A gas protection mechanism for an exhaust gas cooler laser welding tool

Abstract

The application discloses a gas protection mechanism for a laser welding tool of an exhaust gas cooler, the first gas protection component is used for providing a gas source for the second gas protection component, and the second gas protection component is used for providing gas protection for a girth weld; the first gas protection component comprises a gas connection port, a first gas protection channel, a first gas distribution channel and a first shunt channel which are sequentially connected; the second gas protection component comprises a second gas protection channel and a second gas distribution channel which are communicated; the second gas protection channel is communicated with the first shunt channel; and the first gas protection component is arranged in a base body of the welding tool, and the second gas protection component is arranged in a fixed lower part of a limiting seat of the welding tool. Through the technical scheme, all-round gas protection can be formed for a tube plate weld and a girth weld, so that the weld quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of welding technology, in particular to a gas protection mechanism of a laser welding tool for processing an automobile exhaust cooler. BACKGROUND

[0002] The exhaust cooler, namely EGR (Exhaust Gas Recirculation Cooler), is used for treating automobile exhaust to reduce the combustion temperature in the automobile engine, thereby reducing the formation of nitrogen oxides. The structure of the exhaust cooler in the prior art is shown in Figures 1-3 which includes an exhaust cooler body 100, a wing pipe 200 and a flange plate 300, the flange plate 300 is arranged at both ends of the exhaust cooler body 100, the wing pipe 200 is clamped together with the flange plates 300 arranged at both sides of the end of the cooler body 100, and then the wing pipe 200 and the flange plate 300 are processed by welding technology, thereby forming the exhaust cooler. The laser scanning welding technology is mostly used in the prior art to weld the exhaust cooler body 100, the wing pipe 200 and the flange plate 300.

[0003] However, in the prior art, there is almost no welding tool for the internal parts of the exhaust cooler, and therefore the research on how to further improve the welding quality in such welding tools is blank. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides the following technical solutions:

[0005] A gas protection mechanism for a laser welding tool of an exhaust cooler, the gas protection mechanism comprising a first gas protection assembly and a second gas protection assembly, the first gas protection assembly being used for providing a gas source for the second gas protection assembly, and the second gas protection assembly being used for providing gas protection for a girth weld; the first gas protection assembly comprises a gas inlet, a first gas protection channel, a first gas distribution channel and a first shunt channel connected in sequence; the second gas protection assembly comprises a second gas protection channel and a second gas distribution channel in communication; the second gas protection channel is in communication with the first shunt channel; and the first gas protection assembly is arranged in a base body of the welding tool, and the second gas protection assembly is arranged in a fixed lower part of a limiting seat of the welding tool.

[0006] Preferably, the first gas protection channel comprises a base body channel and a shaft channel in communication, the base body channel is arranged in the base body, and the shaft channel is arranged in a rotating shaft of the welding tool; the shaft channel, the first gas distribution channel and the first shunt channel are in communication in sequence.

[0007] Preferably, the first gas distribution channel comprises a base inner gas distribution channel, a pedestal inner gas distribution channel and a limiting seat inner gas distribution channel which are sequentially communicated; the base inner gas distribution channel is arranged in the first gas distribution assembly which comprises a first gas distribution ring sleeved on the rotating shaft of the welding tool; the pedestal inner gas distribution channel is arranged in the pedestal body of the welding tool; the limiting seat inner gas distribution channel is arranged in the limiting seat of the welding tool; the shaft channel is communicated with the base inner gas distribution channel; the first shunt channel is communicated with the limiting seat inner gas distribution channel.

[0008] Preferably, the first shunt channel comprises a second gas protection shunt channel, one end of which is communicated with the limiting seat inner gas distribution channel, and the other end is communicated with the second gas protection channel.

[0009] Preferably, the second gas distribution channel is formed by a second gas distribution assembly which comprises a main gas distribution channel and a gas distribution gap; the second gas distribution assembly comprises a second gas distribution ring and a gas distribution ring cover which is arranged inside the second opening of the welding tool and forms the gas distribution gap with the inner side of the lower pressing cover plate of the welding tool; the second gas distribution ring is sleeved on the gas distribution ring cover and forms the main gas distribution channel with the second gas distribution ring, the gas distribution ring cover and the bottom surface of the lower pressing cover plate.

[0010] Preferably, the gas protection mechanism further comprises a third gas protection assembly arranged at the lower part of the base body of the welding tool, which comprises a third gas protection interface, a third gas protection channel and a third gas distribution channel which are sequentially communicated; the third gas distribution channel comprises a connecting channel and a plurality of gas flow channels which are communicated, and the plurality of gas flow channels are communicated with the wing pipe.

