Welding clamp for high-pressure oil pipe and welding method of welding clamp

Abstract

The welding clamp comprises a base, a supporting plate, two pressing mechanisms and a plurality of positioning mechanisms, the supporting plate is arranged above the base, the two pressing mechanisms are symmetrically arranged at the two ends of the supporting plate, and the positioning mechanisms are symmetrically arranged in the middle of the base; the pressing mechanism comprises a first air cylinder and a second air cylinder. The positioning mechanism comprises a clamping device and a positioning plate with a positioning hole. The welding method comprises the steps that A, a high-pressure oil pipe body and an assembly are installed on a welding clamp; b, the position of the assembly is limited through a positioning piece, and diagonal positioning of symmetrical holes is achieved; c, welding assemblies in the middle of the high-pressure oil pipe through laser welding, and then welding the assemblies from the middle to the periphery in a symmetrical welding sequence; and D, after welding is completed, the welded high-pressure oil pipe is taken out of the welding tool. Rigid constraint can be weakened, welding stress can be dispersed and reduced, and welding of the high-pressure oil pipe is simpler.

Description

Technical Field

[0001] This invention relates to the field of welding technology for high-pressure oil pipes, and more particularly to a welding fixture for high-pressure oil pipes and a welding method thereof. Background Technology

[0002] As engine technology advances towards ultra-high-pressure fuel injection, high-pressure fuel lines must withstand higher pressures while maintaining lightweight design and high reliability. This directly impacts engine power output and fuel economy.

[0003] To meet the national "dual carbon" strategy requirements and reduce harmful emissions, the high-pressure fuel line, as a core component of the fuel injection system, directly affects emission levels.

[0004] As a key component of the engine's fuel system, the fuel distribution pipe is formed into a complete fuel supply unit by welding together components such as the fuel injector mount and sensor mount. These welded points directly affect the accuracy of fuel injection and the stability of the engine, so the requirements for welding technology and material matching during manufacturing are extremely high.

[0005] When welding precision components such as high-pressure fuel lines, welding fixtures are typically used to hold the workpiece in place, ensuring the accuracy and stability of the welding position. However, traditional welding fixtures often face a series of challenges in practical applications: because the fixture design is primarily based on rigid constraints, a large fixing force is applied to the workpiece during welding. This excessive rigidity not only limits the workpiece's natural thermal deformation ability in the heat-affected zone but also easily leads to high concentration of welding stress in localized areas. This stress concentration can cause deformation problems such as bending, twisting, or localized dents. Therefore, optimizing the design of welding fixtures to reduce rigid constraints and stress concentration has become a key technical challenge for improving the welding quality of high-pressure fuel lines. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, one of the objectives of this invention is to provide a welding fixture for high-pressure oil pipes, which can reduce rigid constraints and disperse and reduce welding stress when welding high-pressure oil pipes, improve the deformation of high-pressure oil pipes during welding, and make welding simpler, thereby reducing the online rework rate and improving the first-pass yield of products. A second objective of this invention is to provide a welding method using the aforementioned welding fixture.

[0007] One of the objectives of this invention is achieved through the following technical solution: A welding fixture for high-pressure oil pipes includes a base, a support plate, two clamping mechanisms for clamping the high-pressure oil pipe body, and multiple positioning mechanisms for positioning the components to be welded. The support plate is disposed above the base, the two clamping mechanisms are symmetrically disposed at both ends of the support plate, and the multiple positioning mechanisms are symmetrically disposed in the middle of the base. The clamping mechanism includes a first cylinder for vertically pressing the high-pressure oil pipe and a second cylinder for horizontally pressing the high-pressure oil pipe. The first cylinder is disposed on the support plate, and the second cylinder is disposed on the base. The positioning mechanism includes a clamp and a positioning plate with positioning holes. The positioning plate is disposed on the base, the clamp is disposed on the positioning plate, and the positioning holes are provided with elastic positioning elements.

