CN113441907B

CN113441907B - Diesel engine exhaust manifold welding process

Info

Publication number: CN113441907B
Application number: CN202110126993.7A
Authority: CN
Inventors: 吴亚君; 任广昶
Original assignee: Suzhou Huanyu Auto Parts Co ltd
Current assignee: Suzhou Huanyu Auto Parts Co ltd
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2022-07-19
Anticipated expiration: 2041-01-29
Also published as: CN113441907A

Abstract

The invention relates to a welding process of an exhaust manifold of a diesel engine, which mainly comprises the following steps: polishing, surface tension treatment, press fitting, shaping, laser welding, various detection, packaging and warehousing and the like, most of exhaust manifolds for the existing diesel engine are multi-section exhaust manifolds, welding positions of a plurality of corrugated pipes and castings exist, the problems of low sealing performance and easy leakage are easily caused by using the traditional corrugated pipe and casting welding mode, and during welding, due to the fact that the thicknesses of the castings and the corrugated pipes are different, the welding surface is easily uneven, and the welding is wrong, so that the invention provides a novel welding process, the exhaust manifolds are welded smoothly, the air tightness is good, the automation degree is good, and batch processing production can be carried out.

Description

Diesel engine exhaust manifold welding process

Technical Field

The invention relates to the field of exhaust manifold welding mechanisms, in particular to a welding process for an exhaust manifold of a diesel engine.

Background

The exhaust manifold is a pipeline for collecting exhaust of each cylinder of an engine and discharging the exhaust together, and the existing conventional diesel engine exhaust manifold is of a plug-in type, but has certain problems, on one hand, sealing rings in a plurality of sections of the plug-in type exhaust manifold are easy to age and leak air; on the other hand, the existing exhaust manifold is mostly in hard connection, deformation is easy to generate at high temperature, and air leakage is easy to occur at the joint of the flange surface and the cylinder cover; the existing exhaust manifold is independent for each cylinder and is sealed and welded by using a metal corrugated pipe, so that the two problems are solved, but the metal corrugated pipe is a thin-wall piece, and a casting piece is a thick-wall piece, so that the corrugated pipe is melted in the traditional welding process, the casting piece is not melted, and the corrugated pipe is easily pulled and detached after being welded together.

The invention provides a method for welding the two parts together by laser welding after special process treatment, and meets the sealing requirement and the durability requirement of customers.

Disclosure of Invention

The invention aims to provide a welding process for an exhaust manifold of a diesel engine, which solves the problems of a corrugated pipe and a casting in the existing welding process.

In order to achieve the purpose, the invention adopts the technical scheme that:

a welding process of an exhaust manifold of a diesel engine is used for welding a combined exhaust manifold containing a casting and a corrugated pipe and mainly comprises the following steps:

s1, polishing, namely polishing the welding end faces of a plurality of pipe fittings to be welded;

s2, processing the welding surface material to ensure that the wetting tension of the surface of the material is not less than 36 mN/m;

s3, press fitting, namely arranging the plurality of pipe bodies in sequence and fixing the pipe bodies to ensure that the corrugated pipe and the casting do not fall off and no inward turning and gaps exist in the corrugated pipe;

s4, shaping, namely shaping the tube bodies after crimping is finished, aligning the adjacent tube bodies, and adjusting the flatness to a proper position;

s5, welding, namely, welding by using a laser welding machine to ensure that the welding surface is continuous and complete;

s6, detecting air tightness, namely detecting the air tightness of the welded exhaust manifold;

s7, detecting flatness to ensure that the integral flatness of the welded exhaust manifold is proper;

s8, detecting hole positions, namely detecting the hole positions on the surface of the exhaust manifold after welding;

s9, detecting the appearance, and detecting whether the paint is scratched or not and whether the paint is complete or not;

and S10, packaging and warehousing, spraying antirust oil, and correctly pasting the mark.

Preferably, in S2, the material surface wetting tension is tested using a dyne pen.

Preferably, in S3, the plurality of pipe bodies are press-fitted and fixed using an air cylinder having an air pressure of 0.6MPA ± 0.1 MPA.

Preferably, the power of the laser welding machine is 500-800W, and the rotating speed is 20-40 r/min.

Preferably, the surface of the welding seam in S5 is silvery white, the fusion width of the welding surface is less than 1.5mm, and the fusion depth is more than 1 mm.

Preferably, in S6, the exhaust manifold is made to be at the air pressure of 0.5MPA ± 0.05MPA for a certain period of time, and after the air outlet is blocked, there is no minute leakage inside.

Preferably, in S7, the range of flatness is less than 0.1.

Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:

the welding process is different from the traditional electric heating welding, the area influenced by the traditional electric heating welding is large, a casting is not melted when a corrugated pipe is melted, and the casting and the corrugated pipe are difficult to combine together. And then carrying out a series of tests such as air tightness test, flatness test, hole site test, appearance test and the like on the welded exhaust manifold, and finally coating rust preventive oil, then labeling, warehousing and storing. The whole operation is simple and quick, and the requirement on operators is low.

Drawings

Some specific embodiments of the invention will be described in detail hereinafter by way of example and not by way of limitation with reference to the accompanying drawings. The same reference numbers in the drawings identify the same or similar elements or components. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. In the drawings:

FIG. 1 is a block diagram of the steps of the present invention;

FIG. 2 is a schematic view of a laser welder;

FIG. 3 is a schematic structural view of a crimping tool;

fig. 4 is a schematic structural view of the airtightness detection tool.

Wherein the reference numerals are as follows:

11. a support frame; 12. a cylinder; 13. laser welding machine; 14. a rotating shaft; 15. a disc; 16. a motor; 17. a universal drive assembly;

21. a base; 22. a slide rail; 23. a bellows support frame; 24. a casting support frame; 25. a cylinder;

31. a fixing member; 32. a plugging block; 33. an air tightness detector.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1, the present invention is primarily directed to welding an exhaust manifold having a combination of a casting and a bellows, comprising the steps of:

s1, polishing the end surfaces of the casting and the corrugated pipe to be welded, and preventing the end surfaces from being uneven during welding;

and S2, processing the polished end face to ensure that the surface wetting tension of the material is not less than 36mN/m, and continuously using a dyne pen to test in the process until the surface tension of the material reaches 36mN/m and then stopping the processing.

At the step of S3, the method comprises the steps of, the pressure equipment, a plurality of bodys are arranged according to the order and fix the body, guarantee bellows and foundry goods and do not drop, do not have enstrophe and clearance in the bellows, use the crimping frock to carry out the crimping, the crimping frock includes base 21, be provided with slide rail 22 on the base 21, be provided with bellows seat and foundry goods seat on the slide rail 22, bellows seat and foundry goods seat can slide on the slide rail, be provided with bellows support frame 23 on the bellows seat, be provided with foundry goods support frame 24 on the foundry goods seat, be connected with the cylinder on bellows support frame 23 and the foundry goods support frame 24 respectively, the atmospheric pressure when opening and shutting of bellows support frame 23 and foundry goods support frame 24 and the cylinder can be controlled respectively to different cylinders 25, the atmospheric pressure control of bellows support frame 23 and foundry goods support frame 24 is between 0.6MPA 0.01MPA, can fasten bellows and foundry goods and can not make the pipe fitting crush simultaneously under this atmospheric pressure. The distance between the corrugated pipe seat and the casting seat can be adjusted by moving the corrugated pipe seat and the casting seat back and forth on the slide rail 22, the corrugated pipe seat and the casting seat are aligned with each other, and the two ends of the base are also provided with cylinders 25 for tightly abutting against the corrugated pipe seat and the casting seat to realize preliminary positioning and fastening.

S4, shaping; shaping the preliminarily positioned pipe body by using a shaping tool, wherein the shaping range comprises a hole position and a planeness position, so that the planeness range is smaller than 0.1;

s5, welding, wherein a laser welding machine is used for welding, and the laser welding machine comprises a support frame 11, a driving mechanism, a welding mechanism and a cylinder 12; the support frame 11 is provided with a plurality of rotating shafts 14, the rotating shafts 14 define a space for placing an exhaust manifold to be welded, the rotating shafts 14 are provided with a plurality of discs 15, the discs 15 are used for supporting pipe fittings, the discs 15 are provided with protrusions used for driving the corrugated pipes to rotate, the driving mechanism comprises a motor 16 used for driving the rotating shafts to rotate, the driving assembly further comprises a universal transmission set 17, and the universal rotating assembly 17 is arranged to aim at not changing the position of the motor when the position of part or all of the rotating shafts 14 is changed up and down; the both ends of pivot 14 all can slide from top to bottom, and the effect that sets up cylinder 12 can promote pivot 14 and adjust the position of pivot 14 to adapt to not the pipe fitting of equidimension and weld, welding mechanism is laser welding machine 13, can be at support frame 11 upper level and vertical removal, and vertical removal can adapt to the body of different diameters, and horizontal migration can weld the bellows and the foundry goods at different positions. The whole welding process is simple and convenient, the operation is automatic, the laser welding machine is used for processing products with different sizes, the applicability is strong, and the problems of unstable welding, uneven welding seam surface and the like caused by the traditional welding can be avoided by laser welding. The power of a laser welding machine is required to be 500-800W in the welding process, the rotating speed is 20-40 r/min, the surface of a welding line is required to be silvery white, the color shows that the protection effect is good, no other impurities exist, the fusion width of the welding surface is smaller than 1.5mm, the fusion depth is larger than 1mm, and the data can not damage the structures of the corrugated pipe and the casting under the condition of ensuring welding fastening.