[0011] Preferably, the third gas distribution channel is formed by a third gas distribution assembly which comprises a reference plate and a gas distribution sieve plate, the gas distribution sieve plate is arranged in the lower pressing plate of the welding tool, the reference plate is arranged on the lower surface of the lower pressing plate, the connecting channel is arranged in the reference plate, and the plurality of gas flow channels are arranged in the gas distribution sieve plate.

[0012] Preferably, the connecting channel comprises a first connecting channel and a second connecting channel which are sequentially communicated, the first connecting channel is arranged in the reference plate and is communicated with the third gas protection channel; the second connecting channel covers the second opening in the welding tool and is arranged on the surface of the reference plate to provide protective gas for the plurality of gas flow channels.

[0013] Preferably, the gas protection mechanism further comprises a fourth gas protection assembly, the fourth gas protection assembly comprising a fourth gas protection channel and a fourth gas distribution channel connected in sequence; the first shunt channel further comprises a fourth gas protection shunt channel, the fourth gas protection shunt channel being in communication with the gas distribution channel in the limiting seat; the fourth gas distribution channel comprises a gas distribution block channel and a gas distribution pressure cover channel in communication, the gas distribution pressure cover channel being in communication with the cooling port of the exhaust gas cooler.

[0014] Preferably, the fourth gas distribution channel is arranged in a fourth gas distribution assembly, the fourth gas distribution assembly comprising a gas distribution block and a gas distribution pressure cover, the gas distribution block channel being arranged in the gas distribution block, and the gas distribution pressure cover channel being arranged in the gas distribution pressure cover, the gas distribution pressure cover being closely fitted with the cooling port of the exhaust gas cooler.

[0015] Preferably, the fourth gas protection assembly is further provided with a pressurizing mechanism, the pressurizing mechanism comprising a crank rod, a push rod, a spring base and a striker connected in sequence, the crank rod being connected with the gas distribution block; the spring base being fixedly connected with the limiting seat in the welding tool.

[0016] Preferably, the second gas protection assembly is further provided with a positioning assembly, the positioning assembly being arranged in the lower top plate of the welding tool, the positioning assembly comprising a reference link plate and a positioning pin.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The gas protection mechanism of the present application can form all-round gas protection for the girth weld and the multiple tube sheet welds by arranging the first gas protection assembly, the second gas protection assembly, the third gas protection assembly and the fourth gas protection assembly in the welding tool, thereby improving the welding quality. Among them, the first gas protection assembly provides a protection gas source for the second gas protection assembly and the fourth gas protection assembly; the second gas protection assembly mainly provides gas protection for the girth weld at the end face of the exhaust gas cooler; the third gas protection assembly mainly forms gas protection for the inner surfaces of the multiple tube sheet welds at the A and B end faces; and the fourth gas protection assembly mainly provides gas protection for the outer surfaces of the multiple tube sheet welds at the A and B end faces and the girth weld. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 Figure 1 is a schematic diagram of the welds at the A end face of the exhaust gas cooler of the present application;

[0020] Figure 2 Figure 2 is a schematic diagram of the welds at the B end face of the exhaust gas cooler of the present application;

[0021] Figure 3 Figure 3 is a schematic diagram of the winglet pipe structure of the present application;

[0022] Figure 4 Figure 4 is a perspective view of the laser welding tool for the exhaust gas cooler of the present application;

[0023] Figure 5 The top view of the laser welding tool for the exhaust gas cooler of the present application;

[0024] Figure 6 The front view of the tool base mechanism of the present application;

[0025] Figure 7 The front view of the rotary pressing mechanism of the present application;

[0026] Figure 8 The rear view of the rotary pressing mechanism of the present application;

[0027] Figure 9 The cross-sectional view of the rotary pressing mechanism of the present application;

[0028] Figure 10 The cross-sectional structure diagram of the first gas protection assembly of the present application;

[0029] Figure 11 The cross-sectional structure diagram of the first gas protection assembly of the present application;

[0030] Figure 12 The structure diagram of the second gas protection assembly of the present application;

[0031] Figure 13 The enlarged view of the structure diagram of the second gas protection assembly of the present application;

[0032] Figure 14 The structure diagram of the third gas protection assembly of the present application;

[0033] Figure 15 The schematic diagram of the fourth gas protection assembly and the pressurizing mechanism of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] Embodiment 1:

[0036] The welding of the exhaust gas cooler in the present application includes the following contents, such as Figures 1-3As shown, the exhaust gas cooler includes a cooler body 100, small finned tubes 200, flange plates 300, and cooling inlets 400. Multiple small finned tubes 200 are arranged parallel to each other within the cooler body 100. To position the small finned tubes 200, flange plates 300 are installed at both ends of the cooler body 100, and the ends of the small finned tubes 200 are welded to the flange plates 300 to fix their position within the cooler body 100. After welding, two main types of welds are formed, such as... Figure 1 and Figure 2 As shown, there are multiple tube sheet welds 500 formed by welding the end faces of multiple small wing tubes 200 to the flange plate 300, and a circumferential weld 600 formed by the flange plate 300 and the end face of the exhaust gas cooler body 100. The number of tube sheet welds at both ends of the cooler body 100 is the same as the number of small wing tubes 200 in the exhaust gas cooler.