[0008] Preferably, the clamping mechanism further includes a sliding shaft and a slider slidably connected to the sliding shaft, the sliding shaft being fixed on the base and the support plate being disposed on the slider.

[0009] Preferably, the lower end of the base is further provided with a third cylinder for adjusting the height of the base, and the positioning mechanism further includes a fourth cylinder for positioning, the fourth cylinder being disposed on the positioning plate.

[0010] Preferably, the welding fixture further includes a first support plate and a fifth cylinder for positioning the assembly, wherein the first support plate is disposed above the support plate and the fifth cylinder is disposed on the first support plate.

[0011] The second objective of this invention is achieved by the following technical solution: A welding method using the aforementioned welding fixture includes: Step A: Install the high-pressure oil pipe body and components to be welded onto the welding fixture; Step B: Use positioning elements to limit the position of the component and achieve diagonal positioning of the symmetrical holes; Step C: First, use laser welding to weld the components in the middle of the high-pressure oil pipe, and then use a symmetrical welding sequence to weld the components from the middle to the surrounding area. Step D: After welding is completed, remove the welded high-pressure oil pipe from the welding fixture.

[0012] Furthermore, in step A, the high-pressure oil pipe body is pressed by the clamping mechanism, and the component is placed on the corresponding part of the high-pressure oil pipe body that needs to be welded.

[0013] Furthermore, in step B, a floating positioning component with elastic deformation is first used to compensate for the positioning error; then a steel positioning component forged from 45# steel is used, the surface of which is provided with a polyurethane wear-resistant layer.

[0014] Furthermore, in step C, the components are welded using lasers that alternate between long and short pulses, and the laser focus is adjusted to ensure that the weld depth of each weld point remains consistent.

[0015] Furthermore, the welding power of the laser welding is 800-1400W, and the components include an injector seat, a bracket, an oil passage seat, a sensor, or a pipe joint.

[0016] Furthermore, in step D, after welding is completed, the welded area is allowed to cool down before the positioning component is pulled out and the clamping mechanism is loosened, and finally the welded high-pressure oil pipe is removed.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The welding fixture disclosed in this application includes a clamping mechanism symmetrically arranged at both ends of the support plate and a plurality of positioning mechanisms symmetrically arranged in the middle of the base. It can evenly distribute the components to be welded on the high-pressure oil pipe body, which is conducive to first welding the components in the middle part of the high-pressure oil pipe, and then welding the components from the middle part to the periphery in a symmetrical welding sequence, thereby dispersing and reducing welding stress. In addition, the positioning plate of the welding fixture is provided with an elastic positioning element. The component to be welded is positioned by the positioning element, which can reduce rigid constraints and improve the deformation of the high-pressure oil pipe during welding, making welding simpler, thereby reducing the online rework rate and improving the first-pass yield of products. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the welding fixture of the present invention; Figure 2 for Figure 1 Enlarged structural diagram at point A; Figure 3 This is a three-dimensional structural schematic diagram of the welding fixture of the present invention from another perspective; Figure 4 This is a three-dimensional structural schematic diagram of another embodiment of the welding fixture of the present invention; Figure 5 This is a three-dimensional structural schematic diagram of another embodiment of the welding fixture of the present invention from another perspective; Figure 6 This is a flowchart of the welding method of the present invention.

