tooling, and through reasonable processing methods, the flanged part of the welding position of the part is tightly fitted with the inner and outer surfaces of the curved surface of the welding block, reducing the matching gap and thus reducing repeated welding, thereby reducing the difficulty of welding and improving the welding quality. It also realizes the smooth transition of the welding position of the welding block, improves the strength performance near the welding block of the guide heat insulation cover, and avoids the irregular connection and no smooth transition of the welding area due to artificial folding, which causes stress concentration and thus reduces the welding strength of the local area of ​​the part. The present invention has the following beneficial effects:

[0028] ① By using a special welding block press tooling, and through continuous verification, the angle and profile data of the press tooling are finally confirmed, reducing manual operation errors, ensuring the matching dimensions of the subsequent welding block and the insulation cover body, reducing welding difficulty, and improving product quality.

[0029] ② A smooth transition of the welding position of the welding block is achieved, the strength performance near the welding block of the guide heat shield is improved, and the irregular connection and non-smooth transition of the welding area caused by artificial folding are avoided, which causes stress concentration and thus reduces the welding strength of the local area of ​​the part. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the guide heat shield;

[0031] Figure 2 The following is the dimension drawing of the heat insulation cover;

[0032] Figure 3 This is a schematic diagram of the cooperation between the welding block and the main body;

[0033] Figure 4 This is a schematic diagram of the welding block positioning tooling structure;

[0034] Figure 5 A three-view schematic diagram of the welding block positioning tooling;

[0035] Figure 6 A schematic diagram of the use of the welding block positioning tool;

[0036] Figure 7 This is a schematic diagram of the structure of the welding block pressing die;

[0037] Figure 8 This is a schematic diagram of the structure of the lower die part of the flanging round tooling;

[0038] Fig. 9 This is a schematic diagram of the structure of the upper die part of the flanging round tooling;

[0039] Fig.10 It is a schematic diagram of the cooperation effect between the welding block and the heat insulation cover;

[0040] Fig.11 Schematic diagram of the fillet transition in the welding block area. DETAILED DESCRIPTION

[0041] A processing method for thin-walled parts with special-shaped structures requires tooling:

[0042] (1) Welding block positioning tool

[0043] This tooling uses the large end face reinforcement ribs of the heat insulation cover and the heat insulation cover body contour for positioning and fixing. The purpose is to accurately locate the welding position of the welding block on the main body of the guide heat insulation cover, laying the foundation for the subsequent flanging full circle position.

[0044] (2) Welding block pressing die

[0045] The welding block is a special-shaped structure. It is difficult to circle and calibrate the sheet metal manually, and the processing quality is unstable, making it difficult to meet the design requirements. Therefore, a welding block profiling die is designed. The tooling consists of a positioning plate, a fixing plate, an upper die, and a lower die. It has a simple structure and is easy to disassemble. The positioning plate is used to limit the welding block. In order to ensure the forming size of the welding block, considering its structure and the rebound deformation of the stainless steel material, the drawing requires an angle of 84° after forming. Finally, through repeated verification, it was found that the welding block can meet the design requirements after stamping when the angle of the stamping tooling die surface is 70°.

[0046] (3) Heat insulation cover body flanging round tooling

[0047] The heat insulation cover is fixed on the lower mold of the tooling by positioning and leveling through the reinforcing ribs and outer contour curve of the heat insulation cover itself. During the pressing process, the limit module of the upper mold first presses the heat insulation cover through the spring mechanism to prevent the part from being displaced during pressing, and then controls the upper mold to press slowly.

[0048] A processing method for thin-walled parts with special-shaped structures:

[0049] ① Marking: After the main part of the guide heat shield is processed, use the welding block positioning tool to mark the line. The tool is positioned using the reinforcing ribs on the large end surface of the heat shield body and the heat shield body contour line. Place the tool flat against the heat shield body and fix it, and use a marking needle to evenly mark a solid line along the inner hole wall of the positioning tool.

[0050] ② Opening: Use an angle grinder or laser cutting machine to cut the heat insulation cover along the marked position. The opening position should be smooth without edges or sharp corners.