[0037] The gas protection mechanism involved in this invention is used in the welding fixture of automotive exhaust gas coolers to form gas protection for multiple tube sheet welds 500 and circumferential welds 600 during laser welding, so as to ensure weld quality and thus improve the welding quality of the exhaust gas cooler.

[0038] The laser welding fixture for the exhaust gas cooler, such as Figure 4 and Figure 5 As shown, it includes a tooling base mechanism 1 and a rotary clamping mechanism 2; the tooling base mechanism 1 and the rotary clamping mechanism 2 are arranged vertically, and the tooling base mechanism 1 is located after the rotary clamping mechanism 2.

[0039] like Figure 6 As shown, the tooling base mechanism 1 includes a base body 11, a torque component, and a first clamping component; the upper part of the base body is provided with a mounting hole (not shown in the figure), the torque component passes through the mounting hole and is connected to the rotary clamping mechanism 2; the first clamping component is located at the bottom of the base body 11 to clamp the exhaust gas cooler.

[0040] The torque assembly provides torque to the rotary clamping mechanism 2 to rotate it. It includes a torque drive device located on the back of the base body 11 and a torque transmission assembly located on the corresponding position on the front of the base body 11. The torque drive device passes through the mounting hole and connects to the torque transmission assembly. The torque transmission assembly includes a rotating shaft 122 and a torque connector 123. The torque connector 123 is connected to the rotating shaft 122, which passes through the mounting hole and connects to the rotary clamping mechanism 2.

[0041] Specifically, such as Figure 6As shown, the first pressing assembly comprises a pressing plate 131, a jacking assembly and a first pressing driving device 134; the pressing plate 131 and the jacking assembly are arranged on the front face of the base body 11, wherein the pressing plate 131 is arranged at the bottom of the base body 11; the jacking assembly comprises a jacking guide rail 132, and the pressing plate 131 moves up and down along the jacking guide rail 132 under the driving of the first pressing driving device 134. The first pressing driving device is arranged on the back face of the base body 11, penetrates through the base body 11 and is connected with the pressing plate 131, and the working of the first pressing driving device 134 enables the pressing plate 131 to move up and down along the jacking guide rail 132, so as to position the rotary clamping mechanism 2 in the two directions of 0° and 180°.

[0042] As shown in the figure, Figures 7-9 As shown, the rotary clamping mechanism 2 comprises a base body 21, a limiting seat 22, a rotating assembly, a second pressing assembly and a rotary clamping assembly. The base body 21 and the limiting seat 22 are connected in the horizontal direction, and both the base body 21 and the limiting seat 22 can rotate synchronously with the rotating shaft 122.

[0043] The rotating assembly is arranged in the base body 21 and is connected with the torsion assembly, which is used to provide the rotating force of the torsion assembly to the rotary clamping mechanism 2, so as to ensure that the rotary clamping mechanism 2 can start or stop rotating under the driving of the torsion assembly. As shown in the figure, Figure 8 As shown, the rotating assembly comprises a rotating shaft through hole 231, a rotating bearing 232 and a rotating connecting piece 233, the rotating shaft through hole 231 is arranged in the base body 21, and the position of the rotating shaft through hole 231 on the base body 21 corresponds to the mounting hole, so that the rotating shaft 122 can penetrate into the rotating shaft through hole 231 to provide driving force for the rotation of the base body 21 and the limiting seat 22. The rotating bearing 232 is arranged in the rotating shaft through hole 231, the rotating shaft 122 is connected with the rotating bearing 232, and the rotating bearing 232 is connected with the base body 21 through the rotating connecting piece 233, so that the connection between the rotating shaft 122 and the rotating bearing 232 is more firm.

[0044] As shown in the figure, Figure 7As shown, the limiting seat 22 is used to accommodate the exhaust gas cooler, and the welding process is completed on the limiting seat 22. The limiting seat 22 comprises a movable upper part and a fixed lower part 220, the movable upper part is provided with a left side plate 221, a right side plate 222 and an upper top plate 241; the fixed lower part 220 is connected with the lower end of the base body 21, and is provided with a lower top plate 244; and a cooler accommodating cavity 223 is formed between the left side plate 221, the right side plate 222, the upper top plate 241 and the lower top plate 244, and is used for placing the exhaust gas cooler. The upper top plate 241 is provided with an upper pressing cover plate 242 and a first opening 243 arranged in the upper pressing cover plate 242; and the lower top plate is provided with a lower pressing cover plate 244 and a second opening 245 arranged in the lower pressing cover plate 244.