[0019] In the diagram: 10. Base; 11. Third cylinder; 12. Handle; 13. Through hole; 14. Mounting hole; 20. Clamping mechanism; 21. First cylinder; 22. Second cylinder; 23. Slider; 24. Sliding shaft; 30. Positioning mechanism; 31. Positioning plate; 311. Positioning hole; 32. Clamp; 33. Fourth cylinder; 34. Positioning component; 40. Support plate; 41. First bearing plate; 411. Fifth cylinder; 42. Second bearing plate; 50. Component. Detailed Implementation

[0020] To better understand the specific technical solutions, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "left," "right," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Implementation Method 1 like Figures 1-2 As shown, in a preferred embodiment, a welding fixture for a high-pressure oil pipe includes a base 10, a support plate 40, two clamping mechanisms 20 for clamping the high-pressure oil pipe body, and a plurality of positioning mechanisms 30 for positioning the component 50 to be welded. The support plate 40 is disposed above the base 10, the two clamping mechanisms 20 are symmetrically disposed at both ends of the support plate 40, and the plurality of positioning mechanisms 30 are symmetrically disposed on the middle part of the base 10. The clamping mechanism 20 includes a first cylinder 21 for vertically pressing the high-pressure oil pipe and a second cylinder 22 for horizontally pressing the high-pressure oil pipe. The first cylinder 21 is disposed on the support plate 40, and the second cylinder 22 is disposed on the base 10. The positioning mechanism 30 includes a clamp 32 and a positioning plate 31 with a positioning hole 311. The positioning plate 31 is disposed on the base 10, the clamp 32 is disposed on the positioning plate 31, and an elastic positioning element 34 is disposed on the positioning hole 311.

[0023] In the above embodiments, the welding fixture disclosed in this application includes a clamping mechanism 20 symmetrically arranged at both ends of the support plate 40 and a plurality of positioning mechanisms 30 symmetrically arranged in the middle of the base 10. The components 50 to be welded can be evenly distributed on the high-pressure oil pipe body, which is beneficial to first weld the components 50 in the middle part of the high-pressure oil pipe, and then use a symmetrical welding sequence to weld the components 50 from the middle part to the periphery, thereby dispersing and reducing welding stress. In addition, the positioning plate 31 of the welding fixture is provided with an elastic positioning element 31. The component 50 to be welded is positioned by the elastic positioning element 31. The rigid constraint can be weakened by controlling the floating amount, which can improve the deformation of the high-pressure oil pipe during welding, thereby making the welding simpler, improving the welding accuracy, reducing the online rework rate, and improving the first-pass yield of products.

[0024] The clamping mechanism 20 includes a first cylinder 21 that vertically presses the high-pressure oil pipe body, and a second cylinder 22 that longitudinally presses the high-pressure oil pipe body. The positioning mechanism 30 includes a clamp 32 that holds the high-pressure oil pipe body or assembly 50, thus enabling omnidirectional positioning of the high-pressure oil pipe body and assembly 50 to be welded, facilitating easier welding of the high-pressure oil pipe. The support plate 40 facilitates the installation of the first cylinder 21, and the base 10 facilitates the installation of the positioning plate 31.

[0025] Implementation Method 2 like Figures 1-3 As shown, in a preferred embodiment, the clamping mechanism further includes a sliding shaft 24 and a slider 23 slidably connected to the sliding shaft 24. The sliding shaft 24 is fixed on the base 10, and the support plate 40 is disposed on the slider 23. Preferably, the lower end of the base 10 is also provided with a third cylinder 11 for adjusting the height of the base 10, and the positioning mechanism further includes a fourth cylinder 33 for positioning, which is disposed on the positioning plate 31.

[0026] In the above embodiment, the slider 23 can slide on the sliding shaft 24, causing the support plate 40 to slide (laterally), which in turn causes the first cylinder 21 to slide laterally, thereby selecting the position for pressing the high-pressure oil pipe body. The third cylinder 11 is a plug-in pin cylinder, the cylinder shaft of which can contact the floor, allowing adjustment of the height of the base 10, thus facilitating adjustment of the height of the welding fixture. The fourth cylinder 33 can press the middle of the high-pressure oil pipe body, thereby positioning the middle of the high-pressure oil pipe body and making the high-pressure oil pipe more stable. Understandably, the fourth cylinder 33 can also position the component 50.

