Processing technology for port of caliber pipe fitting for exhaust of thermal management system

Abstract

The invention discloses a processing technology of a port of a caliber pipe fitting for exhaust of a thermal management system. The processing technology comprises the following steps: step 1, laser blanking; step 2, forming a bent pipe; 3, end opening saw cutting is carried out; step 4, bulging and rounding; 5, pipe end forming; the step 4 of bulging and rounding specifically comprises the following steps: tool connection; loading a workpiece; performing bulging action; and maintaining pressure and shaping. According to the processing technology for the port of the caliber pipe fitting, the ovality of the port of the bent pipe can be reduced to be less than 1.01 from 1.05 through radial uniform pressure application of the specially-made bulging tool, the size precision of the outer diameter is improved to phi 127 + / -0.3 mm, and the percent of pass is greater than or equal to 95%; elastic contact (non-rigid extrusion) is adopted in the bulging process, an aluminized layer is prevented from being scratched or falling off, and the corrosion resistance retention rate is larger than or equal to 98%; according to the machining process, tools are transformed based on existing pipe end forming equipment, large equipment does not need to be newly added, the single-piece machining time is shorter than or equal to 5 min, and compared with a traditional process, the efficiency is improved by 30%.

Description

Technical Field

[0001] This invention belongs to the field of precision machining technology for metal pipe fittings, specifically relating to a machining process for the port of a diameter pipe fitting used in the exhaust of a thermal management system. It is particularly suitable for correcting the out-of-roundness of the pipe diameter caused by deformation at the port of a small-radius bend and for high-precision dimensional control. Background Technology

[0002] In the field of exhaust systems for thermal management systems, pipe fittings (such as φ127*2 aluminized pipes) are key components, and both ends must meet the high precision requirement of an outer diameter of φ127±0.3mm. Figure 1 As shown. However, these types of pipe fittings are usually small-radius bends. During the bending process, due to the plastic deformation of the material and stress concentration, the pipe diameter is prone to elliptic deformation in the root area (within about 60mm), with measured outer diameter fluctuations reaching φ122-127mm, far exceeding the tolerance requirements. Traditional processing techniques mostly use mechanical rounding or secondary forming, but they have the following drawbacks: 1. Mechanical rounding easily damages the coating, leading to a decrease in corrosion resistance; 2. Secondary forming equipment has poor versatility, requiring customized molds, resulting in high costs; 3. It is impossible to accurately control the dimensional consistency after rounding, with a pass rate of less than 70%. Therefore, there is an urgent need for an efficient and low-cost end processing technology to solve the problem of elliptic deformation at the ends of small-radius bends, while ensuring coating integrity and dimensional accuracy. Summary of the Invention

[0003] Purpose of the invention: To address the problems of difficulty in correcting elliptic deformation and insufficient dimensional accuracy at the ends of small-radius bent pipes in existing technologies, this invention provides a processing technology for the ends of pipe fittings used in the exhaust of thermal management systems. By optimizing the synergistic effect of the bulging process and the pipe end forming, the invention achieves rapid rounding and high-precision dimensional control of the bent pipe ends.

[0004] Technical solution: A processing method for the port of a pipe fitting used in the exhaust of a thermal management system, comprising the following steps: Step 1, Laser Cutting: The φ127*2 aluminized tube raw material is cut to a fixed length using laser cutting equipment to avoid deviations in subsequent processing benchmarks; Step 2, pipe bending: Use a CNC pipe bending machine to cold bend small-radius pipes to control the bending radius and reduce the amount of plastic deformation at the root of the pipe. Step 3, End sawing: Use an automatic saw to saw both ends perpendicular to the axis of the bend to remove severely deformed areas at the ends of the bend and ensure that the ends to be processed are free of burrs and flash. Step 4, bulging and rounding: Using a special bulging fixture, the sawn ends are radially bulged to eliminate elliptical deformation. This specifically includes: 4.1 Tooling Connection: The bulging tooling is connected to the slide block of the tube end forming machine by screws, and moves back and forth with the slide block. At the same time, it is fixedly connected to the machine base support of the tube end forming machine by threads, and remains stationary, forming a "one moving and one stationary" matching structure. 4.2 Workpiece loading: Insert the pipe end into the inner hole of the bulging fixture, so that the deformation area completely covers the bulging section of the fixture; 4.3 Bulging action: The tube end forming machine drives the slider to move the tooling. Through the elastic bulging block or hydraulic bulging head on the inner wall of the tooling, radial uniform pressure is applied to the tube end, gradually restoring the elliptical cross section to a circle. 4.4 Pressure holding and shaping: After reaching the target size φ127±0.3mm, hold the pressure for 2-3 seconds, release the pressure and remove the tooling; Step 5, Pipe end forming: The expanded port is chamfered, widened or narrowed using a pipe end forming machine to ensure that the outer diameter of the port is φ127±0.3mm.