[0045] In work, after the exhaust gas cooler is positioned in the accommodating cavity 223, the first pressing assembly is started to press the lower end face of the exhaust gas cooler, then the displacement mechanism is started to move the movable upper part of the limiting seat 22 to press the other end face of the exhaust gas cooler; after welding is completed, the pressing actions of the first pressing assembly and the second pressing assembly are released; then the torsion assembly is started to drive the base body 21 and the limiting seat 22 to rotate 180°, and then the first pressing assembly and the second pressing assembly are respectively started to press, and then welding of the other end face is performed.

[0046] The gas protection mechanism of the present application is designed based on the above laser welding tool, as shown in the accompanying drawings, Figures 10-14 As shown, the gas protection mechanism comprises a first gas protection assembly and a second gas protection assembly. The first gas protection assembly is arranged in the tool base mechanism 1, and the second gas protection assembly is arranged in the rotary clamping mechanism 2.

[0047] As shown in the accompanying drawings, Figure 10 And Figure 14 The first gas protection assembly is arranged in the base body 11, and is used for introducing external protection gas into the laser welding tool, so as to provide a gas source for the second gas protection assembly, and the second gas protection assembly is used for forming gas protection around the outer surface of the tube plate weld 400 and the girth weld 500. The first gas protection assembly comprises a gas inlet port 411, a first gas protection channel, a first gas distribution channel and a first shunt channel (not marked in the figure) which are sequentially communicated.

[0048] The gas inlet port 411 is arranged on the base body 11, and is used for providing an external gas source for the second gas protection assembly. Further, in order to conveniently and quickly provide protection gas or cut off the protection gas for the welding tool, the gas inlet port 411 can be designed in the form of a quick connector.

[0049] The first gas protection passage comprises a base body passage 412 arranged in the base body 11 and a shaft passage 413 arranged in the rotating shaft 122; the gas flowing into the rotating shaft 122 through the shaft passage 413 from the gas inlet 411; the first gas distribution passage comprises a base inner gas distribution passage, a base body inner gas distribution passage (not shown in the figure) and a limiting seat inner gas distribution passage (not shown in the figure) which are sequentially communicated; the base inner gas distribution passage and the base body inner gas distribution passage are arranged in the base body 21; the limiting seat inner gas distribution passage is arranged in the limiting seat 22; the first shunt passage is also arranged in the limiting seat, preferably in the fixed lower part of the limiting seat and is communicated with the limiting seat inner gas distribution passage.

[0050] The first gas protection assembly comprises a first gas distribution assembly which comprises a first gas distribution ring 415; the base inner gas distribution passage is arranged in the first gas distribution ring 415; the first gas distribution ring 415 is sleeved on the rotating shaft 122; the protective gas sequentially flows into the base body 21 and the limiting seat 22 through the shaft passage 413 arranged in the rotating shaft 122 and the base inner gas distribution passage arranged in the first gas distribution ring 415, thereby providing gas protection for laser welding. The first shunt passage comprises a second gas protection shunt passage; the protective gas can flow into the second gas protection assembly through the second gas protection shunt passage, thereby providing gas protection for the weld.

[0051] In operation, after the protective gas is connected to the gas inlet 411, the protective gas flows into the shaft passage 413 of the rotating shaft 122 through the base body passage 412, then sequentially flows through the base inner gas distribution passage in the first gas distribution ring 415, the base body inner gas distribution passage in the base body and the limiting seat inner gas distribution passage in the limiting seat, and finally flows into the second gas protection assembly through the second gas protection shunt passage.

[0052] Further, the shaft passage 413 is a "T" shaped three-way joint in the rotating shaft, wherein the horizontal part of the "T" is respectively used for communicating with the base body passage 412 at 0° and 180°; and the vertical part of the "T" is connected to the base inner gas distribution passage. In addition, the first gas distribution assembly further comprises a sealing member 416 arranged between the rotating shaft 122 and the torsion connecting member 123 to avoid the protective gas in the shaft passage 413 from overflowing. The sealing member 416 can be selected as a plug.

[0053] As shown in Figures 13-15 The second gas protection assembly is arranged in the rotating clamping mechanism 2 and is used for supplying inert gas to the outer surface of the small wing pipe 200 and the flange plate 300 to be welded, thereby providing gas protection for the outer surface of each pipe plate weld and the periphery of the girth weld between the external small wing pipe 200 and the flange plate 300.