[0027] In order to make the clamping mechanism 20 and the positioning mechanism 30 symmetrically arranged, there are four positioning mechanisms 30. The four positioning mechanisms are symmetrically arranged in pairs between the two clamping mechanisms 20, so as to position the high-pressure oil pipe body and the component 50 in all directions, and also to facilitate the symmetrical welding of the component 50 from the middle part to the surrounding area.

[0028] Implementation Method 3 like Figure 4 and Figure 5 As shown, in a preferred embodiment, the welding fixture further includes a first support plate 41 and a fifth cylinder 411 for positioning the assembly 50. The first support plate 41 is disposed above the support plate 40, and the fifth cylinder 411 is disposed on the first support plate 41.

[0029] In the above embodiment, the first support plate 41 can support a welding gun or related welding tools. The fifth cylinder 411 can press and position the component 50, which can be a sensor, connector, or other components. To better support the welding devices, a second support plate 42 is also provided on the base 10; to facilitate the extension and retraction of the cylinder shaft, a through hole 13 can be provided at the bottom of the base 10; and for heat dissipation and layout of related welding lines, a mounting hole 14 can also be provided at the bottom of the base 10.

[0030] like Figure 6 As shown, the present invention also discloses a welding method using the aforementioned welding fixture, comprising: Step A: Install the high-pressure oil pipe body and components to be welded onto the welding fixture; In step A, the high-pressure oil pipe body is pressed by the clamping mechanism 20, and the component 50 is placed on the part of the high-pressure oil pipe body that needs to be welded (corresponding component). The component includes an injector seat, bracket, oil passage seat, sensor or pipe joint, etc.

[0031] Step B: Use positioning elements to limit the position of the component and achieve diagonal positioning of the symmetrical holes; In step B, a floating positioning component with elastic deformation is first used to compensate for positioning errors; then a steel positioning component forged from 45# steel is used. The surface of the steel positioning component is wrapped with a polyurethane wear-resistant layer through hot vulcanization, which can improve durability and reduce accuracy errors caused by wear.

[0032] The positioning error is compensated by the elastic deformation of the floating positioning component, which helps to control the error fluctuation and solves the problems of large rigid constraints and difficulty in releasing thermal deformation in traditional fixtures, thereby improving positioning accuracy. Two positioning components can be used to restrict multiple degrees of freedom of the component 50, thereby achieving diagonal positioning of symmetrical holes.

[0033] Step C: First, use laser welding to weld the components in the middle of the high-pressure oil pipe, and then use a symmetrical welding sequence to weld the (required) components from the middle outwards. In step C, the laser welding can be performed using a laser welding machine. The welding torch of the laser welding machine can be mounted on (this welding fixture or) a robotic arm, and the welding torch can rotate 360° in multiple dimensions for welding. The laser welding uses alternating long and short pulses of laser light to weld components, and the focal length of the laser is adjusted to ensure that the penetration depth of each weld point is consistent, thereby improving the welding quality.

[0034] Preferably, the laser welding power is 800-1400W, and a symmetrical welding sequence is adopted, welding from the center to the periphery. This can reduce the shrinkage constraint of the weld, disperse and reduce the welding stress, thereby improving (reducing) the amount of welding deformation and enhancing the structural stability and reliability of the high-pressure oil pipe after welding.

[0035] The welding process can be divided into two steps. The first step involves component welding: some components, if complex (e.g., large branch pipes with multiple interfaces), can be disassembled into smaller components, which are then welded to their respective positions on the high-pressure oil pipe body. This can be achieved through methods such as... Figures 1-3 Welding using the welding fixture shown.

[0036] The second process involves final assembly welding: after the component welding is completed and passes inspection, final assembly welding is performed, assembling and welding the small components into the required large component, and then completing other positions or parts that require welding. This can be achieved through methods such as... Figure 4 and Figure 5 Welding using the welding fixture shown.

[0037] Step D: After welding is completed, remove the welded high-pressure oil pipe from the welding fixture.