[0005] As a further optimization of the present invention: in step 1, laser blanking, the perpendicularity of the cut is controlled to be ≤0.5°.

[0006] As a further optimization of the present invention: in step 4, bulging and rounding, when the workpiece is loaded, the coaxiality between the pipe axis and the tooling axis is ≤0.2mm.

[0007] As a further optimization of the present invention: in step 4, bulging and rounding, when the workpiece is loaded, the deformation area is within 60mm.

[0008] As a further optimization of the present invention: in step 4, bulging and rounding, the bulging amount is controlled at 1%-3% based on the short axis before deformation.

[0009] As a further optimization of the present invention: in step 5, tube end forming, the surface roughness Ra≤1.6μm.

[0010] Beneficial effects: The specific advantages of the processing technology for the port diameter pipe fittings used in the exhaust of the thermal management system of the present invention are as follows: 1. High-precision rounding: The pipe fitting end processing technology of this invention, through the radial uniform pressure of a specially designed bulging tool, can reduce the ellipticity of the bent pipe end from 1.05 to within 1.01, improve the outer diameter accuracy to φ127±0.3mm, and achieve a pass rate of ≥95%; 2. Coating protection: The pipe fitting end processing technology of this invention adopts elastic contact (non-rigid extrusion) during the bulging process to avoid scratches or peeling of the aluminum coating, and the corrosion resistance retention rate is ≥98%; 3. High efficiency and low cost: The pipe end processing technology of this invention is based on the modification of existing pipe end forming equipment with tooling, without the need for new large equipment, and the processing time for a single piece is ≤5min, which is 30% more efficient than the traditional process; 4. High versatility: The pipe fitting end processing technology of this invention can be adapted to the end processing of pipes with diameters of φ100-φ150mm by adjusting the size of the expansion block of the expansion tool, and is applicable to a wide range of scenarios. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the pipe fitting to be processed according to the present invention; Figure 2 This is a schematic diagram of laser cutting according to the present invention; Figure 3 This is a schematic diagram of the bending forming process of the present invention; Figure 4 This is a schematic diagram of the port sawing of the present invention; Figure 5 This is a schematic diagram of the overall bulging process of the present invention; Figure 6 This is a schematic diagram of the connection between the bulging tooling and the tube end forming machine of the present invention (1-screw, 2-machine support). Figure 7 This is a schematic diagram of the workpiece loading state according to the present invention; Figure 8 This is a schematic diagram of the movement direction of the bulging tooling of the present invention (the arrow indicates the reciprocating movement direction of the slider); Figure 9 This is a schematic diagram of the tube end forming structure of the present invention. Detailed Implementation

[0012] The technical solutions in the embodiments of the present invention will be clearly and completely described below, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, 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. Example 1

[0013] like Figure 2-8 As shown, a pipe fitting end processing technology includes the following steps: Step 1, Laser Cutting: Use laser cutting equipment to cut the φ127*2 aluminized tube raw material to a fixed length, and control the perpendicularity of the cut to ≤0.5° to avoid deviation of the reference in subsequent processing; Step 2, pipe bending: Use a CNC pipe bending machine to cold bend small-radius pipes to control the bending radius and reduce the amount of plastic deformation at the root of the pipe. Step 3, End sawing: Use an automatic saw to saw both ends perpendicular to the axis of the bend to remove severely deformed areas at the ends of the bend and ensure that the ends to be processed are free of burrs and flash. Step 4, bulging and rounding: Using a special bulging fixture, the sawn ends are radially bulged to eliminate elliptical deformation. This specifically includes: 4.1 Tooling Connection: The bulging tooling is connected to the slide block of the tube end forming machine via screw 1 (which reciprocates with the slide block), and is also fixedly connected to the machine base support 2 of the tube end forming machine via threads (keeping it stationary), forming a "one moving and one stationary" mating structure; 4.2 Workpiece loading: Insert the pipe end into the inner hole of the bulging fixture, so that the deformation area (60mm range) completely covers the bulging section of the fixture, and the coaxiality between the pipe axis and the fixture axis is ≤0.1mm; 4.3 Bulging Action: The pipe end forming machine drives the slider to move the tooling. The elastic expansion block (or hydraulic expansion head) on the inner wall of the tooling applies radial uniform pressure to the pipe end, gradually restoring the elliptical cross-section to a circle. The bulging amount is controlled within 1% (based on the minor axis before deformation). 4.4 Pressure holding and shaping: After reaching the target size φ126.7mm, hold the pressure for 2 seconds, release the pressure and remove the tooling; Step 5, Pipe end forming: The expanded port is chamfered, widened or narrowed using a pipe end forming machine to ensure that the outer diameter of the port is φ126.7mm and the surface roughness Ra≤1.6μm. Example 2