[0054] The second gas protection assembly is arranged in the fixed lower part 220 of the limiting seat 22, and includes a second gas protection channel (not shown in the figure) and a second gas distribution channel. One end of the second gas protection channel is communicated with the first gas distribution channel, so that the protective gas can flow into the limiting seat 22 from the gas inlet 411. Specifically, one end of the second gas protection channel is communicated with the second gas protection shunt channel, and the other end is communicated with the second gas distribution channel, so that the protective gas can accurately reach the welding position through the second gas distribution channel to form protection for the girth weld.

[0055] Further, the second gas distribution channel includes a main gas distribution channel 421 and a gas distribution gap 422 which are communicated and formed by the second gas distribution assembly. The second gas distribution assembly includes a second gas distribution ring 423 and a gas distribution ring cover 424 which is arranged inside the second opening 246 of the lower pressing cover plate 245. The gas distribution ring cover 424 and the second gas distribution ring 423 are both provided with through holes, and the shape of the through hole in the gas distribution ring cover 424 is consistent with the shape of the second opening 246. A gap is arranged between the gas distribution ring cover 424 and the inner side of the lower pressing cover plate 245 to form the gas distribution gap 422, so that the protective gas can be sprayed out of the gas distribution gap 422; the second gas distribution ring 423 is sleeved on the gas distribution ring cover 424, and the main gas distribution channel 421 is formed by the second gas distribution ring 423, the gas distribution ring cover 424 and the bottom surface of the lower pressing cover plate 245. When the protective gas flows to the gas distribution gap 422 through the main gas distribution channel 421 and is sprayed out of the gas distribution gap 422, the girth weld 600 can be protected by the gas.

[0056] In operation, the rotary clamping mechanism 2 aligns the welding end surface of the exhaust gas cooler with the girth weld 600 with the second opening 246, connects the protective gas source to the gas inlet 411, and the protective gas flows to the first gas protection channel through the first gas protection channel, then flows into the second gas protection channel in the second gas protection assembly, and then flows into the main gas distribution channel 421, and the protective gas flows into the gas distribution gap 422 through the main gas distribution channel 421, and the protective gas is sprayed out of the gas distribution gap 422, thereby forming gas protection for the girth weld.

[0057] Further, the gas distribution ring cover 424 includes a horizontal part and a vertical part, so that the cross section of the gas distribution ring cover 424 is in the shape of "L", wherein the vertical part of the gas distribution ring cover 424 extends into the inner wall of the second opening 246 of the lower pressing cover plate 245, so that the vertical part of the gas distribution ring cover 424 and the inner side of the lower pressing cover plate 245 form the gas distribution gap 422; the second gas distribution ring 423 is sleeved on the horizontal part of the gas distribution ring cover 424, and a certain height difference is formed between the lower surface of the lower pressing cover plate 245 and the horizontal part of the gas distribution ring cover 424, and at this time, the main gas distribution channel 421 is formed by the side surface of the second gas distribution ring 423, the lower surface of the lower pressing cover plate 245 and the horizontal part of the gas distribution ring cover 424.

[0058] In addition, the gas protection mechanism further includes a third gas protection assembly, as shown inFigure 13 As shown, the third gas protection assembly is arranged in the lower part of the base body 11 of the tool base mechanism 1, which is used to introduce protective gas from the bottom of the waste gas cooler, so that the protective gas fills the small wing pipe 200, thereby forming internal and external gas protection for the multiple pipe plate welds of the small wing pipe 200 and the flange plate 300 during welding.

[0059] The third gas protection assembly includes a third gas protection interface, a third gas protection channel 431, and a third gas distribution channel 432. The third gas protection interface is arranged in the lower part of the base body 11 and is used to connect an external gas source; the third gas protection channel 431 is arranged in the lower part of the base body 11 and is in communication with the third gas distribution channel 432. The third gas distribution channel 432 includes a connection channel and a plurality of gas flow channels 4323; the protective gas flow of the third gas protection channel passes through the connection channel to the plurality of gas flow channels 4323, and then the protective gas uniformly flows into each small wing pipe 200 through the plurality of gas flow channels 4323. The connection channel includes a first connection channel 4321 and a second connection channel 4322 that are in communication with each other.