[0038] In step D, after welding is completed, wait for the weld to cool down, then pull out the positioning component and loosen the clamping mechanism 20, and finally take out the welded high-pressure oil pipe.

[0039] In summary, the welding fixture and welding method disclosed in this application, through the symmetrical pressing mechanism 20 and positioning mechanism 30, facilitate the stacking of high-pressure oil pipes from the middle, which can reduce the shrinkage constraint of the weld and disperse and reduce welding stress; furthermore, the elastic deformation of the floating positioning component compensates for the positioning error, which helps to control the error fluctuation amount and solves the problems of large rigid constraints and difficulty in releasing thermal deformation of traditional fixtures, thereby improving the positioning accuracy and welding reliability.

[0040] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A welding fixture for high-pressure oil pipes, comprising a base, a support plate, two clamping mechanisms for clamping the high-pressure oil pipe body, and multiple positioning mechanisms for positioning the components to be welded, characterized in that: The support plate is disposed above the base, two clamping mechanisms are symmetrically disposed at both ends of the support plate, and multiple positioning mechanisms are symmetrically disposed in the middle of the base. The clamping mechanism includes a first cylinder for vertically pressing the high-pressure oil pipe and a second cylinder for horizontally pressing the high-pressure oil pipe. The first cylinder is mounted on the support plate, and the second cylinder is mounted on the base. The positioning mechanism includes a gripper and a positioning plate with a positioning hole. The positioning plate is disposed on the base, the gripper is disposed on the positioning plate, and a flexible positioning element is disposed on the positioning hole.

2. The welding fixture for a high-pressure oil pipe according to claim 1, characterized in that: The clamping mechanism further includes a sliding shaft and a slider slidably connected to the sliding shaft. The sliding shaft is fixed on the base, and the support plate is disposed on the slider.

3. The welding fixture for a high-pressure oil pipe according to claim 1, characterized in that: The lower end of the base is also provided with a third cylinder for adjusting the height of the base, and the positioning mechanism also includes a fourth cylinder for positioning, which is disposed on the positioning plate.

4. The welding fixture for a high-pressure oil pipe according to claim 1, characterized in that: The welding fixture also includes a first support plate and a fifth cylinder for positioning components. The first support plate is disposed above the support plate, and the fifth cylinder is disposed on the first support plate.

5. A welding method using the welding fixture according to any one of claims 1-4, characterized in that, include: Step A: Install the high-pressure oil pipe body and components to be welded onto the welding fixture; Step B: Use positioning elements to limit the position of the component and achieve diagonal positioning of the symmetrical holes; Step C: First, use laser welding to weld the components in the middle of the high-pressure oil pipe, and then use a symmetrical welding sequence to weld the components from the middle to the surrounding area. Step D: After welding is completed, remove the welded high-pressure oil pipe from the welding fixture.

6. The welding method according to claim 5, characterized in that, In step A, the high-pressure oil pipe body is pressed by the clamping mechanism, and the component is placed on the corresponding part of the high-pressure oil pipe body that needs to be welded.

7. The welding method according to claim 5, characterized in that, In step B, a floating positioning component with elastic deformation is first used to compensate for the positioning error; then a steel positioning component forged from 45# steel is used, and the surface of the steel positioning component is provided with a polyurethane wear-resistant layer.

8. The welding method according to claim 5, characterized in that, In step C, the components are welded using lasers that alternate between long and short pulses, and the laser focus is adjusted to ensure that the weld depth of each weld point remains consistent.

9. The welding method according to claim 8, characterized in that, The laser welding power is 800-1400W, and the components include an injector seat, a bracket, an oil passage seat, a sensor, or a pipe joint.

10. The welding method according to claim 6, characterized in that, In step D, after welding is completed, wait for the weld to cool down before pulling out the positioning component and loosening the clamping mechanism, and finally take out the welded high-pressure oil pipe.

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