[0014] A process for processing the end of a pipe fitting includes the following steps: Step 1, Laser Cutting: Use laser cutting equipment to cut the φ127*2 aluminized tube raw material to a fixed length, and control the perpendicularity of the cut to ≤0.5° to avoid deviation of the reference in subsequent processing; Step 2, pipe bending: Use a CNC pipe bending machine to cold bend small-radius pipes to control the bending radius and reduce the amount of plastic deformation at the root of the pipe. Step 3, End sawing: Use an automatic saw to saw both ends perpendicular to the axis of the bend to remove severely deformed areas at the ends of the bend and ensure that the ends to be processed are free of burrs and flash. Step 4, bulging and rounding: Using a special bulging fixture, the sawn ends are radially bulged to eliminate elliptical deformation. This specifically includes: 4.1 Tooling Connection: The bulging tooling is connected to the slide block of the tube end forming machine via screw 1 (which reciprocates with the slide block), and is also fixedly connected to the machine base support 2 of the tube end forming machine via threads (keeping it stationary), forming a "one moving and one stationary" mating structure; 4.2 Workpiece loading: Insert the pipe end into the inner hole of the bulging fixture, so that the deformation area (60mm range) completely covers the bulging section of the fixture, and the coaxiality between the pipe axis and the fixture axis is ≤0.2mm; 4.3 Bulging action: The tube end forming machine drives the slider to move the tooling. The elastic bulging block (or hydraulic bulging head) on the inner wall of the tooling applies radial uniform pressure to the tube end, gradually restoring the elliptical cross section to a circle. The bulging amount is controlled at 3% (based on the minor axis before deformation). 4.4 Pressure holding and shaping: After reaching the target size of φ127mm, hold the pressure for 3 seconds, release the pressure and remove the tooling; Step 5, Pipe end forming: The expanded port is chamfered, widened or narrowed using a pipe end forming machine to ensure that the outer diameter of the port is φ127mm and the surface roughness Ra≤1.6μm. Example 3

[0015] A process for processing the end of a pipe fitting includes the following steps: Step 1, Laser Cutting: Use laser cutting equipment to cut the φ127*2 aluminized tube raw material to a fixed length, and control the perpendicularity of the cut to ≤0.5° to avoid deviation of the reference in subsequent processing; Step 2, pipe bending: Use a CNC pipe bending machine to cold bend small-radius pipes to control the bending radius and reduce the amount of plastic deformation at the root of the pipe. Step 3, End sawing: Use an automatic saw to saw both ends perpendicular to the axis of the bend to remove severely deformed areas at the ends of the bend and ensure that the ends to be processed are free of burrs and flash. Step 4, bulging and rounding: Using a special bulging fixture, the sawn ends are radially bulged to eliminate elliptical deformation. This specifically includes: 4.1 Tooling Connection: The bulging tooling is connected to the slide block of the tube end forming machine via screw 1 (which reciprocates with the slide block), and is also fixedly connected to the machine base support 2 of the tube end forming machine via threads (keeping it stationary), forming a "one moving and one stationary" mating structure; 4.2 Workpiece loading: Insert the pipe end into the inner hole of the bulging fixture, so that the deformation area (60mm range) completely covers the bulging section of the fixture, and the coaxiality between the pipe axis and the fixture axis is ≤0.2mm; 4.3 Bulging action: The tube end forming machine drives the slider to move the tooling. The elastic bulging block (or hydraulic bulging head) on the inner wall of the tooling applies radial uniform pressure to the tube end, gradually restoring the elliptical cross section to a circle. The bulging amount is controlled at 2% (based on the minor axis before deformation). 4.4 Pressure holding and shaping: After reaching the target size φ127.3mm, hold the pressure for 2.5s, release the pressure and remove the tooling; Step 5, Pipe end forming: The expanded port is chamfered, widened or narrowed using a pipe end forming machine to ensure that the outer diameter of the port is φ127.3mm and the surface roughness Ra≤1.6μm.