[0060] Specifically, the third gas distribution channel 432 is formed by a third gas distribution assembly. The third gas distribution assembly includes a reference plate 433 and a gas distribution sieve plate 434; the gas distribution sieve plate 434 is arranged in the pressing plate 131 and completely covers the second opening 246; the reference plate 433 is arranged on the lower surface of the pressing plate 131 and can move synchronously with the pressing plate 131. The connection channel is arranged in the reference plate 433, the first connection channel 4321 is arranged in the reference plate 434, and the second connection channel 4322 is arranged on the surface of the pressing plate 131, specifically in the groove on the surface of the pressing plate 131, and the second connection channel 4322 completely covers the second opening 246 in the lower cover plate 245. The position of the second connection channel 4322 corresponds to the gas distribution sieve plate 434 arranged in the pressing plate 131, the gas distribution sieve plate 434 is provided with a plurality of through holes to form a plurality of gas flow channels 4323, and the number of the plurality of gas flow channels 4323 is greater than or equal to the number of the small wing pipes 200.

[0061] When working, the first pressing driving device 134 is driven to move the distribution sieve plate 434 and the reference plate 433 synchronously with the pressing plate 131 to the second opening 246 and close to it, then the external gas source is connected to the welding tool through the third gas protection interface, the protection gas flows through the third gas protection channel 431, the first connecting channel 4321, the second connecting channel 4322, the multi-gas flow channel 4323 in the distribution sieve plate 434, and then into each small wing pipe 200, so as to form gas protection on the inner surface of the pipe plate weld. After the welding of one end face of the waste gas cooler is completed, the first pressing driving device 134 is driven again to move the third gas protection assembly away from the second opening 246; then the torsion assembly is driven to rotate the rotary clamping mechanism by 180°, at this time the upper top plate 241 faces downward, and then the first pressing driving device 134 is started again to make the third gas protection assembly close to the first opening 243, and form gas protection on the welding port of the other face of the waste gas cooler after the welding starts.

[0062] Embodiment 2

[0063] Since the second gas protection assembly is used to protect the annular weld, and the protection gas of the third gas protection assembly flows out from the inside of the small wing pipe 200, the protection of the weld by the second and third gas protection assemblies is insufficient during the welding of the small wing pipe 200 and the flange plate 300.

[0064] The difference between this embodiment and embodiment 1 is that a fourth gas protection assembly is further arranged in the gas protection mechanism, and the fourth gas protection assembly is arranged in the rotary clamping mechanism 2 to form all-around protection on the pipe plate weld 500 and the annular weld 600.

[0065] As shown in Figure 15 , the fourth gas protection assembly includes a fourth gas protection channel (not shown in the figure) and a fourth gas distribution channel. The fourth gas protection channel is arranged in the fixed lower part 220 of the limiting seat 22, and the first gas protection assembly provides an external gas source for the fourth gas protection channel. The fourth gas protection assembly is in communication with the first gas distribution channel in the first gas protection assembly. Specifically, the first shunt channel in the first gas distribution channel further includes a fourth gas protection shunt channel (not shown in the figure), one end of the fourth gas protection channel is in communication with the fourth gas protection shunt channel, and the other end is in communication with the fourth gas distribution channel.

[0066] The fourth gas distribution channel includes a gas distribution block channel and a gas distribution gland channel 441, one end of the gas distribution block channel is in communication with the fourth gas protection channel, and the other end is in communication with the gas distribution gland channel; the gas distribution gland channel 441 is in communication with the cavity of the waste gas cooler body 100 through the cooling port 400 of the waste gas cooler.

[0067] Further, the fourth gas distribution channel is arranged in a fourth gas distribution assembly, which comprises a gas distribution block 442 and a gas distribution cover 443. The gas distribution block channel is arranged in the gas distribution block 442, the gas distribution cover channel 441 is arranged in the gas distribution cover 443, one end of the gas distribution block 442 is connected with the gas distribution cover 443, and the other end is connected with the fixed lower part 220 of the limiting seat 22.

[0068] In operation, the gas distribution cover 443 is completely attached to the cooling port 400 of the exhaust gas cooler by rotating the gas distribution block 442, then the protective gas flows into the gas distribution cover channel through the fourth gas protection channel and the gas distribution block channel, and finally flows into the main body 100 of the exhaust gas cooler through the cooling port 400, so that the main body 100 of the exhaust gas cooler is filled with protective gas, thereby providing more comprehensive protection for the outer surface of the tube sheet weld during welding.

[0069] Embodiment 3:

[0070] The difference between this embodiment and Embodiments 1 or 2 is that the fourth gas protection assembly is further provided with a pressurizing mechanism for rotating the fourth gas distribution assembly and keeping the gas distribution cover 442 always precisely attached to the cooling port 400 of the exhaust gas cooler.

[0071] As shown in Figure 7 , Figure 9 and Figure 15 , the pressurizing mechanism is arranged on the side of the lower top plate 244 and comprises a curved rod 451, a push rod 452, a spring base 453 and a striker 454 connected in sequence. The curved rod 451 is connected with the gas distribution block 442, the spring base 453 is provided with an elastic member 455, the striker 454 and the push rod 452 are both connected with the elastic member 455, and the spring base 453 is fixedly connected with the side of the lower top plate 244.