S6, detecting airtightness, namely detecting the welded exhaust manifold, detecting by using an airtightness detection tool, wherein after the pore diameter is required to be blocked, the exhaust manifold lasts for no more than one minute within the air pressure range of 0.5MPA +/-0.05 MPA, and after an air outlet is blocked, the gas in the whole pipe does not leak; the air tightness detection tool comprises a fixing piece 31 and an air tightness detector 33, the fixing piece 31 fixes an exhaust manifold, then a plurality of air inlets are sealed by using a plugging block 32, and then the air tightness detector 33 is started to reach a certain air pressure range to observe whether air leaks.

And S7, carrying out flatness detection on the exhaust manifold after the tightness detection is finished, wherein the flatness range of the whole exhaust manifold is less than 0.1.

And S8, detecting the hole positions and observing whether the air outlet holes on the surface are reasonable or not. Whether the deviation is within a certain range.

And S9, appearance detection, wherein whether the surface of the exhaust manifold is scratched or knocked and whether the painted surface is complete or not is detected in the press fitting and welding processes.

And S10, performing rust prevention treatment on the exhaust manifold which is qualified by detection, coating rust prevention oil on the outer leakage coated surface for rust prevention, wherein the type of the rust prevention oil is generally WD40, pasting a correct identifier on the treated exhaust manifold, and then warehousing and storing.

During specific operation, the fine setting of partial step can be carried out according to the circumstances of reality, but holistic step is unchangeable, uses laser welding exhaust manifold compare traditional electrothermal welding airtight effect on the one hand better, can reach the durable requirement of high temperature, on the other hand has realized mechanical automation, and welding efficiency is high, and the cost of labor is lower.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the content of the present invention and implement the invention, and not to limit the scope of the invention, and all equivalent changes or modifications made according to the spirit of the present invention should be covered by the scope of the present invention.

Claims

1. A welding process of an exhaust manifold of a diesel engine is used for welding a combined exhaust manifold containing a casting and a corrugated pipe, and is characterized by mainly comprising the following steps of:

s3, press fitting, namely arranging the plurality of pipe bodies in sequence and fixing the pipe bodies to ensure that the corrugated pipe and the casting do not fall off and no inward turning and gaps exist in the corrugated pipe; the compression joint tool is used for carrying out compression joint and comprises a base, a slide rail is arranged on the base, a corrugated pipe seat and a casting seat are arranged on the slide rail, a corrugated pipe support frame is arranged on the corrugated pipe seat, a casting support frame is arranged on the casting seat, the corrugated pipe support frame and the casting support frame are respectively connected with an air cylinder, the air cylinders are also arranged at two ends of the base and tightly abut against the corrugated pipe seat and the casting seat, and preliminary positioning and fastening are realized;

s4, shaping, namely shaping the tube bodies after crimping is completed, aligning the adjacent tube bodies, and adjusting the flatness to a proper position;

s6, detecting air tightness, namely detecting the air tightness of the welded exhaust manifold; detecting by using an air tightness detection tool, wherein the air tightness detection tool comprises a fixing part, an air tightness detector and a plugging block, the fixing part fixes an exhaust manifold, the plugging block seals a plurality of air inlets, and the air tightness detector is started to reach a certain air pressure range to observe whether air leaks;

s9, appearance detection is carried out, whether the paint is scratched or knocked is detected, and whether the paint surface is complete or not is detected;

and S10, packaging and warehousing, performing rust prevention treatment, and correctly pasting a mark.

2. The diesel exhaust manifold welding process according to claim 1, wherein: in S2, the material surface wetting tension was tested using a dyne pen.

3. The diesel exhaust manifold welding process according to claim 1, wherein: at S3, the plurality of pipe bodies are press-fitted and fixed using an air cylinder having an air pressure of 0.6MPA ± 0.1 MPA.

4. The diesel exhaust manifold welding process according to claim 1, wherein: the power of the laser welding machine is 500-800W, and the rotating speed is 20-40 r/min.

5. The diesel exhaust manifold welding process according to claim 1, wherein: and the surface of the welding seam in the S5 is silvery white, the fusion width of the welding surface is less than 1.5mm, and the fusion depth is more than 1 mm.

6. The diesel exhaust manifold welding process of claim 1, wherein: in S6, the exhaust manifold is maintained at a pressure of 0.5MPA ± 0.05MPA for a period of time, and the plugging block has no internal minute leakage after plugging the air outlet.

7. The diesel exhaust manifold welding process according to claim 1, wherein: in S7, the range of flatness is less than 0.1.