[0016] The pipe fitting end processing technology of the present invention can reduce the ellipticity of the bent pipe end from 1.05 to within 1.01 by applying radial pressure uniformly through a specially designed bulging tool, and improve the outer diameter accuracy to φ127±0.3mm with a pass rate of ≥95%.

[0017] The pipe fitting end processing technology of the present invention adopts elastic contact (non-rigid extrusion) in the bulging process to avoid scratches or peeling of the aluminum coating layer, and the corrosion resistance retention rate is ≥98%.

[0018] The pipe end processing technology of the present invention is based on the modification of existing pipe end forming equipment with tooling, without the need for new large equipment, and the processing time of a single piece is ≤5min, which is 30% more efficient than the traditional process.

[0019] The pipe fitting end processing technology of the present invention can be adapted to the end processing of pipes with diameters of φ100-φ150mm by adjusting the size of the expansion block of the expansion tool, and has a wide range of applications.

Claims

1. A processing method for the port of a pipe fitting used in the exhaust of a thermal management system, characterized in that: Includes the following steps: Step 1, Laser Cutting: The φ127*2 aluminized tube raw material is cut to a fixed length using laser cutting equipment to avoid deviations in subsequent processing benchmarks; Step 2, pipe bending: Use a CNC pipe bending machine to cold bend small-radius pipes to control the bending radius and reduce the amount of plastic deformation at the root of the pipe. Step 3, End sawing: Use an automatic saw to saw both ends perpendicular to the axis of the bend to remove severely deformed areas at the ends of the bend and ensure that the ends to be processed are free of burrs and flash. Step 4, bulging and rounding: Using a special bulging fixture, the sawn ends are radially bulged to eliminate elliptical deformation. This specifically includes: 4.1 Tooling connection: The bulging tooling is connected to the slide block of the tube end forming machine by screws (1), and moves back and forth with the slide block. At the same time, it is fixedly connected to the machine base support (2) of the tube end forming machine by threads, and remains stationary, forming a "one moving and one stationary" matching structure. 4.2 Workpiece loading: Insert the pipe end into the inner hole of the bulging fixture, so that the deformation area completely covers the bulging section of the fixture; 4.3 Bulging action: The tube end forming machine drives the slider to move the tooling. Through the elastic bulging block or hydraulic bulging head on the inner wall of the tooling, radial uniform pressure is applied to the tube end, gradually restoring the elliptical cross section to a circle. 4.4 Pressure holding and shaping: After reaching the target size φ127±0.3mm, hold the pressure for 2-3 seconds, release the pressure and remove the tooling; Step 5, Pipe end forming: The expanded port is chamfered, widened or narrowed using a pipe end forming machine to ensure that the outer diameter of the port is φ127±0.3mm.

2. The processing technology for the port diameter pipe fittings used in the exhaust of a thermal management system according to claim 1, characterized in that: In step 1, laser cutting, the perpendicularity of the cut is controlled to be ≤0.5°.

3. The processing technology for the port diameter of the pipe fitting used for exhaust in a thermal management system according to claim 1, characterized in that: In step 4, during the bulging and rounding process, when the workpiece is installed, the coaxiality between the pipe axis and the tooling axis should be ≤0.2mm.

4. The processing technology for the port diameter of the pipe fitting used for exhaust in a thermal management system according to claim 1, characterized in that: In step 4, the bulging and rounding process, the deformation area is within 60mm when the workpiece is loaded.

5. The processing technology for the port diameter of the pipe fitting used for exhaust in a thermal management system according to claim 1, characterized in that: In step 4, the bulging and rounding process, the bulging amount is controlled at 1%-3% based on the short axis before deformation.

6. The processing technology for the port of the exhaust pipe for a thermal management system according to claim 1, characterized in that: In step 5, tube end forming, the surface roughness Ra ≤ 1.6 μm.

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