[0072] In operation, the striker is hit to compress the spring base, then the push rod is pushed forward by the elastic member in the spring base, and then acts on the curved rod to rotate the curved rod so as to attach the gas distribution cover to the cooling port of the exhaust gas cooler. After welding is completed, the striker is hit again to make the striker pop out of the spring base, and under the driving of the elastic member, the push rod moves backward and simultaneously drives the curved rod to rotate so as to move the gas distribution cover away from the cooling port of the exhaust gas cooler, thereby dismounting the exhaust gas cooler from the welding tool.

[0073] Embodiment 4:

[0074] The difference between this embodiment and Embodiments 1 or 2 or 3 is that the second gas protection assembly is further provided with a positioning assembly, as shown in Figure 13As shown, the positioning assembly is arranged on the side of the lower top plate 244 facing the accommodating cavity 223, and is used to guide and position the exhaust gas cooler arranged in the accommodating cavity 223, so that the port of the exhaust gas cooler is aligned with the second opening 246. The positioning assembly comprises a reference link plate 425 and a positioning pin 426. The reference link plate 425 is provided with a reference opening (not shown in the figure) which is in the same shape as the second opening 246 in the lower cover plate 245 and is arranged on the side of the lower top plate 244 facing the accommodating cavity 223. In addition, a groove is formed in the lower top plate 244 for accommodating the reference link plate 425. The reference link plate 425 is fixedly connected with the lower top plate 244 through the positioning pin 426, and the other end of the positioning pin 426 extends out of the reference link plate 425 for guiding and positioning the exhaust gas cooler. Preferably, the positioning pin 426 is a tapered positioning pin.

[0075] In summary, the first gas protection assembly, the second gas protection assembly, the third gas protection assembly and the fourth gas protection assembly can form all-around gas protection for the girth weld 600 and the plurality of tube sheet welds 500.

[0076] It should be noted that the technical features in the above-mentioned embodiments 1 to 4 can be combined in any manner, and the technical solutions formed by the combination all fall within the protection scope of the present application. In this document, terms such as “comprise”, “contain” or any other variants are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement “comprises a” does not exclude the presence of another identical element in the process, method, article or device comprising the element.

[0077] Although the embodiments of the present application have been shown and described, it should be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A gas shielding mechanism for an exhaust gas cooler laser welding tool, the gas shielding mechanism comprising a first gas shield assembly and a second gas shield assembly, characterized in that, The first gas protection assembly is used to provide a gas source for the second gas protection assembly, and the second gas protection assembly is used to provide gas protection for the girth weld; the first gas protection assembly comprises a gas inlet, a first gas protection channel, a first gas distribution channel and a first shunt channel connected in sequence; the second gas protection assembly comprises a second gas protection channel and a second gas distribution channel in communication; the second gas protection channel is in communication with the first shunt channel; and the first gas protection assembly is arranged in the base body of the welding tool, and the second gas protection assembly is arranged in the fixed lower part of the welding tool limiting seat; The exhaust gas cooler comprises a cooler main body, a plurality of small wing pipes, flange plates and cooling openings, wherein the plurality of small wing pipes are arranged in parallel in the cooler main body, flange plates are arranged at both ends of the cooler main body, and the pipe openings at both ends of the small wing pipes are welded to the flange plates, so as to obtain a plurality of pipe plate welds formed by the end faces of the plurality of small wing pipes and the flange plates, and a girth weld formed by the flange plates and the end faces of the cooler main body. The welding tool further comprises a tool base mechanism, a rotary clamping mechanism and a torsion assembly for providing a torsion for the rotary clamping mechanism, and the torsion assembly comprises a rotary shaft connected with the rotary clamping mechanism and a torsion connecting piece connected with the rotary shaft; the tool base mechanism and the rotary clamping mechanism are arranged vertically, and the tool base mechanism is arranged behind the rotary clamping mechanism. The rotary clamping mechanism comprises a base body, a limiting seat, a rotary assembly and a rotary clamping assembly, the base body and the limiting seat are connected in the horizontal direction, and both the base body and the limiting seat can rotate synchronously with the rotary shaft, and the rotary assembly is arranged in the base body and connected with the torsion assembly. The limiting seat is used to accommodate the exhaust gas cooler and complete the welding process on the limiting seat, and the limiting seat comprises a movable upper part and a fixed lower part, the movable upper part is provided with a left side plate, a right side plate and an upper top plate, the fixed lower part is connected with the lower end of the base body and is provided with a lower top plate, and an exhaust gas cooler accommodating cavity is formed between the left side plate, the right side plate, the upper top plate and the lower top plate, for placing the exhaust gas cooler, an upper pressing cover plate is arranged in the upper top plate, and a first opening is arranged in the upper pressing cover plate, a lower pressing cover plate is arranged in the lower top plate, and a second opening is arranged in the lower pressing cover plate. The first gas protection channel comprises a base body channel and a shaft channel in communication, the base body channel is arranged in the base body, and the shaft channel is arranged in the rotary shaft of the welding tool; the shaft channel, the first gas distribution channel and the first shunt channel are in communication in sequence.