[0051] ③ Flanging and rounding: Place the heat insulation cover on the flanging and rounding tooling, use the reinforcing ribs on the large end surface of the heat insulation cover and the heat insulation cover profile to position and fix it, use a hydraulic press to carry the tooling upper mold to press the flanging, and during the pressing process, the tooling upper mold fixing parts will first contact the heat insulation cover to fix it, so that the movement of the parts will not occur during the pressing process.

[0052] ④Welding block processing: Use welding blocks to flatten the sheet and place it in the welding block pressing mold. Use a hydraulic press to press and fix it for 5-10s to make it completely formed.

[0053] ⑤ Welding: Fix the processed welding block and the heat insulation cover by spot welding with an overlap of 10mm. This is to ensure that the welding position overlaps during full welding and improve the welding quality. After observation, weld the inner and outer circle overlap positions.

[0054] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for processing a thin-walled part with a special-shaped structure, wherein the thin-walled part is a flow-guiding heat-insulating cover, and the flow-guiding heat-insulating cover has a heat-insulating cover body, characterized in that: The following steps are involved: S1, line drawing After the heat insulation cover is processed, the welding block positioning tool is used to mark the line. The welding block positioning tool is positioned by the reinforcing ribs on the large end surface of the heat insulation cover and the heat insulation cover body profile. The positioning tool has an inner hole wall corresponding to the welding position of the welding block. The welding block positioning tool is placed flat against the heat insulation cover body and positioned, and then a marking needle is used to mark along the inner hole wall of the positioning tool; S2, opening Use an angle grinder or laser cutting machine to cut the heat insulation cover along the marked position to form an opening. The opening position should be smooth without edges or sharp corners. S3, Flanging round Place the heat insulation cover on the flanging tooling, use the reinforcing ribs on the large end surface of the heat insulation cover and the heat insulation cover profile to position it, use a press to drive the flanging tooling, and complete the press flanging of the opening position to make the opening position fit the angle required for welding; S4. Welding block processing Use welding blocks to flatten the sheet material, place it in the welding block pressing mold, and use a press to press and fix it for 5-10 seconds to form it; S5. Welding Overlap the processed welding block and the heat insulation cover body and fix them by spot welding. After observation, weld the overlapping position.

2. A method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: The inner surface of the welding block positioning tool is used to cooperate with the insulation cover body line for positioning. Positioning legs are respectively provided at both ends of the bottom of the welding block positioning tool. The two positioning legs are used to cooperate with the reinforcing ribs on the large end surface of the insulation cover body for positioning.

3. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: Handles are installed on both sides of the welding block positioning tool.

4. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: An inclined surface is provided on the inner side of the positioning leg of the welding block positioning tool, and the inclined surface is used for obliquely fitting and positioning with the outer side of the corresponding reinforcing rib.

5. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: The flanging full-circle tooling includes an upper die and a lower die. The surface of the lower die is used to cooperate and position with the profile line of the heat insulation cover body. The lower die is also provided with a positioning structure and a leveling structure. The positioning structure is used to cooperate and position with the reinforcing ribs on the large end face of the heat insulation cover body, and the leveling structure is used to level the large end face of the heat insulation cover body. The upper die has a limiting module and a pressing module. The limiting module is slidably matched and sleeved on the pressing module. The limiting module is connected to the upper die through a spring mechanism. The limiting module is used to press the heat insulation cover body, and the pressing module is used to press and flanging the edge position of the opening.

6. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: The welding block pressing die comprises an upper die punch, a fixed plate, an upper die seat and a lower die seat. The fixed plate is mounted on the lower die seat, the upper die punch is mounted on the upper die seat, and a pressing groove is provided on the fixed plate corresponding to the upper die punch.

7. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: The welding block is made of stainless steel and has springback deformation. The required angle after forming is 84°, and the pressing angle is 70°.

8. The method for processing thin-walled parts with special-shaped structures according to claim 1, characterized in that: The flow guide heat insulation cover is the flow guide heat insulation cover of the axial flow supercharger for the CTA series low-speed diesel engine.

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