2. The gas shielding mechanism according to claim 1, wherein The first gas distribution channel comprises a base inner gas distribution channel, a base body inner gas distribution channel and a limiting seat inner gas distribution channel in communication in sequence; the base inner gas distribution channel is arranged in the first gas distribution assembly, the first gas distribution assembly comprises a first gas distribution ring, and the first gas distribution ring is sleeved on the rotary shaft of the welding tool; the base body inner gas distribution channel is arranged in the base body of the welding tool, and the limiting seat inner gas distribution channel is arranged in the limiting seat of the welding tool; the shaft channel is in communication with the base inner gas distribution channel, and the first shunt channel is in communication with the limiting seat inner gas distribution channel.

3. The gas shielding mechanism according to claim 2, wherein The first shunt passage comprises a second gas protection shunt passage, one end of which is communicated with the gas distribution passage in the limiting seat, and the other end is communicated with the second gas protection passage.

4. The gas shielding mechanism according to claim 1, wherein The second gas distribution passage is formed by a second gas distribution assembly, which comprises a main gas distribution passage and a gas distribution gap; the second gas distribution assembly comprises a second gas distribution ring and a gas distribution ring cover, which is arranged inside the second opening of the welding tool, and the gas distribution gap is formed between the gas distribution ring cover and the inner side of the pressing cover plate of the welding tool; the second gas distribution ring is sleeved on the gas distribution ring cover, and the main gas distribution passage is formed by the second gas distribution ring, the gas distribution ring cover and the bottom surface of the pressing cover plate.

5. A gas guard mechanism according to any one of claims 1 to 4, wherein The gas protection mechanism further comprises a third gas protection assembly arranged at the lower part of the base body of the welding tool, which comprises a third gas protection interface, a third gas protection passage and a third gas distribution passage communicated in sequence; the third gas distribution passage comprises a connecting passage and a plurality of gas flow passages communicated; the plurality of gas flow passages are communicated with the wing pipe.

6. The gas shielding mechanism according to claim 5, wherein The third gas distribution passage is formed by a third gas distribution assembly, which comprises a reference plate and a gas distribution sieve plate; the gas distribution sieve plate is arranged in the pressing plate of the welding tool, and the reference plate is arranged on the lower surface of the pressing plate; the connecting passage is arranged in the reference plate, and the plurality of gas flow passages are arranged in the gas distribution sieve plate.

7. The gas shielding mechanism according to claim 6, wherein The connecting passage comprises a first connecting passage and a second connecting passage communicated in sequence; the first connecting passage is arranged in the reference plate and communicated with the third gas protection passage; the second connecting passage covers the second opening of the welding tool and is arranged on the surface of the reference plate to provide protective gas for the plurality of gas flow passages.

8. The gas shielding mechanism according to claim 5, wherein The gas protection mechanism further comprises a fourth gas protection assembly, which comprises a fourth gas protection passage and a fourth gas distribution passage communicated in sequence; the first shunt passage further comprises a fourth gas protection shunt passage communicated with the gas distribution passage in the limiting seat; the fourth gas distribution passage comprises a gas distribution block passage and a gas distribution gland passage communicated; the gas distribution gland passage is communicated with the cooling port of the waste gas cooler.

9. The gas shielding mechanism according to claim 8, wherein The fourth gas distribution passage is arranged in a fourth gas distribution assembly, which comprises a gas distribution block and a gas distribution gland; the gas distribution block passage is arranged in the gas distribution block, and the gas distribution gland passage is arranged in the gas distribution gland; the gas distribution gland is closely combined with the cooling port of the waste gas cooler.

10. The gas shielding mechanism according to claim 9, wherein The fourth gas protection assembly is further provided with a pressurizing mechanism; the pressurizing mechanism comprises a crank rod, a push rod, a spring base and a striker connected in sequence; the crank rod is connected with the gas distribution block; the spring base is fixedly connected with the limiting seat of the welding tool.

11. The gas shielding mechanism according to claim 10, wherein The second gas protection assembly is further provided with a positioning assembly arranged in the lower top plate of the welding tool; the positioning assembly comprises a reference link plate and a positioning pin.

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